xvEPA
United States
Environmental Protection
Agency
EPA/600/R-13/257 | September 2013 | www.epa.gov/ged
GULF OF MEXICO HYPOXIA RESEARCH
PROGRAM DATA REPORT
2002-2007
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This report was prepared by the U. S. Environmental Protection Agency, Office of Research and
Development, National Health and Environmental Effects Research Laboratory, Gulf Ecology
Division. This document has been reviewed in accordance with U.S. Environmental Protection
policy and approved for publication.
The project was administered from the Gulf Ecology Division (GED) of the USEPA Office of
Research and Development located in Gulf Breeze, FL. The project leader was Richard Greene;
other senior research scientists included: Richard Devereux, James Hagy, Janis Kurtz, John
Lehrter, and Michael Murrell. Key GED personnel for cruises and laboratory support included:
Alex Almario, Lee Anderson (MED) Jessica Aukamp, David Beddick, Jed Campbell, George
Craven, Marilynn Hoglund, Brandon Jarvis, Bob Quarles, Roman Stanley, Sherry Vickery, and
Diane Yates. A full list of the science staff during each cruise is included in Appendix B. For
shipboard support, special thanks go out to the ship's crews for their tremendous help and
hospitality.
This report should be cited as:
Murrell, M. C., J. R. Aukamp, D. L. Beddick Jr., R. Devereux, R. M. Greene, J. D. Hagy III, B.
M. Jarvis, J. C. Kurtz, J. C. Lehrter, and D. F. Yates. 2013. Gulf of Mexico hypoxia research
program data report: 2002-2007. U. S. Environmental Protection Agency, Washington, DC,
EPA/600/R-13/257.
11
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Table of Contents
1. INTRODUCTION
2. METHODS
...j
2-1. Survey Design 3
2-2. Data quality and validation 4
2-3. Water Column Sampling and Measurements 6
2-4. Sediment Sampling and Measurements 9
3. RESULTS 10
3-1. Station Maps by Cruise 12
3-2. Depth Distribution of Key Variables 19
3-3. Transect-Profile Plots of Key Variables 24
3-4. Water Column Integrated Bin Plots 33
3-5. Stacked Water Column Integrated Bin Plots 43
3-6. Vertically Binned Water Column Bin Plots 46
3-7. Vertically Binned Water Column Bin Plots - Ratios 75
3-8. Scatter Plots of CTD and in situ Variables 83
3-9. Surface Water Quality Along Cruise Tracks 86
3-10. Surface and Bottom Layer Currents 97
3-11. Water Column Process Stations 104
3-12. High Vertical Resolution Water Column Profiles 149
3-13. Sediment Characteristics 162
3-14. Water Column Physical Properties at Process Stations 183
3-15. Current Profiles, Shear, and Richardson Number (Ri) at Process Stations 214
3-16. Surface and Bottom YSI Time Series at Process Stations 224
APPENDIX A. PHYTOPLANKTON SPECIES LIST 238
APPENDIX B. CRUISE PARTICIPANTS 248
APPENDIX C. PUBLICATIONS RESULTING FROM THIS PROJECT 250
in
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Table of Figures
Figure 1-1 Hypoxia Time Series 1
Figure 2-1. Station Map 3
Figure 2-2. Water Quality Database Structure 5
Figure 2-3.Sediment Database Structure 6
Figure 3-1. Mississippi-Atchafalaya River Hydrograph 11
Figure 3-1-1. Survey Design, GM0212 13
Figure 3-1-2. Survey Design, GM0303 13
Figure 3-1-3. Survey Design, GM0306 14
Figure 3-1-4. Survey Design, GM0311 14
Figure 3-1-5. Survey Design, GM0404 15
Figure 3-1-6. Survey Design, GM0503 15
Figure 3-1-7. Survey Design, GM0509 16
Figure 3-1-8. Survey Design, GM0604 16
Figure 3-1-9. Survey Design, GM0606 17
Figure 3-1-10. Survey Design, GM0609 17
Figure 3-1-11. Survey Design, GM0704 18
Figure 3-1-12. Survey Design, GM0708 18
Figure 3-2-1. Depth Distribution of Temperature, Salinity, and Dissolved Oxygen 20
Figure 3-2-2. Depth Distribution of Particulate C, N, P, Chl-a, and Ratios 21
Figure 3-2-3. Depth Distribution of NH4, NO2, NO3, DIN, PO4, Si, and ratios 22
Figure 3-2-4. Depth Distribution of DOC, DON, DON, and ratios 23
Figure 3-3-1. Salinity Cross Shelf Profiles: Eastern Transects 25
Figure 3-3-2. Salinity Cross Shelf Profiles: Western Transects 26
Figure 3-3-3. DO Cross Shelf Profiles: Eastern Transects 27
Figure 3-3-4. DO Cross Shelf Profiles: Western Transects 28
Figure 3-3-5. Chi a Cross Shelf Profiles: Eastern Transects 29
Figure 3-3-6. Chi a Cross Shelf Profiles: Western Transects 30
Figure 3-3-7. TSS Cross Shelf Profiles: Eastern Transects 31
Figure 3-3-8. TSS Cross Shelf Profiles: Western Transects 32
Figure 3-4-1. Bottom Depth 34
Figure 3-4-2. Secchi Depth 35
Figure 3-4-3. Diffuse light attenuation coefficient 36
Figure 3-4-4. Maximum Brunt-Vaisala Frequency 37
Figure 3-4-5. Pycnocline Depth 38
Figure 3-4-6. Areal Primary Production 39
Figure 3-4-7. Volumetric Primary Production 40
Figure 3-4-8. Phytoplankton Abundance 41
Figure 3-4-9. Phytoplankton Biovolume 42
Figure 3-5-1. Surface Mixed Layer and Bottom Layer Depths 44
Figure 3-5-2. Euphotic Layer and Aphotic Layer Depths 45
Figure 3-6-1. Temperature 47
Figure 3-6-2. Salinity 48
Figure 3-6-3. Sigma T 49
Figure 3-6-4. Dissolved Oxygen (DO) 50
IV
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Figure 3-6-5. DO % saturation 51
Figure 3-6-6. Chlorophyll a (Chi) 52
Figure 3-6-7. Chlorophyll a-Estimated (Chle) 53
Figure 3-6-8. Total Suspended Solids (TSS) 54
Figure 3-6-9. Total Suspended Solids - Estimated (TSSe) 55
Figure 3-6-10. Paniculate Carbon (PC) 56
Figure 3-6-11. Particulate Nitrogen (PN) 57
Figure 3-6-12. Particulate Phosphorus (PP) 58
Figure 3-6-13. Ammonium (NH4) 59
Figure 3-6-14. Nitrite (NO2) 60
Figure 3-6-15. Nitrite + Nitrate (NOx) 61
Figure 3-6-16. Total Dissolved Nitrogen (TDN) 62
Figure 3-6-17. Dissolved Organic Nitrogen (DONs) 63
Figure 3-6-18. Total Nitrogen (TN) 64
Figure 3-6-19. Phosphate (DIP) 65
Figure 3-6-20. Total Dissolved Phosphorus (TDP) 66
Figure 3-6-21. Dissolved Organic Phosphorus (DOP) 67
Figure 3-6-22. Total Phosphorus (TP) 68
Figure 3-6-23. Silicate (Si) 69
Figure 3-6-24. Dissolved Organic Carbon (DOC) 70
Figure 3-6-25. Dissolved Inorganic Carbon (DIG) 71
Figure 3-6-26. Plankton Community Respiration 72
Figure 3-6-27. Bacterioplankton Production 73
Figure 3-6-28. Bacterioplankton Abundance 74
Figure 3-7-l.DIN:DIP Ratio 76
Figure 3-7-2. TDNs:P Ratio 77
Figure 3-7-3. Silica:N Ratio 78
Figure 3-7-4. DOC:DONs Ratio 79
Figure 3-7-5. PC:PN Ratio 80
Figure 3-7-6. PC:PP Ratio 81
Figure 3-7-7. PN: PP Ratio 82
Figure 3-8-1. Fluorescence vs. Extracted Chlorophyll a 84
Figure 3-8-2. OBS or Beam Attenuation vs Total Suspended Solids 85
Figure 3-9-1. Surface Water Quality along Cruise Track, GM0303 87
Figure 3-9-2. Surface Water Quality along Cruise Track, GM0306 88
Figure 3-9-3. Surface Water Quality along Cruise Track, GM0311 89
Figure 3-9-4. Surface Water Quality along Cruise Track, GM0503 90
Figure 3-9-5. Surface Water Quality along Cruise Track, GM0509 91
Figure 3-9-6. Surface Water Quality along Cruise Track, GM0604 92
Figure 3-9-7. Surface Water Quality along Cruise Track, GM0606 93
Figure 3-9-8. Surface Water Quality along Cruise Track, GM0609 94
Figure 3-9-9. Surface Water Quality along Cruise Track, GM0704 95
Figure 3-9-10. Surface Water Quality along Cruise Track, GM0708 96
Figure 3-10-1. Surface and Bottom Layer Currents, GM0503 98
Figure 3-10-2. Surface and Bottom Layer Currents, GM0509 99
Figure 3-10-3. Surface and Bottom Layer Currents, GM0606 100
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Figure 3-10-4. Surface and Bottom Layer Currents, GM0609 101
Figure 3-10-5. Surface and Bottom Layer Currents, GM0704 102
Figure 3-10-6. Surface and Bottom Layer Currents, GM0708 103
Figure 3-11-1. Temperature 105
Figure 3-11-2. Salinity 106
Figure 3-11-3. Sigma T 107
Figure 3-11-4. Dissolved oxygen (mg L"1) 108
Figure 3-11-5. Dissolved oxygen (mmol m"3) 109
Figure 3-11-6. Dissolved oxygen (% saturation) 110
Figure 3-11-7. Chlorophyll fluorescence Ill
Figure 3-11-8. Optical backscatter 112
Figure 3-11-9. Chlorophyll a (Chi a) 113
Figure 3-11-10. Particulate carbon (PC) 114
Figure 3-11-11. Paniculate nitrogen (PN) 115
Figure 3-11-12. Particulate phosphorus (PP) 116
Figure 3-11-13. Total suspended solids (TSS) 117
Figure 3-11-14. PC:PN Ratio 118
Figure 3-11-15. PC:PP Ratio 119
Figure 3-11-16. PN:PP Ratio 120
Figure 3-11-17. PC: ChlaRatio 121
Figure 3-11-18. Ammonium (NH4+) 122
Figure 3-11-19. Nitrite (NO2-) 123
Figure 3-11-20. Dissolved nitrite plus nitrate (NOx) 124
Figure 3-11-21. Dissolved inorganic nitrogen (DIN) 125
Figure 3-11-22. Dissolved inorganic phosphate (DIP) 126
Figure 3-11-23. Dissolved silica (Si) 127
Figure 3-11-24. DIN:DIP Ratio 128
Figure 3-11-25. DIN:Si Ratio 129
Figure 3-11-26. Dissolved inorganic carbon (DIG) 130
Figure 3-11-27. Dissolved organic carbon (DOC) 131
Figure 3-11-28. Total dissolved nitrogen (TDNs) via Shimadzu 132
Figure 3-11-29. DON via Shimadzu 133
Figure 3-11-30. Organic fraction of total dissolved nitrogen (DONs/TDNs) 134
Figure 3-11-31. DOC:DONs Ratio 135
Figure 3-11-32. Total dissolved nitrogen via wet chemistry (TDNw) 136
Figure 3-11-33. Total dissolved phosphorus via wet chemistry (TDPw) 137
Figure 3-11-34. DON via wet chemistry 138
Figure 3-11-35. Dissolved organic phosphorus via wet chemistry (TDPw-DIP) 139
Figure 3-11-36. Organic fraction of total dissolved nitrogen via wet chemistry 140
Figure 3-11-37. Organic fraction of total dissolved phosphorus (DOPw/TDPw) 141
Figure 3-11-38. TDNw:TDPw Ratio 142
Figure 3-11-39. DOC:DONw Ratio 143
Figure 3-11-40. Plankton community respiration (WR) 144
Figure 3-11-41. Bacterioplankton production (BP) 145
Figure 3-11-42. Bacterioplankton abundance (BA) 146
Figure 3-11-43. Cell-specific bacterioplankton production (BP/BA)) 147
VI
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Figure 3-11-44. BP:WR Ratio 148
Figure 3-12-1. High Vertical Resolution Profiles: GM0606, Z01 150
Figure 3-12-2. High Vertical Resolution Profiles: GM0606, Z02 151
Figure 3-12-3. High Vertical Resolution Profiles: GM0606, Z03 152
Figure 3-12-4. High Vertical Resolution Profiles: GM0609, Z01 153
Figure 3-12-5. High Vertical Resolution Profiles: GM0609, Z02 154
Figure 3-12-6. High Vertical Resolution Profiles: GM0609, Z03 155
Figure 3-12-7. High Vertical Resolution Profiles: GM0704, Z02 156
Figure 3-12-8. High Vertical Resolution Profiles: GM0704, Z03 157
Figure 3-12-9. High Vertical Resolution Profiles: GM0704, Z04 158
Figure 3-12-10. High Vertical Resolution Profiles: GM0708, Z02 159
Figure 3-12-11. High Vertical Resolution Profiles: GM0708, Z03 160
Figure 3-12-12. High Vertical Resolution Profiles: GM0708, Z04 161
Figure 3-13-1. Granulometry 163
Figure 3-13-2. Wet Bulk Density 164
Figure 3-13-3. Porosity and % Water 165
Figure 3-13-4. PorewaterDIC 166
Figure 3-13-5. Porewater pH 167
Figure 3-13-6. Porewater Nitrate and Nitrite 168
Figure 3-13-7. Porewater ammonium (NH4+) 169
Figure 3-13-8. Porewater silicate 170
Figure 3-13-9. Porewater Phosphate 171
Figure 3-13-10. Porewater Sulfate 172
Figure 3-13-11. Porewater DOC 173
Figure 3-13-12. Porewater TON 174
Figure 3-13-13. Solid Phase Organic and Total Nitrogen 175
Figure 3-13-14. SolidPhase Organic and Total Carbon 176
Figure 3-13-15. Solid Phase Inorganic and Total Phosphorus 177
Figure 3-13-16. Porewater Reduced and Total Iron 178
Figure 3-13-17. Solid Phase Reduced and Total Iron 179
Figure 3-13-18. Sediment Chlorophyll a 180
Figure 3-13-19. Sulfate Reduction Rate 181
Figure 3-13-20. Total Reduced Sulfide 182
Figure 3-14-1. Temperature, Salinity, and Sigma T: GM0604, Z01 184
Figure 3-14-2. DO, DO % saturation, Chi, and OBS: GM0604, Z01 185
Figure 3-14-3. Temperature, Salinity, and Sigma T: GM0604, Z02 186
Figure 3-14-4. DO, DO % saturation, Chi, and OBS: GM0604, Z02 187
Figure 3-14-5. Temperature, Salinity, and Sigma T: GM0604, Z03 188
Figure 3-14-6. DO, DO % saturation, Chi, and OBS: GM0604, Z03 189
Figure 3-14-7. Temperature, Salinity, and Sigma T: GM0606, Z01 190
Figure 3-14-8. DO, DO % saturation, Chi, and OBS: GM0606, Z01 191
Figure 3-14-9. Temperature, Salinity, and Sigma T: GM0606, Z02 192
Figure 3-14-10. DO, DO % saturation, Chi, and OBS: GM0606, Z02 193
Figure 3-14-11. Temperature, Salinity, and Sigma T: GM0606, Z03 194
Figure 3-14-12. DO, DO % saturation, Chi, and OBS: GM0606, Z03 195
Figure 3-14-13. Temperature, Salinity, and Sigma T: GM0609, Z01 196
vn
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Figure 3-14-14. DO, DO % saturation, Chi, and OBS: GM0609, Z01 197
Figure 3-14-15. Temperature, Salinity, and Sigma T: GM0609, Z02 198
Figure 3-14-16. DO, DO saturation, Chi, and OBS: GM0609, Z02 199
Figure 3-14-17. Temperature, Salinity, and Sigma T: GM0609, Z03 200
Figure 3-14-18. DO, DO saturation, Chi, and OBS: GM0609, Z03 201
Figure 3-14-19. Temperature, Salinity, and Sigma T: GM0704, Z02 202
Figure 3-14-20. DO, DO % saturation, Chi, and OBS: GM0704, Z02 203
Figure 3-14-21. Temperature, Salinity, and Sigma T: GM0704, Z03 204
Figure 3-14-22. DO, DO % saturation, Chi, and OBS: GM0704, Z03 205
Figure 3-14-23. Temperature, Salinity, and Sigma T: GM0704, Z04 206
Figure 3-14-24. DO, DO % saturation, Chi, and OBS: GM0704, Z04 207
Figure 3-14-25. Temperature, Salinity, and Sigma T: GM0708, Z02 208
Figure 3-14-26. DO, DO % saturation, Chi, and OBS: GM0708, Z02 209
Figure 3-14-27. Temperature, Salinity, and Sigma T: GM0708, Z03 210
Figure 3-14-28. DO, DO % saturation, Chi, and OBS: GM0708, Z03 211
Figure 3-14-29. Temperature, Salinity, and Sigma T: GM0708, Z04 212
Figure 3-14-30. DO, DO % saturation, Chi, and OBS: GM0708, Z04 213
Figure 3-15-1. Currents, Shear, and Ri: GM0609, Z01 215
Figure 3-15-2. Currents, Shear, andRi: GM0609, Z02 216
Figure 3-15-3. Currents, Shear, andRi: GM0609, Z03 217
Figure 3-15-4. Currents, Shear, andRi: GM0704, Z02 218
Figure 3-15-5. Currents, Shear, andRi: GM0704, Z03 219
Figure 3-15-6. Currents, Shear, andRi: GM0704, Z04 220
Figure 3-15-7. Currents, Shear, andRi: GM0708, Z02 221
Figure 3-15-8. Currents, Shear, andRi: GM0708, Z03 222
Figure 3-15-9. Currents, Shear, andRi: GM0708, Z04 223
Figure 3-16-1. YSI Time Series: GM0604, Z02 225
Figure 3-16-2. YSI Time Series, GM0606, Z01 226
Figure 3-16-3. YSI Time Series: GM0606, Z02 227
Figure 3-16-4. YSI Time Series: GM0606, Z03 228
Figure 3-16-5. YSI Time Series: GM0609, Z01 229
Figure 3-16-6. YSI Time Series: GM0609, Z02 230
Figure 3-16-7. YSI Time Series: GM0609, Z03 231
Figure 3-16-8. YSI Time Series: GM0704, Z02 232
Figure 3-16-9. YSI Time Series: GM0704, Z03 233
Figure 3-16-10. YSI Time Series: GM0704, Z04 234
Figure 3-16-11. YSI Time Series: GM0708, Z02 235
Figure 3-16-12. YSI Time Series: GM0708, Z03 236
Figure 3-16-13. YSI Time Series: GM0708, Z04 237
Vlll
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Table of Tables
Table 2-1. Survey Cruises 2002-2007 4
Table 2-2. Process Leg Cruises 2006-2007 4
IX
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1. INTRODUCTION
The Mississippi-Atchafalaya River Basin drains approximately 40% of the United States' land
area, delivering fresh water, sediments and nutrients to the Gulf of Mexico. Over the past several
decades agricultural nitrogen fertilizer use in the United States has increased, and resulted in
increased nutrient loading to the Gulf of Mexico. Every summer, hypoxia (operationally defined
as dissolved oxygen < 2 mg I"1) develops on large portions of the Louisiana-Texas continental
shelf west of the Mississippi River delta. The demonstrated linkages between hypoxia and
increased anthropogenic nutrient loading is a national environmental policy concern. Systematic
shelf-wide mapping of mid-summer hypoxia was begun in 1985, and over the subsequent 27
years, showed that the area of hypoxic bottom waters varies from year-to-year with a long-term
average (1985-2013) is 13,600 km2.
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1990
1995
2000
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Figure 1-1 Hypoxia Time Series. Time series of the areal extent of hypoxia on the Louisiana
continental shelf, based on spatial interpolations from annual surveys conducted by the Louisiana
Universities Marine Consortium (LUMCON) in late July (http:\\gulfhypoxia.net). Superimposed
are the 5 year running average and the long-term average.
In response to increasing awareness of hypoxia in the Gulf of Mexico, the Mississippi River/Gulf
of Mexico Watershed Nutrient Task Force was established in 1997
(http://www.epa.gov/msbasin/taskforce/index.htm). The Task Force, made up of senior
representatives of federal, state and tribal agencies, was charged with assessing and coordinating
actions to manage nutrients in the drainage basin to reduce of the hypoxic zone. On November
13, 1998, Congress enacted the Harmful Algal Bloom and Hypoxia Control Act (HABFIRCA;
Title VI of P.L. 105-383, section 604(b)), which called for: "1) the establishment of an inter-
agency task force on harmful algal blooms and hypoxia, 2) a national assessment on harmful
algal blooms, 3) a national assessment on hypoxia, and 4) an assessment and an action plan for
addressing hypoxia in the Gulf of Mexico". HABFIRCA was re-authorized in 2004 with the
Harmful Algal Bloom and Hypoxia Amendments Act (P.L. 108-456). In 2000, the task force
published the Integrated Assessment of Hypoxia in the Northern Gulf of Mexico (CENR, 2000),
followed in 2001 by the Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the
1
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Northern Gulf of Mexico, and referred to as the "Hypoxia Action Plan". This Action Plan was
updated in 2008. Among other things, the Hypoxia Action Plan recognized the need for
cooperation between states, tribes, and relevant federal agencies, and called for a comprehensive
monitoring, modeling and research strategy. Explicit in the Hypoxia Action Plan was the need
for expanded monitoring, enhanced research and modeling efforts, and increased stakeholder
education and national awareness programs.
EPA's Office of Research and Development initiated the Gulf Hypoxia Research and Modeling
Program in 2002 to develop a coordinated risk-based forecasting modeling framework to aid
water resource managers in making scientifically defensible nutrient management decisions to
reduce the areal extent of hypoxia, and restore natural habitats, and restore food web
assemblages along the Louisiana Texas continental shelf. The field monitoring and ecological
process research required for the development of a consensus modeling framework was GED's
component of this task, which included 1) characterizing the spatial and temporal variability in
oceanographic state and process variables in the Gulf of Mexico hypoxic zone, 2) improving
resolution of the seaward and down-plume boundary conditions of the model domain, 3)
quantifying key processes influencing hypoxia to improve predictive models, and 4) developing
a relational database to support model development.
The data described in this report was collected during 12 oceanographic cruises conducted from
2002-2007. The project was supported by the US EPA Office of Research and Development, in
partnership with the US EPA Gulf of Mexico Program Office, the Office of Water, and Regions
4 and 6. The sampling domain largely covered the area of the shelf affected by summer hypoxia
as defined by LUMCON July surveys. The research cruise component of this project was a major
effort of Gulf Ecology Division (GED) staff; starting in December 2002 and extending until
August 2007, during which time a total of 12 surveys were conducted (Tables 2-1 and 2-2,
Appendix B). Completing the laboratory analysis of collected samples from these cruises
extended well into 2008. From 2002-2005, the cruises were comprised of conductivity,
temperature, depth (CTD) and water column sampling surveys with benthic stations at a subset
of these stations. In 2006-2007, cruise activities were split into survey and process legs. During
the survey leg, no benthic samples were collected. During the process leg, intensive water
column and benthic sampling was conducted at select stations over a 30-36 h period.
The primary goal of the research was to collect an extensive empirical dataset to describe the
distribution and dynamics of nutrients and organic matter in the region. The dataset is unique
from other large projects conducted in the Gulf of Mexico (NECOP, LaSER, SEAMAP,
NGOMEX, MCH, LATEX) in the number and nature of the process measurements. Process rate
measurements are a necessary component for constraining models that quantify the connection
between nutrient loads and the ecosystem responses. Currently several groups of scientists have
developed 3D hydrodynamic models coupled to water quality (biogeochemical) models. Of wide
interest is the application of these models to accurately predict the timing and location of
hypoxic water mass formation.
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2. METHODS
2-1. Survey Design
The study area for these cruises encompassed the shallow continental shelf region (5 - 100 m
total water depth) from the Mississippi River west to near the Texas border. Three different
research vessels were used for the project: 1) EPA Ocean Survey Vessel (OSV) Peter W.
Anderson, 2), the University of Texas' RV Longhorn , and 3) the EPA OSV Bold.
Figure 2.1 is a map of the Louisiana continental shelf showing stations oriented along inshore-
offshore transects adapted from the Louisiana Universities Marine Consortium (LUMCON)
sampling design. The red polygon depicts the region where hypoxia has been historically
observed by LUMCON during annual July surveys. The 10, 30, 50, and 100 m isobaths are
shown in the figure.
30°W
29°N-
28'N-
94°W
93°W
92°W
91°W
90°W 89°W
Figure 2-1. Sampling Stations on the Louisiana Continental Shelf
The stations were arranged along inshore-to-offshore (essentially north-to-south) transects,
denoted by X, M, A, B, etc, spaced at 20 n. mi. intervals with 8 to 12 stations per transect. The
station grid and transect designations were nearly identical to those used by LUMCON for thieir
annual mid-summer hypoxia surveys since 1985. Our grid included stations further offshore than
LUMCON. We also added an additional "M" transect into the Mississippi River channel.
Table 2-1 lists survey cruises conducted from 2002 - 2007. The Cruise ID is of the form
GMMMYY, where GM is the Gulf of Mexico, YY is the 2 digit year, and MM is the month.
Included are the number of CTD stations occupied, the number of water column samples
collected, the number of stations where additional benthic samples were collected and the letter
codes denoting the transects occupied. Benthic samples in 2006-2007 cruises were obtained on
the process leg.
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Table 2-1. Survey Cruises 2002-2007
Cruise ID
GM0212
GM0303
GM0306
GM0311
GM0404
GM0503
GM0509
GM0604
GM0606
GM0609
GM0704
GM0708
Dates
3-12 Dec. 2002
18-27 Mar. 2003
10-20 Jun. 2003
6-16 Nov. 2003
2-6 Apr. 2004
22 -31 Mar. 2005
27 Sep. -7 Oct. 2005
13-17 Apr. 2006
6-12 Jun. 2006
6-12 Sep. 2006
1-7 May 2007
27-31 Aug. 2007
#CTD
Stations
37
65
51
70
22
66
65
65
85
92
89
87
# Water
Samples
88
182
117
140
75
151
139
111
194
199
208
170
# Benthic
Stations
0
6
6
10
8
7
0
o
J
o
J
o
J
4
o
J
Ship
Anderson
Anderson
Anderson
Anderson
Longhorn
Longhorn
Bold
Bold
Bold
Bold
Bold
Bold
Transects occupied
A, D, H, J
A, C, D, F, H, I, G, J
M, A, C, D, E, F, H
M, A, B, C, D, E, F, G, H, J
M, A, B, C, D, E, F*
M, A, B, C, D, F, J, H
X, M, A, B, C, D, F, M
X, M, A, B, C, D, E, F, G, H, J
X, M, A, B, C, D, E, F, G, H, J, K
X, M, A, B, C, D, E, F, G, H, J, K
X, M, A, B, C, D, E, F, G, H, J, K
X, M, A, B, C, D, E, F, G, H, J, K
TOTALS
794
1774
53
During 2006-2007, the cruises included a "process leg". The process leg entailed intensive
sampling of relatively few fixed stations (3 or 4 per cruise) for 30-36 h. Sampling involved CTD
casts and water column sampling at 3-6 hour intervals, a series of high vertical resolution
samples, and intensive benthic sampling. Table 2-2 lists process cruises in 2006-2007. The
station names depicted the different zones occupied, with Z01 being near the Mississippi River
plume (near survey station A04), Z02 and Z04 were midway between the Mississippi and
Atchafalaya outflows (near survey stations C06 and C02, respectively) and Z03 was on the
western shelf offshore of the Atchafalaya River outflow (near survey station H04). Included are
the number of CTD profiles and water samples and the number of high vertical resolution (HR)
profiles and water samples. Benthic sampling accompanied all stations. Appendix B lists the
scientific personnel who participated in each cruise.
Table 2-2. Process Leg Cruises 2006-2007
Cruise ID
GM0604
GM0606
GM0609
GM0704
GM0708
TOTALS
Dates
5 - 12 Apr 2006
13- 18 Jun 2006
13 - 18 Sep 2006
25 -30 Apr 2007
19-26Aug2007
Stations
occupied
Z01,Z02, Z03
Z01,Z02, Z03
Z01,Z02, Z03
Z02, Z03, Z04
Z02, Z03, Z04
#CTD
Profiles
23
31
34
41
36
165
# CTD Water
Samples
75
124
136
82
72
489
#HR
Profiles
6
6
6
7
9
34
#HR Water
Samples
95
94
94
96
98
477
2-2. Data quality and validation
The data generated from the field surveys have been evaluated at multiple steps along the path
from sample collection, to analysis, to final incorporation into the database (Quality Assurance
Project Plan, Greene 2007). During sample collection onboard ship, critical information was
recorded on standardized data forms or in laboratory notebooks. The data were entered into
spreadsheets, and data quality issues (e.g. missing information, illegible information, etc) were
addressed and resolved, often while still onboard ship. Upon return to the laboratory, the samples
-------
were reconciled with the field data logs, at which time data quality issues (e.g. missing or
mislabeled samples) were resolved. Each analysis used standard operational procedures (SOP),
maintained with the study file. Each SOP included quality assurance and quality control
(QA/QC) guidelines to establish analyte-specific criteria for data accuracy, precision, and
method detection limits. For routine analyses, standardized reports were generated that included
a narrative description of the analysis, data quality issues, and hardcopy and electronic copies of
the data. Data reports were reviewed by a second qualified analyst and the data manager for
accuracy, and revised as needed. At this stage, the data were incorporated into the database. The
database software established and enforced referential integrity, which provided a further check
that the data were correctly associated with key variables (e.g., Cruise, Station, Depth), thus
preventing 'orphan' observations. Upon incorporation into the database, the data were examined
graphically, to evaluate general data quality and to identify potential outliers. Detailed
descriptions of QA procedures are included in the Quality Assurance Project Plans for this
project (Greene 2003, 2005, 200?;.
Figures 2-2 and 2-3 depict graphical views of the relational database structure in Microsoft
Access for the water quality and sediment databases, respectively. The key variables (e.g.,
Cruise, Stn) provide common links to all the data tables in the database. For example, in the
water quality database, the tables named "Niskins" and "Events" are singularly important
because they serve to associate every measurement with the what/when/where details of sample
collection (latitude, longitude, depth below surface, and date-time). In the sediment database, the
"Events sediment" and "root table" tables serve the comparable function. All the data in the
database are directly or indirectly linked to these key tables. For simplicity, these figures show
only a subset of the full set of data tables in each database. Not depicted are quality assurance
and report tracking tables, and various other ancillary tables.
Figure 2-2. Water Quality Database Structure
-------
Lruise
tation
Sediment depth
—Isample *
NH4
Reportdate/batch
QA
Figure 2-3. Sediment Database Structure
2-3. Water Column Sampling and Measurements
This section briefly summarizes the water column measurements made during the course of this
project. Detailed descriptions are included in the numerous Standard Operating Procedures
(SOP's), referenced in the project QAPP (Greene 2003, 2005, 2007).
Seabird CTD 911 Conductivity-Temperature-Depth (CTD)
The CTD instrument package forms the foundation of the water column sampling program,
providing high resolution data on the physical and chemical characteristics of the water column
at each station. The Seabird 911 system included sensors for conductivity (SEE 4), temperature
(SEE 3), pressure, dissolved oxygen (SEE 43) and chlorophyll fluorescence (Wetlabs Wetstar),
beam attenuation (Wetlabs C-Star) and optical backscatter (Seapoint). During daylight periods,
profiles photosynthetically active radiation (PAR) was also measured (Biospherical QSP-240).
The CTD data were post-processed using a multi-step procedure, resulting bin averaged data
files (usually 1 m intervals). Derived variables calculated from the raw data during processing
include: salinity, seawater density (Sigma T), depth, and diffuse downwelling light attenuation
coefficient. The CTD package included a rosette of sample bottles (General Oceanics, Inc) to
collect water samples from discrete layers of the water column.
-------
Seabird SBE 25 Conductivity-Temperature-Depth (CTD) system
During 2006-2007 process leg cruises, additional water column measurements were made at high
vertical-resolution using a SBE25 CTD system integrated with a submersible pump. This setup
allowed water samples to be collected in thin layers closely matched with the CTD sensor array.
The SBE25 included temperature (SBE 3), conductivity (SBE 4), pressure, dissolved oxygen
(DO) (SBE 43), and chlorophyll fluorescence (Wetlab).
YSI Handheld Meters
During 2006-2007, a handheld YSI63 and/or YSI 5000 instrument was used as a secondary
check on CTD data. Temperature, salinity, and pH were measured in transfer bottles collected
from the Niskin array. Note that these temperature readings were not considered accurate
reflection of in situ conditions, but served as relative quality check that bottles were correctly
labeled (cool deep waters). Additionally, we used the handheld units during the process leg
cruises to measure the characteristics of water collected from the submersible pump during high
resolution profiling as a check on the CTD data.
Secchi disk depth
During daylight hours, a 0.25 m diameter Secchi disk was lowered into the water column on a
line with 1/2 meter markings to the point where it was no longer visible. This depth, estimated to
the nearest 0.1 m, was recorded.
Dissolved Nutrients and Organic Carbon
Each water sample was filtered through a combusted (450°C, 1 h) 47 mm Whatman GF/F filter
(nominal pore size 0.7 jim), and the filtrate was stored at -70°C until analysis. In the laboratory,
inorganic nutrients (NH4, NO2, NO3, PO4, SiO2) were analyzed via standard automated
colorometric methods (APHA 2005). Total nitrogen and phosphorus were analyzed by persulfate
digestion followed by automated colorimetric analysis of nitrate and orthophosphate. Samples
for dissolved organic carbon and total dissolved nitrogen were analyzed by automated high
temperature catalytic oxidation.
Chlorophyll-a (Chl-a)
Samples for Chl-a were filtered onto 25 mm Whatman GF/F filters and stored in the dark at -
70°C until analysis. In the laboratory, chlorophyll-a was extracted from the filters in methanol
with sonication and the extract was quantified fluorometrically (Welshmeyer 1994).
Particulate Carbon (PC). Nitrogen (PNX and Phosphorus (PP)
Samples for these constituents were collected onto combusted 25 mm Whatman GF/F filters and
stored at -70°C (PC, PN) or in the dark at room temperature (PP) until analysis. In the laboratory,
PC and PN were analyzed via combustion in an automated elemental analyzer. For PP samples
were digested (persulfate) and analyzed for orthophosphate via standard colorometric methods.
-------
Total Suspended Solids (TSS)
Samples for TSS were collected onto pre-weighed 47 mm glass fiber filters (GF/F or equivalent),
rinsed thoroughly with deionized water to remove salts, and stored at -20°C until analysis. In the
laboratory, filters were dried and reweighed.
Dissolved Oxygen (DO)
Water samples were collected into glass BOD bottles and fixed immediately with Winkler
reagents. For GM0212 and GM0303, titrations were conducted in the lab following the cruise.
Otherwise, titrations were conducted on board ship using micro-buret and auto-titration methods.
The DO measurements were used as a check against polarographic DO data from CTD and
bench-top meters.
Phytoplankton Abundance and Biovolume
Water samples (250-500 ml) were preserved in 1% glutaraldehyde, 1% formaldehyde, or -0.5%
acid Lugols (depending on cruise), and stored either at 4°C (aldehydes) or in the dark at room
temperature (Lugols) until analysis. Phytoplankton were identified to lowest identifiable taxon
via the Utermohl method using an inverted microscope (Utermohl 1958). Tax on-specific length
and width measurements on a subset of representative organisms, and biovolume was calculated
by applying appropriate geometric formulae. Abundances were tallied for each taxon, and
combined with taxon-specific biovolume to calculate total phytoplankton biolvolume.
Dissolved Inorganic Carbon (DIG)
Water samples for DIG were run onboard ship using a Shimadzu TOG 5050 analyzer, which was
routinely calibrated against seawater standards.
Primary Production
Water samples were amended with NaH14CO3 tracer and were incubated in natural sunlight in a
running seawater bath to maintain surface temperatures. Replicate samples were shaded to 3%,
6%, 13%, 25%, 50%, 100% (no screening) of full sunlight, using neutral density screening. After
24 hours, the samples were filtered onto 25 mm Millipore HA filters and the radiotracer
incorporated into phytoplankton was quantified by liquid scintillation counting. Results were
reported in Lehrter et al. 2009 (See Appendix C).
Bacterioplankton abundance (2003-2005)
Water samples (20 ml) were fixed with 2% formaldehyde and stored at 4°C until counting via
standard epifluorescence microscopy, using DAPI stain.
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Bacterioplankton Production
Water samples were amended with the amino acid radiotracer 3H-L-leucine, and incubated in the
dark for 1 to 2 hours. After incubation, the incorporated label was extracted and quantified by
liquid scintillation counting.
Plankton Community Respiration
Water samples were collected into gas-tight BOD bottles. Dissolved oxygen concentrations were
measured immediately and again after 24 h using a polarographic probe. Results reported in
Murrell and Lehrter 2011 and Murrell et al. 2013 (See Appendix C).
Surface Mapper
The surface mapper system measured the water quality of surface water supplied from ship's hull
pump and logged with the ship's position at regular intervals along the cruise track. The
approximate water depth sampled was 1-2 m while underway and ~4 m otherwise. The
instrument package included a multi-probe instrument (YSI 6600 EDS) interfaced with global
positioning system (GPS) receiver. Sensors included temperature, salinity, chlorophyll
fluorescence, optical backscatter, and pH.
Acoustic Doppler Current Profiler (ADCP)
Point measurements of current velocity profiles were made at each station (not in underway
mode) using a bottom-tracking 600 kHz Acoustic Doppler Current Profiler (ADCP (RDI
Instruments, Inc.). The ADCP was deployed 1 m below the surface looking downward, and
interfaced with the ship's gyrocompass to orient the instrument. Data were recorded into bin
depths from 0.5 to 2 m depending on the water depth at the station. Profiles were collected at
depths up to 60 m and the current profile was resolved by compiling data from a 1 to 3 minute
deployment period. Additionally, continuous deployment of the ADCP occurred during extended
occupation (30-36 hr) at process stations during 2006-2007.
2-4. Sediment Sampling and Measurements
Bulk and Porewater Characteristics
Sediments were sampled for chlorophyll-a, percent organic matter (as % loss on ignition), total
carbon, total nitrogen, total phosphorus, grain size distribution (% sand, % silt, % clay), wet bulk
density, and porosity. During 2003-2005, only the surficial sediment layers were sampled (top 2
cm). During 2006-2007, samples were collected at multiple depth intervals down to -18 cm. In
addition to the above constituents, samples were analyzed for a variety of pore-water (SO4, Mn,
Fe) and solid phase (AVS, Total S, Fe) constituents.
-------
Oxygen, Nutrient and Carbon Fluxes
Benthic fluxes were measured using sediment cores (10 cm diameter x 40 cm length) collected
using a box-corer (2003-2005) or a multi-corer (2006-2007). Cores were incubated on board ship
in darkness at near in situ temperatures. Changes in DO concentrations in the overlying water
were measured at several time points over the 6-12 hour incubation using a polarographic sensor
(2003-2005). During 2006-2007, additional water samples were collected for a variety of
analytes, including N2/Ar/O2 via membrane inlet mass spectrometry, and DIG, NO2, NO3,
PO4, SiO2, and NH4 via methods described above.The results of these incubations were
published in 2 peer-reviewed articles: Murrell and Lehrter (2011) and Lehrter et al. (2012).
Sulfate Reduction Rates
Sulfate reduction rates were measured by amending the sediments cores with radiotracer
Na35SO4 and incubating for several hours. The reduced label (35S~) was extracted using a 2 step
distillation procedure to recover the acid volatile sulfide (AVS) and chromium reduced sulfide
(CRS) fractions. The extracted radiolabel was quantified by liquid scintillation counting.
3. RESULTS
The data collected from the cruises are presented in graphical forms that summarize various
results and show numerous aspects of the patterns in hydrographic and chemical variables
observed during the cruises. The figures have a variety of formats, and each group is introduced
briefly in the sections below. In this introductory section to the presentation of the results, Figure
3-1 is included to show the Mississippi-Atchafalaya River discharge during the study period.
Data represent combined flow from the U.S. Army Corps of Engineers gauging stations:
Mississippi River at Tarberts Landing and Atchafalaya River at Simmsport. Arrows denote
timing of cruises. The solid line depicts monthly average combined flow. For comparison, the
shaded area depicts the long-term average flow (1950-2007, shaded area). Vertical lines depict
calendar year breaks.
10
-------
-term average
2002-2007
I
0
Jul Jan Jul Jan Jul Jan Jul Jan Jul Jan Jul
2002 I 2003 I 2004 I 2005 | 2006 I 2007
Figure 3-1. Hydrograph Depicting Combined Flows of the Mississippi and Atchafalaya
Rivers.
11
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3-1 .Station Maps by Cruise
The following set of 12 of maps show the stations sampled during each cruise. While most
cruises adopted a common design, these maps indicate the specific stations occupied during each
cruise. The black symbols indicate stations where CTD and water samples were collected. The
red symbols indicate stations where benthic samples were collected.
12
-------
30°N-
29° N
Okm 50km 100km
AO
28° N
94°W
93°W 92°W 91°W 90°W
Figure 3-1-1. Survey Design, GM0212.
89 °W
30°N~-
29°N-
Okm 50km 100km
28°N--
94°W
93°W
92°W
91°W
90°W
Figure 3-1-2. Survey Design, GM0303.
89°W
13
-------
30°N-
Okm 50km 100km
B
^r t—-i j$F
N^lifii
29°/V
90°w
89°M/
Figure 3-1-3. Survey Design, GM0306.
30°N-~
0 km 50 km 100 km
93°W
92°W
91°W
90°W
89°W
Figure 3-1-4. Survey Design, GM0311.
14
-------
30 °N- -
92°W
91°W
90°W
Figure 3-1-5. Survey Design, GM0404.
89°W
30° N—
Okm 50km 100km
93°W 92°W 91°W 90°W
Figure 3-1-6. Survey Design, GM0503.
89°W
15
-------
30°A/--
29 "A/--
28°N
94 "W
Okm 50km 100km
9-Tl/V
90°M/
89°H/
Figure 3-1-7. Survey Design, GM0509.
30 "N-
29° N
0 km 50 km 100 km
28° N-
94°W
93°W
92°W
91°W
90°W
89°W
Figure 3-1-8. Survey Design, GM0604.
16
-------
30°N
0 km 50 km 100 km
93°W
92°W
91°W
90°W
89°W
Figure 3-1-9. Survey Design, GM0606.
tN
30°N-
0 km 50 km 100 km
—t—
' AO
29 "N-
28°N
94°W
93°W
92°W
91°W
90°W
89°W
Figure 3-1-10. Survey Design, GM0609.
17
-------
30°N-
0 km 50 km 100 km
93°W 92°W 91°W 90°W
Figure 3-1-11. Survey Design, GM0704.
89°W
30°N-
93°W 92°W 91°W 90°W
Figure 3-1-12. Survey Design, GM0708.
89°W
18
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3-2. Depth Distribution of Key Variables
The following 4 figures show data collected across the shelf from 2002-2007. The data include
the subset of CTD data that match discrete water sample collections. The first figure shows the
distribution of temperature (°C), salinity, and dissolved oxygen (DO, mmol O2 m"3. Comparable
distributions were included from NOAA's World Ocean Database (http://www.nodc.noaa.gov)
for the western Gulf of Mexico (NODC 1994). The dotted vertical line on the DO plot depicts
hypoxia (<63 mmol O2 m"3 or <2 mg O2 L"1). The second figure shows the depth distributions of
key particulate constituents: carbon (PC, jimol C L"1), nitrogen (PN, jimol N L"1), phosphorus
(PP, |imol P I/1), and chlorophyll a (Chl-a, |ig I/1) and their ratios PC:PN, PN:PP, PC:PP,
PC:Chl. The vertical lines on the ratio plots depict nominal Redfield ratios of 6.6, 16, 106 and
50, respectively. The third figure shows the depth distribution of dissolved inorganic nutrients:
ammonium (NH4, jimol N L"1), nitrate (NO3, jimol N L"1), nitrite (NO2, jimol N L"1), dissolved
inorganic nitrogen (DIN, jimol N L"1), phosphate (PO4, jimol P L"1) and silicate (Si, jimol Si L"1)
and key ratios of NO3:PO4, Si:NO3 . Comparable distributions are shown from NODC World
Atlas data from the open Gulf of Mexico (NODC 1994). Vertical lines on ratio plots depict
nominal Redfield ratios 16:1 forNO3:PO4 and 1:1 for Si:NO3. The fourth figure shows the
depth distribution of dissolved organic carbon (DOC, jimol C L-l), dissolved organic nitrogen
(DON, jimol N L-l) and dissolved organic phosphorus (DOP, jimol P L-l) and ratios
DOC:DON, DON:DOP, DOC:DOP. Vertical lines indicate Redfield ratios 6.6, 16, and
106,respectively. The number of observations ranged from 1412 to 1628.
19
-------
Temperature (°C)
0 20
Salinity
35 36
DO (mmol O2 m"3]
37 0 100 200
300
100 -
200 -
300 -
NODC
Western
COM
- - - Hypoxia
NODC
Western
COM
400 J ' 400 J / 400 J
Figure 3-2-1. Depth Distribution of Temperature, Salinity, and Dissolved Oxygen.
20
-------
PC(MmolL1) PN(MmolL-1) PP (Mmol L1) Chl-a (|jg L')
5 10 0 1 20 0.2 0.4 0 50 100
100
200 •
300 -
PCPN PN:PP
1.1 1 10 100 0-1 1 1° 1°o 1000
PC:PP PC:Chl
10 100 1000 10 10° 100°
400
<50:1
Figure 3-2-2. Depth Distribution of Particulate C, N, P, Chl-a, and Ratios.
21
-------
NH4(MmolL'') NO3((jmol L'1) NO2(MmolL)
0 10 20 30 0 50 100 150 200 ° 5 10 0
0 i
100 200
300 -
100
200 -
300 -
0
100
200
r^-s— °BFU • ••
l%'
100*
9(10 - ,
NODC 300-
1994
300 -
400 * 400 -I 400 -I 400 -I '
PCMMmolL1) Si(MtnolL1) NO3:PO4 Si:NO3
0123 0 50 100 0.1 1 10 100 1000 0.1 1 10 100
IT"
100 \*»«« 100
•ft
200-
300
400-1
-NODC
1994
200 4m
300
400-H*
NODC
1994
100-
200-
300
400-I
100 -
200 -
300
< Redfield
400-I
< Redfield
Figure 3-2-3. Depth Distribution of NH4, NOi, NOs, DIN, PO4, Si, and ratios.
22
-------
DOC (|jmol L
DON fomol L"1)
0 500 1000 0 20 40 60
DOP (Mmol L'1)
0 2 4 6 8 10
100-
200-
.
8
300-
100-
200-
300-
200-
300-
400 -I * 400 J * 400 J
DOC:DON DON:DOP DOC:DOP
1 10 100 1000 1 10 100 1000 10 100 1000 10000
100-
200-
300-
400-J
100-
200-
300-
< Redfield
400-I
< Redfield
100-
200-
300-
400 J
< Redfield
Figure 3-2-4. Depth Distribution of DOC, DON, DON, and ratios.
23
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3-3. Transect-Profile Plots of Key Variables
This series of 8 figures summarizes the shelf wide distribution of key CTD variables: 1) Salinity,
2) Dissolved Oxygen (mg L"1), 3) Estimated Chlorophyll a (jig L"1), and 4) Estimated Total
Suspended Solids (mg L"1). CTD fluoresce and optical backscatter data were used to generate
estimated chlorophyll a and total suspended solids, respectively, using calibration factors
presented in section 3-4. Each panel represents an interpolated contour plots of each CTD
variables for each cruise, representing cross-sectional views of the shelf along each transect.
There are 2 figures for each variable, representing the eastern shelf (transects A through E) and
the western shelf (transects F through K). Transects X and M were omitted from this
presentation. Also shown are the locations of CTD stations along each transect, with numeric
labels depicting the bin averaged values used in the interpolations.
24
-------
Salinity
East Shelf
94'W 93'W 92'W 9TW 9Q'W B9'W
B
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007
GM0708
0.
0)
Q
Distance Along Transect (km)
Figure 3-3-1. Salinity Cross Shelf Profiles: Eastern Transects.
25
-------
Salinity
West Shelf
K
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006 J K^
GM0609
Apr 2007 V^
GM0704
Aug 2007
GM0708
•,!,.:;
-*
• ••:
k , *
cB;
94"W 93'W 92'VV 9TW 90'W 89'W
H
;. : "fe^iSH
Q.
(1)
Q
Distance Along Transect (km)
Figure 3-3-2. Salinity Cross Shelf Profiles: Western Transects.
26
-------
DO (mg L-1)
East Shelf
TN
28-N
94*W S3*W 92'W 91'W 90'W SS'W
B
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
.•.
Apr 2007
GM0704
Aug 2007
GM0708
4-1
Q.
Distance Along Transect (km)
Figure 3-3-3. Dissolved Oxygen (mg L"1) Cross Shelf Profiles: Eastern Transects.
27
-------
DO (mg L-1)
West Shelf
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007
GM0708
94"W 93'W 92'VV 9TW 90'W 89'W
a.
s
Distance Along Transect (km)
Figure 3-3-4. Dissolved Oxygen (mg L"1) Cross Shelf Profiles: Western Transects.
28
-------
Chl-a (MQ L-1)
estimated
East Shelf
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007
GM0708
TN
,
28-N
94*W S3*W 92'W 91'W 90'W SS'W
B
Q.
0)
Q
Distance Along Transect (km)
Figure 3-3-5. Chlorophyll a (ug L'1) Cross Shelf Profiles: Eastern Transects.
29
-------
Chi a (MQ L-1)
estimated
West Shelf
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007
GM0708
94'W 93'W 92'W 9TW 90'W 89'W
Distance Along Transect (km)
Figure 3-3-6. Chlorophyll a (ug L-l) Cross Shelf Profiles: Western Transects.
30
-------
TSS (mg L'1)
estimated
East Shelf
28-/V
94'W 93'W 92'W 91'W 9Q'W 89'W
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007 _.
GM0708 ,
0.
0)
Q
Distance Along Transect (km)
Figure 3-3-7. Total Suspended Solids (mg I/1) Cross Shelf Profiles: Eastern Transects.
31
-------
TSS (mg L'1)
estimated
West Shelf
Dec 2002
GM0212
Mar 2003
GM0303
Jun 2003
GM0306
Nov 2003
GM0311
Mar 2005
GM0503
Apr 2006
GM0604
Jun 2006
GM0606
Sept 2006
GM0609
Apr 2007
GM0704
Aug 2007
GM0708
94"W 93'W 92'VV 9TW 90'W 89'W
Distance Along Transect (km)
Figure 3-3-8. Total Suspended Solids (mg I/1) Cross Shelf Profiles: Western Transects.
32
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3-4. Water Column Integrated Bin Plots
The water column integrated variables collected during all surveys (2002-2007) were
summarized in the following series of histogram plots of identical structure. Each 4-panel figure
in the following section shows bin-averaged variables among the categories: 1) Cruise, 2)
Transect, 3) Bottom Depth Bin, and 4) Salinity Bin. The error bars are standard errors and the
numeric labels indicate the number of observations per bin. Figure 3-4-1 shows mean bottom
depth of the stations in each Depth Bin. Figure 3-4-2 shows Secchi disk depth at stations
occupied during daylight hours. Figure 3-4-3 shows diffuse attenuation coefficients (kd)
calculated as the log slope of PAR vs. depth at stations occupied during daylight hours. Figure
3-4-4 is the maximum Brunt-Vaisala Frequency (N, s"1) as a measure of stratification intensity.
Figure 3-4-5 is the pycnocline as the depth at which the maximum Brunt-Vaisala Frequency was
observed. Figure 3-4-6 is primary production (g C m"2 d"1) as water column integrated areal rates.
Figure 3-4-7 is primary production (mg C m"3 d"1) as euphotic-zone average volumetric rates.
Figure 3-4-8 is phytoplankton abundance (cells L"1) from surface water samples collected at
selected stations. Figure 3-4-9 is phytoplankton biovolume (|im3 L"1 X 106) from the same
surface water samples.
33
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Q.
0)
0
i
o
m
Q.
0)
m
Q.
O
Q
I
m
80
60
40
20
0
80
60
40
20
0
80
60
40
20
0
80
60
40
20
0
22
37
31
46
42
50
22
44
75
84
89
80
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
T
34
38
T
69
64
by
T
fiP
T
38
T
fiO
T
oc
OO
T
32 49 19
M
B
7R
D E F
Transect
H
210
123
76
K
135
a.
&
o
m
3-10
86
10-20
20-30
Depth
30-40
91
233
>40
212
0-18
18-27
27-32
Salinity
Figure 3-4-1. Bottom Depth (m).
>32
34
-------
u
u
0)
(/}
8
0)
w
14
12
10
8
4
2
0
14
12
10
8
6
4
2
0
14
12
10
8
6
4
2
0
14
12
10
8
4
2
0
45
36
27
15
45
18
38
22
44
38
36
44
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
29
31
50
33
59
17
38
27
32
22
26
12
M
-39-
B C D E F
Transect
H
141
73
48
K
87
s
3-10
75
10-20
20-30
Depth
30-40
62
153
>40
118
0-18 18-27 27-32
Salinity
Figure 3-4-2. Secchi Depth (m).
>32
35
-------
2.0 -I
1.5 -
•o 1.0 -
0.5 -
n n
T T
^^^^~
1 8 33 <^3 I 48 I 1 4^ I 1 — x — 1 4^5 I
I II II 46 I I
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
1.5 -,
1.0 -
0.5 -
n n .
T
T
15
16
T
T rJ-i
X
M
D E F
Transect
H
3-10
10-20
20-30
Depth
30-40
K
2.0 -,
1.5 -
1.0 -
0.5 -
n n .
T
27
95 5£ 13 4S
1 1 1 1 1 ™ 1
>40
2.0 -,
1.5 -
•o 1.0 -
X
0.5 -
T
13
43 1T5 83
0-18 18-27 27-32
Salinity
Figure 3-4-3. Diffuse light attenuation coefficient (kd, nr1).
>32
36
-------
0.20
0.15
LL
m 0.10
x
TO
S 0.05
0.00
X
(0
£
m
21
37
31
46
22
42
44
75
84
89
80
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
0.20
0.15
0.10
0.05
0.00
0.20
0.15
0.10
= 0.05
0.00
0.20
0.15
LL.
m 0.10
x
TO
^ 0.05
0.00
20
33
64
56
53
63
38
54
36
55
32
XMABCDEF
Transect
H
3-10
10-20
20-30
Depth
30-40
35
91
233
0-18 18-27 27-32
Salinity
Figure 3-4-4. Maximum Brunt-Vaisala Frequency (s"1).
48
19
K
68
194
116
69
124
>40
212
>32
37
-------
40
30
I 2°
^ 10
0
14
36
30
38
38
41
74
83
86
71
o
I
0.
25
20
15
10
5
0
30
25
20
15
10
5
0
25
20
o 15
I 10
Q.
5
0
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
T
19
28
62
56
53
58
32
50
33
49
31
42
17
M
o
I
a.
A B C D E F
Transect
G H I
179
111
68
K
121
3-10
30
10-20
20-30
Depth
30-40
87
215
>40
198
0-18
18-27
27-32
Salinity
Figure 3-4-5. Pycnocline Depth (m).
>32
38
-------
3 -,
a 2-
£
Q. 1 -
a.
n .
23
T
32
T T 1 T 1
36
T
56
69
T
59
66
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
a 2-
£
n
&
n -
T
3 -i
a 2-
£
0.' 1 -
a.
n •
19
X
T
91
M
T
35
3 -I
a 2 -
£
o.1 1 .
a. '
n .
T
31
A
3-10
T
46
T
35
B
T
29
C
133
10-20
T
T r^~i T T r^— i
30
17 32 26 30 23 29 19
D E F G H 1 J K
Transect
T
71 46 56
20-30 30-40 >40
Depth
44
130 121
0-18
18-27 27-32
Salinity
>32
Figure 3-4-6. Areal Primary Production (g C m~2 d"1).
39
-------
400
300
> 200
^ 100
0
400
300
200
100
0
o
:•
0.
23
32
36
56
69
59
68
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
T
|
1 Q
T
21
T
31
, , , , , T
35 29 1-36-1 19 I 32 I ,-3§-| |-3©-, 23 29 19
400
300
> 200
°- 100
0
400
300
>, 200
Q.
°~ 100
0
M
3-10
B
D E F
Transect
H
K
35
T
133
n
T
46
T
I - I
10-20
20-30
Depth
30-40
>40
T
46
44
130
123
I I
0-18
18-27 27-32
Salinity
>32
Figure 3-4-7. Volumetric Primary Production (mg C m~3 d"1).
40
-------
4000
= 3000
3
< 2000
£ 1000
0
c
.a
15
13
28
43
32
17
26
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
8000
c 6000
.a
<
4000 -
2000 -
n .
T
6
T
31
T
23
I"*! p32! JJL 18 rJinr^-1I-U-II-L2-ir§1
5000
4000
c
5 3000
-^ 2000
£ 1000
0
M
A
B
D E F
Transect
H
3-10
10-20
20-30
Depth
30-40
0-18
18-27 27-32
Salinity
K
3000 -I
2500 -
2000 -
1500 -
1000 -
500 -
n .
T
35
T
77
T T T
37 16 38
Figure 3-4-8. Phytoplankton Abundance (cells I/1).
>40
T
27
33
89 54
>32
41
-------
6 -
5 -
4-
3'
2-
1 -
r±i
15
13
28
32
17
26
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
5
T
31
23
20
32
18
T
15
JL
11
12
m
6
5
£ 4
3 -
2 -
1
0
M
3-10
B
D E F
Transect
H
10-20
20-30
Depth
30-40
>40
0-18
18-27
27-32
>32
Salinity
Figure 3-4-9. Phytoplankton Biovolume (um3 ml'1 X 106).
K
T
35
T
77
T
37 16 36
II
*-»-?
I I
T
33
T
89 54
I I
42
-------
5-5. Stacked Water Column Integrated Bin Plots
The following 2 figures describe the water column with respect to density and light structure. As
in the prior set of plots, each 4-panel figure shows bin-averaged variables among the categories:
1) Cruise, 2) Transect, 3) Depth bin, and 4) Salinity bin. The error bars are standard errors and
the labels indicate the number of observations comprising each bin. Figure 3-5-1 shows the
surface mixed layer (open bars) and bottom layer (shaded bars) bin averages, as delineated by the
pycnocline, calculated as the depth at which the maximum Brunt-Vaisala Frequency was
observed (see Figure 3-4-5). Figure 3-5-2 shows the euphotic layer (open bars) and the aphotic
layer (shaded bars) zone at the subset of stations occupied during daylight hours. The euphotic
layer boundary was assumed to be the 1% light depth, calculated as 4.61/kd and/or 1.4/Secchi
depth (see Figures 3-4-2 and 3-4-3).
43
-------
60
50
| J°
1 20 H
° 10
0
60
50
-§ 40
r 30 ^
£• 20
1
4
T
1
T
1
36
T
1
30
i-S-i
J-
1
38
T
s
38
-I-
41
-i-
74
— I—
83
I i 1
86
i 1
-±-
71
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
10
0
T
1
1
19
I i i
28
T
1
62
T
1
-z-
56
.
53
T
1
-i-
58
-
—
32
-T-
50
33
.
49
^T
42
Tr
X
M
100
80
1 60
f. 40
a>
Q 20
DEF
Transect
H
3-10
10-20
20-30
Depth
30-40
0-18
18-27
27-32
>40
>32
Salinity
Figure 3-5-1. Surface Mixed Layer and Bottom Layer Depths (m).
K
1 ^ 1 1 -IT,-, 1
I 51 1 1 I7y 1
LLJ 1
68
T
121
DU -
-§ 40 -
£ 30 -
+J
Sr 20 •
° 10-
n .
D Surface Layer
D Bottom Layer
_
T
30
87
215
198
44
-------
60
50
E 4°
r son
g- 20
10
0
80
60
£40
Q.
0) ori
Q 20
36
i
18
22
44
38
36
-*-
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
dh
33
59
17
t
27
32
22
12
X
100
80
-=- 60
£ 40
I 20
0
-20 J
60
50
-§ 40
£ 30
g- 20
Q .„
M
DEF
Transect
H
Depth
DEuphotic Layer
DAphotic Layer
118
K
__ I 141 I
| TO | | I4I |
3-10 10-20
73
20-30
1
48
30-40
87
-'•
>40
0-18
18-27 27-32
Salinity
>32
Figure 3-5-2. Euphotic Layer and Aphotic Layer Depths (m).
45
-------
3-6. Vertically Binned Water Column Bin Plots
The following series of 28 vertically-binned histogram plots are of identical structure. As in the
prior plots, each 4-panel figure shows bin-averaged variables among the categories: 1) Cruise, 2)
Transect, 3) Bottom Depth bin, and 4) Salinity bin. However, this set differs from prior plots in
that each category was further split into surface layer (open bars), mid-depth (hatched bars), and
bottom layer (solid grey bars) bin averages. The error bars are standard errors and the labels
indicate the number of observations comprising each bin. The first 5 figures include the
hydrographic variables from the CTD. CTD variables were measured at high frequency
throughout the water column, however these plots only include the values matching the depths
where discrete water samples were collected. The discrete variables were derived from
measurements on water samples collected from the Niskin bottles (see Methods). Two figures
bear further explanation. Figure 3-6-7 represents estimated chlorophyll derived from CTD
fluorescence data scaled to chlorophyll a units using regression relationships shown in Figure 3-
8-1. Similarly, Figure3-6-9 represents estimated TSS derived from CTD optical backscatter or
beam attenuation data, scaled to TSS units using regression relationships shown in Figure 3-8-2.
46
-------
30 -
25 •
Q.
E
o
H 20 -
-1C .
fl
B
fl
40
1
•
4C
0212 0303
^.
i
33
X.
51
JL
33
4'
7 45
48
252
322
-Hi
Leo
R
0306 0311 0404 0503
r-|
46
-j
20
r— ,
_^
45
82
-,
38
74
0509 0604 0606
8
X.
72£
95
K
23
_.
30
85
T
4
0609 0704 0708
Cruise
30 -I
25 -
a.
E
H 20 -
1C; .
JL
20
fi
/
X
LJ. T
21
37
I
17
33
M
JL, r^i
T i-
66
=1
36
pE.
55
50
T-r^i
45
56
59
i
11 54
1
59
JL.
50 55
X.
9
29
ABODE
~
41
58
.X.
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44
53
39
F
.X.
I
21 3
6
X.
58
52
G H
x-
56
A
34
JE
rs:
2
JL
49
XL
29
J
JL.
49
.X
T
2
19
K
Transect
30 -
25 -
a.
c
H 20 -
15 -
i
70
69
T
69
3-10
212
199
199
125
i
116
116
T
70
10-20 20-30
72
72
30-40
1
33
125
125
>40
Depth
30 -
Q.
H 20 -
15 .
D Surface
DMid Depth
D Bottom T
T
40
T
8
10
98
T
„
26
250
75
• — i — .
77
222
308
468
0-18 18-27 27-32
Salinity
Figure 3-6-1. Temperature (°C).
>32
47
-------
40 -i
30 -
20 -
10 -
n .
*|
22
B_
42
20
.X
40
88
40
JL
33
pZ.
51
-j-
33
-t
47
_i_
45
S-
48
.X
25
.1
28
JL
22
pX
48
-Ki
60
,JU
43
pC
46
20
45
82
^
38
^
74
r-
87
26
86
r^
95
_.
23
90
—
85
I — |
4
80
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
40 -I
30 -
« 20-
w
10 -
n -
1
20
_L
7
21
I
17
JL
33
^
36
~
36
35
30
~
45
56
._
59
~
41
54
,-
39
^K
30
^
35
-
39
29
41
,-
58
^Si
44
__
53
—
39
21
36
~
58
32
56
-
34
=•
12
33
—
49
29
49
p
22
_i_
2
™
19
XMABCDEFGH I JK
Transect
125
116
116
70
72
72
133
125 125
3-10
10-20
20-30
Depth
30-40
>40
40
30
« 20
32
48
-------
25 -i
20 -
15 -
H
*» .,,•.
w 10-
5 -
n
u
1 T v
pZ
22
-^
42
20
X
40
i^Ei
88
40
•rt
JL
33
51
JL
33
jX
47
JL
45
.JO.
48
JL
25
JL
28
JL
22
-L.
48
.z
6C
JL
43
JL
46
20
=1
45
z.
32
_^
38
iM.
74
87
-i
2£
r— i
;86
=•
95
_^
23
90
"•
85
"•
4
^
80
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
25 -I
20 -
w 10 -
5 -
n -
T^ ^fa ^h — — _a
X
20
j_
72
1
^
r
I
17
JL
3^1
E
56
n
-
36
35
|
30
n
n
45
56
Jl
BI
.
415
4
=
39
SO
35
"•
39 2
r ^
941
=
58
44
53
^Si
39
^
21
36
^^
58
32
^B.
56
^
=
34
232
4£
-K
2c
T
49
-^
22
_i_
2
19
XMABCDEFGH I JK
Transect
25
20
15
10
5
0
25
20
15
10
5
0
70
69
3-10
69
212
199
199
125
-r
116
116
70
72
72
133
d
125
10-20
20-30
Depth
30-40
>40
IH Mid Depth
D Bottom
i — ^^ — i sf °nn
1 1 1 1
98
31
26
250
§
78
##
77
I
222
308
w/,
468
0-18
18-27 27-32
Salinity
Figure 3-6-3. Sigma T (kg m 3).
>32
49
-------
300 -I
200 -
0
a
100 -
n -
n^r
22 42
42 20
40
r~i
a^
38 40
^.
3351
^1 4-
J2
"i,.
7 45 48
A
3
25
2
8
22
pi
48
SO
1
43
0212 0303 0306 0311 0404 0503
r-.
46
^]T
20 45
K
82
X. ~
38
T >< 26
'A 8
3
-,
95
X-
r— i
85^
4 80
0509 0604 0606 0609 0704 0708
Cruise
300 -I
j
200 -
O
a ?
100 - 2
0_
L
^
0
7 21
_3
371?
3
33
K.
36
35
n n
30 45
59
3
bol
n
54
39s
C|
X.
0
35
X M A B C D
•
3
B
929
E
3^
41
_
58
^^ r~
44
3^
53
3921.
Ej
6
58
52 -c 3412
55
-1-1 ^J-
X.
33
49
_
29
49
^
222
19
F G H J K
Transect
300 -i
200 -
O
100 -
n -
70
69
*^T^
69
212
%
199
199
125
3-10 10-20
116
116
20-30
70
72
72
133
124
124
30-40 >40
Depth
300 -I
200 -
0
a
100 -
n .-
—
T
40
-IT T
w
8
10
98
31
26
D Surface
DMid Depth
— I — ~ — | D Bottom
250
78
77
222
308
467
0-18
18-27 27-32
Salinity
>32
Figure 3-6-4. Dissolved Oxygen (mmol Oi m"J).
50
-------
140% -i
120% -
100% -
*- 80% -
o 60% -
° 40% -
20% -
n% -
— i
X.
22/n
42 20
r-l
40
^
38
40
f
33
^
51
^^ ^
32
>745
48
3
25
2
3
22
48 so
43
A
46
1
20
I
45
j3S^
82
^-, n
38
E_
8
4
7
86
95
X.
90
85
L
4 BO
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
120% -|
100% -f
80% -
8 60% -
0 40% -
20% -
n% - -
L
T
^
c
7
21
X.
x.
371?
33
X M
120% -i
1 00% -
80% -
"S
"* COO/
U) OU/o -
0 40% -
20% -
no/ _
_
70
69
D
-,
36
A
69
3-10
120% -,
100% -
80% -
+^
$ 60% -
0 40% -
20% -
n% .-
D Surface
Cruise
~
3
DC
1
5 I*
1
|=i
—
E!
n
54
C.
=,
0 3
3£
=
92c
41
58
B C D E
Transect
212
199
199
125
_
116
r™i
=
44
3
39
F
116
10-20 20-30
Depth
DMid Depth
• — i — ,D Bottom
40
T
II
T
10
98
T
31
T
26
.
'13
c,
6
583
^
2
5£
3412
3
49
^
?c
G H J
70
72
7?
133
I=1T
22
^
2
1£
K
,»
124
30-40 >40
250
^
^ff
78
^
"L^
77
222
32
Figure 3-6-5. Dissolved Oxygen Percent Saturation.
51
-------
o
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
M
K
12
10
8
1 6
° 4
2
0
T T
80
78
T
78
— * — z T
224 213 213 131 -r?5-n25~| 77 JZ9.-?e-| ITsT! 135 135
3-10
10-20
20-30
Depth
30-40
>40
12
10
8
1 6
o
T
91
DMid Dep
D Bottom
T
th
T
95
x/x^
30
T
25
245
74
77
220 301 I 4?H I
i I I I
0-18
18-27
27-32
>32
Salinity
Figure 3-6-6. Chlorophyll a (Chi, ug I/1).
52
-------
<
£
O
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
X
M
K
12 -
10 -
w 8 -
< 6 '
1 4-
2 -
n -
T
70
T
69
fip
T
212
3-10
199
10-20
199
T T
125
117 117 72 ^?9- 73 133 425-TT2T
20-30 30-40 >40
Depth
D Surface
1P .
10 -
13 8 -
<' 6 •
•= 4 -
0 4
2 -
n -
DMid Depth
D Bottom
T
42
T
T
11
T
12
98
T
T
/y
31
26
222 i 380 468
0-18
18-27
27-32
>32
Salinity
Figure 3-6-7. Chlorophyll a - Estimated (Chle, ug I/1).
53
-------
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
50 -
40 -
W 30-
w
I- 20 -
10 -
0
I
24
I
32
|6|
X M A B
D E F
Transect
H I
K
50
40
30
20
10
0
T
66
54
T
54
T
r4&4-|1l1 111 111 63 |~63| 62 3_8 . Tti . 9
3-10
10-20
20-30
Depth
30-40
50 -
40 -
W 30 -
w
I- 20 -
10 -
n .
T
88
8
T
55
DMid_Depth
D Bottom
T
T
• 7-1 |__ S_ 16 207 . 1€ 42 158 99 i 2TO j
0-18
18-27 27-32
Salinity
>32
Figure 3-6-8. Total Suspended Solids (TSS, mg I/1).
54
-------
20 n
15 -
10 -
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
XMABCDEFGH I
K
(/}
w
20 -,
15 -
10 -
5 -
T
T
Co
T
64
64
T
1 — z — 1 — 1 SR , - , —
197 T§6~ 122 114 114 71 72 72 132 124JT2T
3-10
10-20
20-30
Depth
30-40
>40
20 -,
15 -
+j
TO
•=, 10 -
^ 5 -
D Surface
DMid Depth
T
40
T
yf^
T
10
D Bottom
T
86
25
25
73
222 299 452
0-18
18-27 27-32
Salinity
>32
Figure 3-6-9. Total Suspended Solids - estimated from CTD OBS sensor calibration against
empirical data (TSSe).
55
-------
100 -i
80 -
s 60 -
O1 40 -
Q.
20 -
n -
100 -i
80 -
g 60 -
O1 40 -
Q.
20 -
n -
100 -|
80 -
g 60 -
3.
Q' 40 -
Q.
20 -
n -
100 -i
80 -
g 60 -
3.
O1 40 -
n
on
^u •
n .
I
0212
16
X
T
70
T
85
JL
34
o:
35
M
69
3-10
I7r
(03
I
b
T
q
fihf\
. ft _ I 50 H
T ^ t-j 42 T
0306 0311 0404 0503 0509
Cruise
f\ ft fl
"5fl6^58p^51f^flp|sp|5/28
A B C D E F
Transect
L
T*
9 ,
I96 125 119 119
10-20 20-30
Depth
T
I T
T
62 79 ///£ 22
1j
223
JL F| ft ,
0604 0606 0609 0704 0708
i T JL
5'^f^34633f^^19
G H I J K
T
74 -T7-| 77 | 130 43?^
30-40 >40
D Surf ace
D Mid_Depth
T 68
41
I 2T4 2T2 436
0-18
18-27 27-32
Salinity
>32
Figure 3-6-10. Particulate Carbon (PC, umol I/1).
56
-------
14 -i
12 -
10 -
S 8 -
a.
z
°- 4 -
2 -
n -
14 -i
12 -
10 -
S 8 -
5 e-
Q. 4.
2 -
n -
14 -i
12 -
10 -
^1 c
^ "
n A
o. 4 .
2 -
n -
14 -i
12 -
•i n
I U •
S 8 -
3 6 -
z
n j
4 -
-
n .
T TJ.
T r1! 47 43 50
0212 0303 0306 0311 0404 0503 050
Cruise
1 jJLl T
-h JL -r r1
X M A B C D E
Transect
1 HH
-
70 68 68 T
ww , „- ^
201 195 195 <0, ^^
| 195 123 119 11
3-10 10-20 20-30
Depth
T T
T
T T
_L_. T
-L «, 79 ^
85 fffi \ -i c oo
OJ 15 22
29 22
I
52
9
I
28
F
9
'0
I
,1. fl i ^JL^ ^ F,
0604 0606 0609 0704 0708
IT _
I &
G H J K
-^
74 -TO-I 76 I 123 445-TfT2~
30-40 >40
D Surface
D Mid_Depth
T
T
41 207 -res- 419
0-18
18-27 27-32
Salinity
>32
Figure 3-6-11. Particulate Nitrogen (PN, umol L"1).
57
-------
1.4
1.2
1.0
0.8
1 0.6
0.4
0.2
0.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
232022
42
50
ft
50
22
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
4C17
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
X
M
D E F
Transect
H
K
77
T
78
78
_ T
220
207
T
207
1 1 ?7 1 1 20 120 1 75 1 ~Z& i 70 i , 1 36 , 1 24 , 1 24
II I I I I I I I I
3-10
10-20
20-30
Depth
30-40
>40
87
T
30
62
94
18
25
236 49
74
D Surf ace
D Mid_Depth
D Bottom
208 219
0-18
18-27 27-32
Salinity
>32
Figure 3-6-12. Particulate Phosphorus (PP, umol L"1).
58
-------
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
X M
3-10
10-20
20-30
Depth
30-40
K
T
73
I
70
T
70
200
T
194
T
1 CM
rr5o~ 121 -m-i r~7b~ 70 ^fe-i rr^s- 105 ToVi
>40
5
4
I 3
i 2
1
0
81
81
18
I
19
D Surf ace
D Mid_Depth
D Bottom
225
65
73
236 415
0-18 18-27 27-32
Salinity
Figure 3-6-13. Ammonium (NH4, umol L"1).
>32
59
-------
1.6 n
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
XMABCDEFGH I
K
1.6
1.2
S 0.8
z
0.4
0.0
1.6
1.2
O °-8
z
0.4
0.0
65
64
171
183
102
1 02
68
68
3-10
10-20
20-30
Depth
30-40
>40
D Surf ace
D Mid_Depth
D Bottom
T
74
T
36
T
58
T T
72
^
T
19
I-1"-
y
58
65
117
222
T
394
0-18
18-27
27-32
>32
Salinity
Figure 3-6-14. Nitrite (NO2, umol I/1).
60
-------
40 n
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
X
O
40 -,
30 -
20 -
10 -
n .
54
i
rrfl
8
34
±9.5
L
14
1
31
Jl
^$^F^f^2^f^22^4^2622429^ 172U
X M
B C D E F
Transect
H
K
40 -,
30 -
20 -
10 -
n .
T T T
T — —
3o 182 152 1 i 0*7 i 06 i 98 r~9o~| 56 • 56 • 78 I 1 32 1 1 22
3-10
10-20
20-30
Depth
30-40
>40
X
O
40 -,
30 -
20 -
10 -
n .
T
70
D Surfs
DMid
DBottc
T T r^-l rJLn
T '
7r T . ,-
31 54 '3 17 ID 17n . rm , fift 111
J ' 1 / 1/U 33 OU I 1 OO r
0-18
18-27
27-32
>32
Salinity
Figure 3-6-15. Nitrite + Nitrate (NOx, umol L'1).
61
-------
60 -
40 -
20 -
n -
0212
JL JL ,TT r1! A
i^
^i r nri r^
i n *^D T1 ^^^ ^ 1 1 -| i ^" "« 4o 4o ^ ^ 1 1 ^^^ I |
iy 49 1 1 1 1 ^ en \Af\ "*" 1 1 81 — | ™ | — . ^_ Ind 1 ^1 ^, 1 "^i
K4J43|46| 523453 \ 20r^ 37^74 87pq8a eq90 [lq 12
IIII IIII I I I I I I I I I I I I I I
0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
74.6 ± 10.4
60 -
40 -
20 -
n -•
\f.
zffl
X
60 -
40 -
20 -
n -
T
70
60 -
A n
"
20 -
n .
83
3^
v
_L
20
3f
JL
3 FI _ __ -.=1^ .=1=^ j^ ri
D658p2 1584856 543649 lecffl 332935 PT'H StSpT] Q2^ ^SV?^ WW R^l
111 iiii i__i__i__i_n_i__n_i_i__i__i__i_n_i__n_i_i__i__i__i_i__i__i__i
MABCDEFGHIJK
Transect
-r T - T
68
. _ . K -r-
191 102 98 ~9T"| 58 59 ~5T"| 112 106 106
3-10 10-20 20-30 30-40 >40
Depth
D Surface
D Mid_Depth
D Bottom
T I
T -r —^-[
T
39
63 82 iy i — - — i — - — i — - — -
204 58 66 i 171 242 374
0-18
18-27 27-32
Salinity
>32
Figure 3-6-16. Total Dissolved Nitrogen (TDN, umol I/1).
62
-------
25 -i
20 -
15 -
z
o in
Q 10 -
5 -
n -
X
12
i
'*i
XX
10
20
iX
41
_ ,.
3837
0212 0303 0306 031
25 -i
20 -
15 -
z
Q 10 -
5 -
n -
JL
2719
X
25 -i
20 -
15 -
§ 10-
5 -
n -
T
,1,
27
2i
1
12
JL
27
M
T
57
25 -i
20 -
15 -
§ 10-
5 -
n .
60
T
16
1
A
^
60
3-10
T
68
44
48 4
fl
B
I T- | T
170
I
1
39
8
T
T T
14
_l_
12
xT~\ JL
F^l d. =• r"i r1! r1!
43 oir -r- T -r _
47 tc in 45 ob x\ QR r~i -in -19
26 B5 26 85 r"f™l
II 1 1 1 1
1 0404 0503 0509 0604 0606 0609 0704 0708
JL.T
38
'-53
c
167
i
167
10-20
28
52
i
60
T
,.
Cruise
JL
.1
48 3
•n JL T
T -X.T T r" T r^ T r^ ^ p^i
45 302831 *9M49 C^2g 39'840 QlLJ 37 37 ig4J
D E F G H J K
Transect
T
-r -i- ~~* a^~ T
88 94 94 49 51 51 95 77 77
20-30 30-40 >40
Depth
D Surface
DMid Depth
D Bottom
T
_ —
M 177 48 59 154 196 324
0-18
18-27 27-32
Salinity
>32
Figure 3-6-17. Dissolved Organic Nitrogen (DON, umol L"1).
63
-------
50 -
40 -
30 -
20 -
10 -
n -
_rl
JL^j
E3r4P
r 1 1
0212
100 -i
80 -
60 -
40 -
20 -
n -
d,-
rff
i i r
X
50 -
40 -
30 -
20 -
10 -
n - -
T
65
50 -
40 -
30 -
9n .
10 -
0 -
T
o4
^
_J_
.
35.
pZ
B
g32
0303
]
I
I
]
32
1
4 33
^
L
P
M
T T
63
63
3-10
T
j_
31
T JL
T
X
0306
1
t
V
1=1 r
fl
1 1 1
A
1
j
4
L
°28
031
— i ._.
340
r i
B
185
T
18
-r
43
X
X i-rir1! r1!
47 43 -L ,Jt T
19 502352 46^45 79-n Cm 88 Pi Q ^
I I I I I I I I I I
1 0404 0503 0509 0604 0606 0609 0704 0708
4
:29
C
2
-p.
r"i
44
182
10-20
T
T
H
0-18
6
1
r
72
1
T
Cruise
EC
,|
5C58 ggz3|32| 543551 EoRgtel Ba28|5o| 26 5& |4q26|48| FW-M
n n i n i i n i \ \ \ \ n_i_i__n_i__i_i__i__i__i
D E F G H I J K
Transect
106 101 101 60 63 63 118 110 110
20-30 30-40 >40
Depth
D Surface
T riMiH Donth
14
D Bottom
17 _ . — = —
nn 6° -
191 50 °^ 04c -570
187 245 379
1 '
18-27 27-32 >32
Salinity
Figure 3-6-18. Total Nitrogen (TN, umol L'1).
64
-------
1.4
1.2
1.0
0.8
0 0.6
0.4
0.2
n n
u.u
n
jj
P371S
I22
T T
jr jJ-JL _
^f] JL T T T n jjnl r1 4 30
^|24| |^|4lp| 454547 8 14^ |J^41 ^ ™ ^ ^^ |^| fl*86 |^| |s4
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
1.4 -|
1.2 -
1.0 -
*. 0.8 -
? 0.6 -
U.
0 4 •
\j .T^
0.2 -
n n
1.7 ±0.2
JL.
— T
r~|
B4p135
| |
IT
33
A r1]
1332 ^
58 r1 54 r1^ ^.[^1 jj1!
p7re ISI*6 68|40PH l?5B8p^ eflsQ BrlTiM iSsffTSs] iSS^S *Hi^o| ifSi^Sl iSTlisI
r 1 rT pjoptj— ' | | ojJOj i pTjiop^ " P P | Y\ P"J jJJj^JJJ^j prrjaLjji^ pto| optj |^z| | ^
XMABCDEFGH JK
Transect
1.4 -i
1.2 -
1.0 -
*. 0.8 -
g 0.6-
0.4 -
0.2 -
n n
u .u
T -I_^L^^ ,. , .^b.
74
70 70 205 200 200 ^_ 123 123 .-^ 76 76 pB8- 129 129
I I I
3-10 10-20 20-30 30-40 >40
Depth
1.4 -
1.2 -
1f\
.0 -
* 0.8 -
g 0.6-
0.4 -
0.2 -
0.0 -
D Surface
DMid_Depth
• Rnt+nm
oc
oD
T T
T T
80 18 19 p-252- 65 73 .-246- 278 445
i i i
0-18 18-27 27-32 >32
Salinity
Figure 3-6-19. Phosphate (DIP, umol I/1).
65
-------
1.0
0.8
0.6
Q.
° 0.4
0.2
n n
I
23
X.
14
i
19
0212 0303
1
30
T
X
49
32
0306
T
14
T
J_.
43
031
T
46
1
TI
24
I
28
I
22
T
i
48
60
0404 0503
I
_l_
51
T
L
33
T
53
JL
46
20
JL.
JL
45
86
0509 0604 0606 0609 0704 0708
Cruise
2.5 -i
2.0 -
1.5 -
Q.
° 1.0 -
0.5 -
n n -
JL
T- T -^
ns
32
^ ^
L
20
pL
34
X M
(
1
1
A
~i
^
r
H
H
B
=1
1
ft
*
c
]
^.
524
^^-
348
D
Iff
1
3
F
E
ffl
F
F
11
° ^fl ^ ^f| pfijT]
G H J K
Transect
1.0 -I
0.8 -
0.6 -
n
£ 0.4-
0.2 -
n n -
T
T
64
T
62
62
3-10
T
156
T
y/A
149
^
149
76
10-20
^
76
1
r
1
76
_ T
46
20-30
i T
46 46 07 87
90
30-40 >40
Depth
1.5 n
1.0 -
Q.
Q
H 0.5 -
n n .
T
76
T
38
6?
L_
n
n
66
T
26
15
171
D Surface
DMid_Depth
• Rnttnm
OULLUI 1 1
T
58
en
~ 91 Q 293
119 219
0-18
18-27 27-32
Salinity
>32
Figure 3-6-20. Total Dissolved Phosphorus (TDP, umol I/1).
66
-------
0.8
0.6
O 0.4
Q
0.2
0.0
0.8
0.6
O 0.4
Q
0.2
0.0
I
12
25
41
25
42 42 44
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
1°'4
40 4635
235
44
38
26
3
XMABCDEF
Transect
H
K
0.8 -
0.6 -
O 0.4 •
0.2 -
n n -
0.8 •
0.6 •
Q. - .
O 0.4 •
Q
0.2 •
On .
T
T .-JL-. T
58 54 °* 131 131 131 65 71 71 40 44 44 g3 ?4 ?4
3-10 10-20 20-30 30-40 >40
Depth
D Surface
DMid_Depth
T D Bottom
j I
68 n 45 ~
32 55 47 Vj|>3 9 152 44 no 190 265
0-18 18-27 27-32 >32
Salinity
Figure 3-6-21. Dissolved Organic Phosphorus (DOP, umol L"1).
67
-------
1.6
1.2
£ 0.8
0.4
n n
3.0 -i
2.5 -
2.0 -
Q. 1.5 -
i-
1.0 -
o *> -
n n -
1.6 -
1 9 -
Q- no
p 0.8 -
0.4 -
n n -
.6 -
19-
5: 08-
.4 •
On -
2
P
r
cf^1
3 44
D21
tf
T
X
T
7fi
1
8
ft,
21
2
i
1
r
6
Aft film h
T T 50 _ T -rrii rii
^ _l_ ^ ^ ^^^ CQ T | |
0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
r
¥l
36
6874 j3| pB^] 58p|^| f$^\ p6p^ ^STp5] p|fflp| pB^e] p2pp| (4^4^ ^?|l^
MABCDEFGH JK
Transect
T
-^ - T T
-X—-3—
72 r^n _
126 123 123 76 78 78 pf^p 127 127
5-10 10-20 20-30 30-40 >40
Depth
_ T nSurfarp
T DMid_Depth
T T D Bottom
1 1 1 -r
eo - r^
ff m
-,n ,23 _
30 «c 32
Salinity
Figure 3-6-22. Total Phosphorus (TP, umol L'1).
68
-------
25 -i
20 -
15 -
K 10 -
5 -
n -
u
T
T
i TT T T ,1] [\[ fTl
-irfl
17
20 37
I
n JL m1!™! x40 *! i fllf1! fxlrx48o
_- yp~24 .. 45 33 T T- r1] r^1 86 T P"
60 24 Q38 36 45 6 13 59 52 D^Q 81 T74 86 26 95239°84
ii r 1 1 1 1 1 1 i
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
60 -
50 -
40 -
W 30 -
20 -
10 -I
n
I.
i0
A
1431^p|f.fl^pp^3^^^p^
XMABCDEFGH JK
Transect
20 -
15 -
W 10 -
5 -
n
T
T r
72
i
T
1 T
T | 1 , T
67 c_
67 196 197 197 T 103 T
117 123 71 76 133 128 128
3-10 10-20 20-30 30-40 >40
Depth
35 -i
on
OU •
25 -
20 -
W 15 -
A f\
10 -
5 -
0 -
T D Surface
O/"*
86
DMid_Depth
_ D Bottom
-L-rh
1Q fifl rn •"•
oy ou 7Q ig 19 _
pTT 59 67 ^ 213 278 445
i i i
0-18 18-27 27-32 >32
Salinity
Figure 3-6-23. Silicate (umol Si I/1).
69
-------
500 -i
400 -
300 -
o
§ 200 -
100 -
n -
i _
0212
600 -i
500 -
400 -
g 300 -
Q 200 -
100 -
n -
"ffi
X
0303
JT.
.j
10
M
I,
24
r1!
44
0306
1ft
I
E
A
0311
-P
26
B
T
44
h
F
34
X
31 2
L
7 -a
5
^
234
_j
53
ftTl r1!
461944 Hl3 ft0 QrQ R R
I P i II r 11 r Pin I I I I
0404 0503 0509 0604 0606 0609 0704 0708
5
c
^j.
351
Cruise
_i
4^tar
D
E
-L
r7-!
14
T _
I. r^j pi ^1 JBJ
3^| 2510^|28|8|28|252^|32 32J |16^
F G H I J K
Transect
400 -|
300 -
g 200 -
Q
100 -
n -
T
48
400 -i
300 -
g 200 -
Q
100 -
n .
T
72
'
1
1
I
43
144
3-10
35
_x_
58
r
139
139
80
10-20
T
54
I
rjfj
%
w*
^
^^
T
w
75
T . T .
75
20-30
Depth
10
46 47 47 83 79 _,g
30-40 >40
D Surface
142
T DlVlid D^nth
D Bottom
15
41
133 114 274
0-18
18-27 27-32
Salinity
>32
Figure 3-6-24. Dissolved Organic Carbon (umol C L"1).
70
-------
2300 -i
2200 -
2100 -
0 2000 -
° 1900 -
1800 -
17DD -
0212 0303
0306
031
f
1 0404
5
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81 34"
r—
1 26
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36
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23
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84
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480
0509 0604 0606 0609 0704 0708
Cruise
2300 -i
2200 -
2100 -
0 2000 -
° 1900 -
1800 -
17DD -
X
7
32
X
?3
JL
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=
5
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2£366
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31 2
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Transect
2300 -i
2100 -
0 2000 -
° 1900 -
1800 -
1 7DD -
n
49
T
33
3-10
33
163
138
138
102
10-20
. x.
•p
86 86
I
I
60
_,_
52
52
89
75
75
20-30 30-40 >40
Depth
2300 -i
2200 -
2100 -
0 2000 -
° 1900 -
1800 -
1700 -
D Surface
D Mid_Depth
_l^_^_
63
YJ
I
T
12
•
T
56
0-18
T
%
D
T
13
Bottom T
i — ' — i — = — . i
1
18-27
182
J
45
16
-rn
vyyfl
2 96 314
I
1
27-32 >32
Salinity
Figure 3-6-25. Dissolved Inorganic Carbon (umol C L"1-).
71
-------
25 -i
20 -
15 -
10 -
5 -
n -
0212
25 -
20 -
15 -
10 -
5 -
n -
T
23
X
9
X
25 -i
20 -
1 ^
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10 -
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67
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I
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67
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197
3-10
T
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24z8i fltem flfffi82$83fl
1 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
T
pi,
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54
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CDEFGH I JK
Transect
189
T -t- T
189 116 113 113 66 -g^-i-gg-, 106 TutllgS.
1 1 pnorsr^
10-20 20-30 30-40 >40
Depth
D Surface
T T DMid_Depth
T
29
j
55
80
T D Bottom
T . — i — |
ggj 19
994 40 68
177 129 404
0-18
18-27 27-32
Salinity
>32
Figure 3-6-26. Plankton Community Respiration (mmol Oi m~3 d"1).
72
-------
I./
1.2
Q. 0.7
0.2
-0.3
0212
T
37
i
82
n
rJ
r
JL
r
u
1
1
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T
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r
i.71
10
0509 0604 0606 0609 0704 0708
Cruise
1.6 -
1.2 -
Q-08-
m '
0.4 -
n n -
X
I
1C
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1
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I
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7 9
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1.6 -
1.2 -
m "
0.4 -
n n -
T
32
—
3
L
1
i
h
—
31
T
50
3-10
T -,- ,_
50
50
T
27
10-20
T
T . T .
26
18 T | ^
26 18 T8~| 40 -3Q-. 39
20-30 30-40 >40
Depth
1.6 -
1f\
.2. -
Q- 08-
GO
0.4 -
n n .
T
T
T
39 16
T
26
32
1
W
vv
WA
%
/SSI
T
10
D Surface
DMid_Depth
D Bottom
T
T
T
53 AA 23
\J\J A A ^
I |
0-18
18-27 27-32
Salinity
>32
Figure 3-6-27. Bacterioplankton Production (mmol C m"3 d"1).
73
-------
6 -I
5 -
4 -
S 3'
2 -
1 -
n -
6 -i
5 -
4 -
< 3-
m
2 -
1 -
n -
6 -i
5 -
4 -
< 3 -
m
2 -
1 -
n -
6 -i
5 -
4 -
< 3-
m
2 -
1 -
n .
te
0212 0303
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X M
T
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ri 19 ri 22 28
51N 24d 3°19 3
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to
0503 0509 0604 0606 0609 0704 0708
Cruise
ci -rjlif1! T
326 7 9 9
IT1! JC^JT f^lr1! H
"4^1|pl17 |^ 4105|ppp]
ABCDEFGHIJK
Transect
T -,-
57 57 57
10-20
T
I r
?
-_, 32 19
61
39 43 ^|
T
31 29
20-30
Dept
T
10
1
29 " 23 23 47 -46~|-*6-|
30-40 >40
h
D Surface
DMid_Depth
D Bottom
T T
47 159 108
0-18
18-27 27-32
Salinity
>32
Figure 3-6-28. Bacterioplankton Abundance (cells I/1 X 109).
74
-------
3-7. Vertically Binned Water Column Bin Plots - Ratios
This series of 7 vertically-binned histogram plots are identical in structure to the last series. Each
4-panel figure shows bin-averaged variables among the categories: 1) Cruise, 2) Transect, 3)
Depth bin, and 4) Salinity bin. Each category was further split into surface layer (open bars),
mid-depth (hatched bars), and bottom layer (solid grey bars) bin averages. The error bars are
standard errors and the labels indicate the number of observations comprising each bin. These
plots represent molar concentration ratios among key nutrient variables. The plots are annotated
with a horizontal line depicting nominal Redfield proportions defined as: 106C : 16N : 16Si : IP.
We also assumed C:Chl ratio of 50 representing an average.
75
-------
120 -
100 •
,* 80 -
CL 60 •
I
z 40 •
Q
20 •
P
f
T
0212
80 -i
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73
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0 80 -
D.
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5 40 -
20 -
n .
I
1-1
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5
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42 .
w , , A
<\
r T T >R -Cj xTl ™ T
859 E? sd 3e37H 175 52^51 ffi^| .fspftS jRzFn
I I II I ririii^i I I^H
CDEFGH I JK
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rJL,
'
T
94
i
T
ny _
61 -T2TI '" ~£9~TT|-| 126 153 111
I I I
10-20 20-30 30-40 >40
Depth
1=1 Surf ace
I I Mid_Depth
T I I Rnttnm
T
80
T
T_
t
_
-
h
1
79
_ . _. - .
T
I
T
1S
19 , 1-^^-1 -
1 1 1 1
0-18
18-27 27-32
Salinity
>32
Figure 3-7-1. Dissolved Inorganic Nitrogen: Phosphorus Ratio.
76
-------
D.
Q
120 -,
100 -
80 -
60 -
40 -
20 -
n -
A_i JL
23
^
44
19
30
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4d
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24
28
^
22
48
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60
43
^^^^
ff
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
uu -
80 -
60 -
40 -
20 -
n .
1924
JL
JL
2L I
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n
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24
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80 -
fin .
D.
Q
1 40 -
Z
P 20-
n -
T
T
64
ryfy
19
^jr T
62
3-10
80 -i
60 -
Q
K 40 -
z'
H 20 -
n .
156
'//>
76
149
10-20
76
61
/tD
20-30
Depth
T
46
47
T
-1— I 90
137 n-
46 8/
30-40 >40
03^1 Surface
HZIZlMid
Deoth T T
i i Bottom
rJoHfiolH
T
76
3£
!
62
66
25
T
15
T
T
171
58
T T
50
119 21 P ,00
iia 293
0-18
18-27 27-32
Salinity
>32
Figure 3-7-2. Total Dissolved NitrogenrPhosphorus Ratio.
77
-------
40 -i
30 -
-^
Q 20-
l
w 10 -
T
19
1
?4
T
1
58
0212 0303
40 -i
30 -
I 20 -
" 10-
H
I
"
20 -i
15 -
Q 10 -
I
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5-
0 \
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2ite
X
T
71
1
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3IL - & 86S^ fin
38H r^4A 5 13M pp* M M204, 69W 2*q pg^ fe3U
0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
341431
M
Cruise
T I I
IT T |*|
["I t-rl T 1^1 -r- 4? LJ-r 1 Kd -r ^.^r, r~p/lF)l| ^ 5 I M w"1") n
r T4^ P rr^l r T°n "1 \ H^^ PI P^ rTiTn rTT ! \\ r3!
1 33 "
ABCDEFGHIJK
Transect
I rJL,
1
J_ , JL. , ^ T
15
|
67
3-10
20 -i
Q 10 -
I
CO
5 -
n - -
81
T
32
0-18
121 T I-1— | 123
ISO ' -|-|4 D' y^ 1t)2
1 1 1
10-20 20-30 30-40 >40
Depth
1 ISnrfarp
1 IMIH_nppth
1 1 Rnttnm
1
T
T
JL — L- , T
T /; 1 206 on< 1 '
I
\
77 18 13 . D' ""' 256 422
j3 II 1-J b/
18-27 27-32 >32
Salinity
Figure 3-7-3. Dissolved SilicarNitrogen Ratio.
78
-------
o
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
120 -i
100 -
80 -
XMABCDEFGHIJK
O
Q
o'
o
Q
120 -I
100 -
80 -
60 -
40 -
20 -
41
6
|
42
136
ff/
31
T
128 |T5~ 19 73 ~%T~TF 41 73 66 60
3-10
10-20
20-30
Depth
30-40
>40
O
Q
O
O
Q
120 -,
100 -
80 -
60 -
40 -
20 -
^
] Surf ace
I I Mid_Depth
' ' Bottom
HH-7^
63 27
- Redfield
T
51
45
JL
T
t>
g
T T |
RsT 14 40 H2T 98 244 I
0-18
18-27
27-32
>32
Salinity
Figure 3-7-4. Dissolved Organic Carbon:Nitrogen Ratio via Shimadzu.
79
-------
50 -i
40 -
z 30 -
D.
o' 20 -
Q_
10 -
0 -
A
T
29
18
18
r^, T T T
[73X1 -r.-^.^ .— i— T—. rH'Tn fp4Tl rLHf=i JH —jir31! r^tpil r~l7n
p 1 | 274529 p3^B44] |4f Tl H T 1 rTTI FTfl H^TH TTH 1 H H
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
30 -i
25 -
20 -
z
Q- 15 -
I
g 10-
5 -
n -
1
321633
y 1 a
x 35 1= 32 r-p ^j.1] r31 .-1=1-, H"!1! .-f3"! i* PI -rVi r^12^
R14 ^3+° J61J2937 54 51J30 » ^| ^ ^15^ ^7^ ^^ ^ ^j ^
XMABCDEFGHIJK
Transect
20 -i
15 -
o' 10'
°~ 5 -
n -
TJU
T JL _L_ |
70
T -r
-JL- -r . - J^^^-| — •— ~^~ 122 112
.- 44 'D i40
Depth
20 -i
15 -
Q-, 10 -
* 5-
n - •
C^l Surface
i i Mid_Depth
T ' ' Bottom
1 T nnHfiniH T
T
85
,-HH r^ ^^
- r^~ T — —
2a 6° — ™ — 108 I
79 15 22 41 67 207 '"" 419
0-18 18-27 27-32 >32
Salinity
Figure 3-7-5. Particulate CarbonrNitrogen Ratio
80
-------
250 -i
200 -
a. 150 -
Q_
o' 100 -
D.
50 -
n .
T
15
1
25
17
JL
47
JL
33
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25
^•1
45
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29
-X
42
J,
27
44
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46
19
,1,
42
T
49
22
50
I
46
18
^
45
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78
T -X.
33
^
73
"*"
84
25
^
84
-t
88
I
83
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81
I ,,
4
74
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704 0708
Cruise
200 -
0.
I ..™
o 100 -
D.
50 -
n -
32
200 -i
150 -
D.
D-| 100-
o
°~ 50 -
n -
15
X
3L
34
ffl
M
T
T
69
200 -i
150 -
Q_
Q-, 100 -
o
Q_
50 -
n ..
^
12
3-10
r
83
J
51
k
54U
A
69
j
31 2
„
5
c
56
29
c
B C
T
198
28
__=__
60
•—
ij
«
52
\1
D
-r
64
190
10-20
T
79
=,
51
!2
^
32
3f
56
E
Transect
T
123
44
28
=,
56
37
F
n
T
117
20-30
Depth
14
32
G
r
72
5£
2C
H
T
43
=1
53
34
-
76
X,---
6
33
.4
X.
13
43
22
1 J
.— X_ T
30-40
C=
DSurl
ace
I IMIH Depth
1 1 Rnttnm
T
15
T
22
218
T
40
-p
iedfield
65
124
125
I,
2 19
K
122
>40
T
206
%
205
427
0-18
18-27 27-32
Salinity
>32
Figure 3-7-6. Particulate CarbonrPhosphorus Ratio.
81
-------
60 -,
50 -
40 -
D.
Q-! 30 -
iE 20 -
10 -
0 -
T
JL T IT X.
r1 X, JL
pffi Fft FR28 Effl 46 IS42 4922^i 4eiB^i
xl
E
T JL
!324 X
51 ^22
0212 0303 0306 0311 0404 0503 0509 0604 0606 0609 0704
Cruise
60 -
40 -
D.
Q_
I
iE 20 -
0 -
I XT |Y [V JL
^JL i^il. - - T T T I, -"TX. T
Sr x. _ n =, ^l j5 X jK14
_ T T 1—1 I "^ I ~>r T^ 54
5^ 3^fe 3U6M 955 54 ^ 3857 34^ 55 2C
I \ I I I
XMABCDEFGH
Transect
80 -
60 -
D.
°-. 40 -
i
~z.
?o -
n
T
T
T T ^^^ T | = 1 _I L
69 12 68 iy/f 62 189 " 42 117 7* 42
3-10 10-20 20-30 30-40
Depth
40 -, i i Surface
Q_
i ^-
0.
n .
1 IMIH_nepth
1 1 bottom
T KeaTieio T
1 r^—i
-^-1 -
r^ 2- - 7Q ^T^I 215
83 60 15 22 40 64
ft X
X
52
34 ^ u
T,J z
1 1
J
?r Tre"r
0708
JL
43
T
t
22 J
19
K
T
16
x
108
>40
T
T
2nn
191
^
411
0-18
18-27 27-32
Salinity
>32
Figure 3-7-7. Particulate NitrogenrPhosphorus Ratio.
82
-------
3-8. Scatter Plots of CTD and in situ Variables
The following 2 figures show scatter plots relating CTD variables to their comparable in situ
measurements for each cruise. The first figure shows relationship between CTD in-vivo
fluorescence (IVF) and extracted chlorophyll a (ug L-l) for each cruise. The second shows
relationships between CTD optical backscatter (OBS) or beam attenuation (ATTEN) and total
suspended solids (TSS, mg L-l) for each cruise. In both cases, the regression lines were fit
through the origin, such that the slope of the relationships can be used to scale CTD data into
estimated chlorophyll and TSS, respectively. For chlorophyll, the 2007 cruises included
additional data collected with a SBE25 CTD system (pink symbols).
83
-------
Figure 3-8-1. CTD in-vivo fluorescence vs. extracted chlorophyll a for each cruise.
84
-------
15 •
35
GM0306
OBS
20
30
Figure 3-8-2. CTD Optical Backscatter (OBS) or Beam Attenuation vs Total Suspended
Solids (TSS) for each cruise.
85
-------
3-9. Surface Water Quality Along Cruise Tracks
The following 10 figures depict surface water quality as measured underway during 10 cruises
from March, 2003 to August, 2007 to examine spatial patterns in physico-chemical and optical
properties. The surface mapper system was comprised of a YSI 6600EDS (Extended
Deployment System) multi-parameter datasonde coupled to a global positioning system (GPS),
included temperature, conductivity, pH, dissolved oxygen, chlorophyll fluorescence, and
turbidity. Water was pumped via a ship's hull pump through a de-bubbler before entering the
sample chamber. Date and time, and GPS position were recorded to a 650 MDS handheld
datalogger. Logging intervals varied between 30 seconds to 5 minutes depending on the cruise.
On each cruise, the surface mapper was run continuously ranging from 94 to 245 hours,
collecting between 1,062 to 23,915 data records.
86
-------
GM0303
94°W
fl?°w 91 °W 90°W 89°W 88°W
38
u 30
»
20
_~ 15
I 10
§ 5
40
- 30
5-20
€
^ 10
0
r-
40
30
20 -
/i
. '
_L
;
(L M
U. .. A^^
200
150
100
50
Q
4(3
30^
I
20
10 !
0
3.3
8.5
7.5
R<;
i I '
I
Not Measured
i i i
i
i
03/19 03/20 03/21 03/22 03/23 03/24 03/25 03/26 03/27 03/28
Figure 3-9-1. Surface Water Quality along Cruise Track, GM0303.
87
-------
GM0306
;:N
35
O 30
i»
20
15
30'
94°W
92°W 91 °W 90°W 89°W 88°W
30
_- 15
40
520
40
30
20
10
C
8.5
7.5
fi s
-
Not Measured
i i i
i
06/13 06/14 06/15 06/16 06/17 06/18 06/19 06/20 06/21
Figure 3-9-2. Surface Water Quality along Cruise Track, GM0306.
88
-------
GM0311
30"N
29DrsT
30'
30'
94°W
93°W 92°W 91
<5C°W
89°W 8S°W
o 30
Q>
•8 ->jt
| 20
t—
1 J,
9fi
_— 15
t_
f 10
8 5
dfi
5 30
^ 20
1,0
0
Q C
85
Q.
7.5
''MX^~^*~^~/^J*-— -~-^S^__Jj t^_^v-^rts~^-v/^>" v"x^j*'*"1 "'**s^ /•*^v^v*-i/~*^v.h ' ^x
-
. ;
, , V/ , i
< 1 < <
- 1
f^l 1 /
'liwiuAj^ ^ °v X
^^•^v<^^^/ siSSsr~-i-*^-*--^-s
i 1 i i i II
i i i i
i
,\
•
1 , . ^ A-
' .jV*^ H^Wi£jJ5'*'s^'-4»(ti!/''^r -TJ"**1 1 "V^ilin'L • _?1H «_^*W
! ! 1
.
Not Measured
-
i i i i i i i i i i i
7L
TO Q
w*
^Ttf\
150 —
^
100 «
50 Q
m
30 -
20 1
10 <
0
11/07 11/08 11/09 11/10 11/11 11/12 11/13 11/14 11/15 11/16 11/17
Figure 3-9-3. Surface Water Quality along Cruise Track, GM0311.
89
-------
CMOS 03
30°N
ao1
29DN'
30-
28DN'
3.'24
94°W
92°W 91°W 90°W 89°W SS°W
35
o 30
en
H-25
i3
^20
•S
|2 10
9.5
7.5 -
S.5
40
30
2O
10
c
£\i
lio
S 5
n
-
N
I
ot Measured
i
-
£tfj
100
50
n
0
40
3O _~
20 S
10 5
0
-
•
Not Measured
03/23 03/2* 03/25 03/26 03/27 03/29 03/29 03/30 03/31
Figure 3-9-4. Surface Water Quality along Cruise Track, GM0503.
90
-------
Givioana
30°N
set
28DN1
30
35
6" 30
i owe
9,129 V9'28
94°W 93°W 92°W
90°W 89°W 8S°W
40
30
2O
10
c
1
i
w
,-~ 15
8 5
n
_
i
Not Me<
i
asurec
1
_
150 --
100 |
o
50 C"
i-
40
5 30
E. 20
-e
H 10
1
.
i£
III
1
f.
40
30
20
10
0
9.H
flfi
7.5
fi *,
-^
-^V-^w^1-
* J^^^l™^*
*
g
I
1
i i
09/29 09/30 10/01 10A)2 10/03 10AM 10/05 10/06 10/07 10ffl8
Figure 3-9-5. Surface Water Quality along Cruise Track, GM0509.
91
-------
29°N'
30"
3C-
94°W 93°
GMOB04
92 °W 91
89°W
88°W
ja
0 30
| 20
1 "
on
8 5
p30
S. 20
€
O G.
a.s
Q.
7.5
A =
- v " "*- '.
.
I i i i i 1 •" i
I ! ll |
Not Measured
:
i 1 i i i i 1 i
!
Not Measured
i
; i
ii i i i i i 1
i
Not Measured
i i i i i i i i
HU
3° =
a,
20«
10 V
onn
150 g-
,00 |
50 Q
Afl
30 ^.
20 3.
10 °
04/13 04/14 04/14 04/15
04/15
04/16
04/16 04/17
Figure 3-9-6. Surface Water Quality along Cruise Track, GM0604.
92
-------
GM0606
-jc
0 30
I»
£> 20
' '"i
.r- 15
8 5
Af\
5^30
E. 20
£ 10
29°N '
JH
30"
^0"
94°W 93°W
1
- ^iv-^es
-
-
_
' -
•- •-
- •-••-^.-,.,
••*•.
-• - -- -, r-
i J i
^Hr
i
6.' 10
92
.-/
-*--^-
-?- • ' v*^ -^
'ifc>^^^ <•« ! *$f> : '
iftL^
s- «^ei\">>
^~> 6.8*— JX i \y
1 H" — 1 ^^ W{ H^s/e
•
°W 91 °W 90°W 89°W 88°W
i i i i ii i
-•^L ~~^~'r- ^~'j=r~ ' s-cVw
-~^S*~^ ^^s. "^ f •'"'•"— .v-vo^.""*^ ' '-A— ~w' — **— —
_,""' v -'
: [
r
:
Not Measured
, ; , , [
.
:
~
:
^
.
i i i [ ii t
yir\
30
20!
,0S
0"
150 -
100 |
50 Q
Aft
30 _—
20 3"
10 5
06/07 06«7 06/08 06/08 06/09 06/09 06/10 06/10 06/11 06/11
Figure 3-9-7. Surface Water Quality along Cruise Track, GM0606.
93
-------
GM06Q9
O 30
i
B 25
Q.
| 20
^>n
_— 15
8 5
i/i
l—
5 20
^ 10
Q K
8.5
cu
7.5
C T
1 !i 5~^r^ ~^m ^ -•)»
^ H h rV^^^" :
**J H~7 ^\ SJs^
I I I 1 J
u U-LX'
"9HO
28°fSr'
94°W 93°W 92°W 91 *W 90°W 89°W 8S°W
I I ! 1 | 1
;' : ill
i I i i i i t i
Not Measured
i \
:
: :
ii i tii
-
I
-
; ;
111)111 1 1
-v^__ „__ _ ^ _
I
1 1 III 1
"5.
20 §
10
•?nri
150 g
100 os
50 0
30 _^
20 |
10 5
09/07 09/07 09/08 09/03 09/09 09/09 09/10 09/10 09/11 09/11
Figure 3-9-8. Surface Water Quality along Cruise Track, GM0609.
94
-------
GrulfJ7fJ4
30'
94°W
92°W
90°W 89°W
88°W
O£J
0 30
fl>
2.25
,| 20
•c=;
,»
s
'~-_-
Vi r~
^~ ..-
\
Vi
S^-HH!
^^^ **
I
•—-"-"'• f^ '* • •' iu^1 -d
•> '' f ' ' ••,
'""^ -vv"i;™™^
1
1
t \
•
j . :
f&*& .•--•^r
_
— i
*+u
30
20
10
n
T^ 15
DO
J. 10
8 5
n
. ''-' * ~_-v , *.f
PVV rwsl'V
I
w^*"^-
^•'
; J"i
.— 1_-^— .VJ> v-,.
I
MV*\.«,
i
150
100
50
n
30 -
20 -
-
-
7
'
.L
Sfifc
:'>.^
••
. '^ ^ ^. A
|
: -
. : -
•
. :
'
-------
30°fM
29DN
28°N
GM0708
94°W
90°W 89°W 88~W
o 30
S 25
|20
•c 15
o
a 5
jin
S30
5. 20
€
•2 10
'-"• ^
8.5
Q.
7.5
A *.
~._L__J_ ^^^c^^.-— ^....^-J-^^.^^ ^~
' ': 'v,
V
i i 'i-1 '• I i i " i i i
•; i
??v : — r-*- "^j****^ ^^ ™ •*->/"'* -• y^\r
fr . . "~^f |* ^ V- A^i.
i i i
! i
_ —
•
t
: : -,•; : 'Mi isfc
V1 i . « 1 t . , • 1 i • ., . 1 _i»_ 1 ^ W-^xk ' 1 .• *• .'
.
*
ill 1 1 i 1 i
30
a.
20 a
150 ;-
100 s
„-
30 ,.—
20 1
10 0
0.
08/20 08/20 08/21 08/21 08/22 08/22 08/23 08/23 08/24
Figure 3-9-10. Surface Water Quality along Cruise Track, GM0708.
96
-------
3-10. Surface and Bottom Layer Currents.
The following set of maps depict the distribution of surface layer and bottom layer current speed
(cm s"1) and direction on a subset of six cruises. The arrows are centered on sampling stations
and point in the direction of water motion. The length of the lines reflects current speed relative
to legend entry.
97
-------
Surface Currents - GM0503
92°W
91 °W
90°W
89°W
Bottom Currents - GM0503
30DN
40'
20'-
29°N
40'~
20'
28°N^
20 cm s
94 W
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-1. Surface and Bottom Layer Currents, GM0503.
98
-------
Surface Currents - GM0509
92°W
91 °W
90°W
89°W
Bottom Currents - GM0509
40'
20'-
29°N
40'~
20'
28 N T-
94 W
20 cm s
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-2. Surface and Bottom Layer Currents, GM0509.
99
-------
Surface Currents - GM0606
30 N
40'~
29°N
40'~
20'
28°N
20 cm s
94°W
93°W
92°W
91 °W
90°W
30DN
40'
20'-
40'-
20'
Bottom Currents - GM0606
I I L
28°N
20 cm s
94 W
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-3. Surface and Bottom Layer Currents, GM0606.
100
-------
Surface Currents - GM0609
30 N
40'~
29°N
40'~
20'
28°N
20 cm s
94°W
93°W
92°W
91 °W
90°W
30DN
40'
20'-
40'-
20'
Bottom Currents - GM0609
28°N
20 cm s
94 W
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-4. Surface and Bottom Layer Currents, GM0609.
101
-------
Surface Currents - GM0704
I | |_
30 N
40'-
29°N
40'~
20'
28°N
20 cm s
94°W
93°W
92°W
91 °W
90°W
30DN
40'
20'-
40'-
20'
Bottom Currents - GM0704
28°N
20 cm s
94 W
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-5. Surface and Bottom Layer Currents, GM0704.
102
-------
Surface Currents - GM0708
30 N
40'~
29°N
40'~
20'
28°N
20 cm s
94°W
93°W
92°W
91 °W
90°W
30DN
40'
20'-
40'-
20'
Bottom Currents - GM0708
28°N
20 cm s
94 W
93°W
92°W
91 °W
90°W
89°W
Figure 3-10-6. Surface and Bottom Layer Currents, GM0708.
103
-------
3-11. Water Column Process Stations
The following set of identically-formatted figures depict water quality time series at each of 15
process stations occupied during the 2006-2007 cruises. Surface (open circles) and bottom (solid
circles) water time series were taken at each site. During 2006 we sampled an additional one or 2
mid-depths (gray triangles, gray diamonds). The figure template is a cruise (5 cruises, rows) by
site (3 stations per cruise, columns) plot matrix. Two stations (Z02 and Z03) were sampled
during all five cruises. At each station, repeated water column measurements were made at 3-6 h
intervals over a 30-40 hour period. Figures 3-11-1 through 3-11-8 show selected CTD data from
surface, mid-depth and bottom depth bins matched to the discrete water samples, which are a
subset of the data shown in Section 3-14. Figures 3-11-9 through 3-11-17 show particulate
constituents and key ratios. Figures 3-11-18 to 3-11-39 show dissolved inorganic and organic
constituents and key ratios. Figures 3-11-40 to 3-11-44 show plankton community respiration,
bactedoplankton abundance, bacterioplankton production, and key ratios. Ratio plots for both
particulate and dissolved constituents are annotated with a dashed horizontal line depicting
Redfield proportions: 106:16:16:1 C:N:Si:P. A nominal C:Chl ratio of 30 was assumed typical
of phytoplankton.
104
-------
s
(O
o
O
0)
o
(O
o
O
o
o
s
O
00
o
24 -,
23 -
22
21 -I
20
0
<0 30 -
§ 28
i 26-
0
31 -,
30 £
29 -,
28 -
0
Z01
20
20
20
Time (h)
40
40
40
Temperature (°C)
Z02 Z03
24 n
23 -
22-
21 -
20 --
0
30 -,
28 -<
26 -
i-r
0
32 -,
31 :
30 -
29 ,
28 -
0
20
o°oo
20
20
20
Time (h)
40
24 -,
23 -
22
21 -
20
0
30 -
28 -
26
20
40
oooo o °<>
40
20
40
0
32 -,
31 n
30 -
29
28
20
40
0
20
Time (h)
Figure 3-11-1. Temperature (°C).
105
40
40
40
26 n
22 -I
21
0
32 -,
31 -
30 -
29 -
28 -
0
Z04
20
40
20
Time (h)
40
-------
Z01
0708 GM0704 GM0609 GM0606 GM0604
35 -
30 -
25 -
20 -
15 -
m
C
25 -
20 -
15 -
(
35 -
25 -
20 -
15 -
10
A A A A
OT^O^
) 20 4
•-MAAAA AM A
A A o*
A A Ag A
CXXXXXJi AA
D 20 4
?**•*£! 3?*?i
^oooooo^ooooo
0 20 4
Time (h)
-o- Surface
A Midi
0 Mid2
-•- Bottom
O
28 -
36 -W
32
0
36
32 n
28 -
24
0
28 -
24
Z02
20
20
20
20
Salinity
40
40
40
40
ooo-ooooooo— o
0
20
40
Z03
32 -
28 -
24
0
40 -,
36 -|
32 -
28 -
24 -
8=oS=ft=8=8=8=a
20
40
o
20
40
40 -,
36 -
32 -
28 -
J?t"^m?«
20
40
32 -
28 -
24
0
20
40
36 -
^••^
32 H
28 -
24
0
Time (h)
Figure 3-11-2. Salinity.
20
Time (h)
40
Z04
»••*••••••
28 -
o
36 -
28 -
20
40
20
Time (h)
40
106
-------
Z01
Sigma T
Z02
Z03
Z04
•*
o
(0
O
s
O
(0
O
(0
O
S
O
o
(0
O
S
O
o
r«-
o
S
O
00
o
!•«•
O
S
O
25
20
15
20
40
25 !
20
15 -
10
5
.
A A o A
DH30000I AA
25 -T,
20
10
5
20
40
20
Time (h)
40
26
24
22
20
18
16
14
26
24
26
|4
20
18
16
14
26
24
22
20
18
16
14
20
40
20
40
20
40
»••••••••••••
20
40
»»• ••••••••
DOO—OOOooOO—O
20
40
26
24
22
20
18
16
14
26
24
22
20
18
16
14
26 -i
24
22
16
14
26
24
22
20
18
16
14
26 -i
24
22
20 4
18
16
14
^••^ ••••+99^
20
20
20
20
40
40
40
40
20
40
26 n
24
22 H
20
18
16
14
»•••••••••
20
40
26 n
22
20
18
14
20
40
Time (h) Time (h)
Figure 3-11-3. Sigma T.
Time (h)
107
-------
(O
o
(O
o
o
(O
o
o
•*
o
I*-
o
s
O
00
o
I*-
o
s
O
Z01
15 -,
CK)—O
A A
0
- " .
h^
0
10 -,
8 -,
2 -f
0
20
20
20
Time (h)
40
40
40
Dissolved Oxygen (mg L-1)
Z02 Z03
6 -
4 -
2 I
0
20
40
0-QOQOQ^CKXO-O
8 -,
6 -
4
2 I
0 -P
0
10 n
5
0
20
40
oo
6 -
4 -
2 -I-
0
0
20 40
OOo-H3<>OOOOo— O
20
Time (h)
40
0
8 -,
6 -
4 -
2 -
0 --
20
40
0
20
40
8 -,
6 -
4
2
0
OQOOQQ—OOOOQ
^ *
0
8 n
6
4
2 +
0
0
8 -,
6 -
4 -
2 4.
0
20
40
20
40
OOO^OOoOOOO— O
0
20
Time (h)
40
10 n
5
0
0
8 n
6
4 -
2 4
0
Z04
20
20
Time (h)
40
40
Figure 3-11-4. Dissolved oxygen (mg I/1). The horizontal depicts a nominal hypoxia threshold of 2 mg I/1.
108
-------
Z01
Dissolved Oxygen (mmol m-3)
Z02 Z03
(O
o
O
o
o
O
00
o
I*-
o
O
20
40
300 n
200
100 H
o
0
200 -
100 -
0
0
Z04
20
20
40
40
Time (h) Time (h) Time (h)
Figure 3-11-5. Dissolved oxygen (mmol nr3). The horizontal depicts a nominal hypoxia threshold of 63 mmol nr3.
109
-------
o
(O
o
s
O
(O
o
(O
o
^
O
0)
o
(O
o
s
O
^-
o
I*-
o
s
O
00
o
I*-
o
^
O
Z01
Dissolved Oxygen (% saturation)
Z02 Z03
150 n
0
20
40
0
20
40
150 -,
100 -;
50 -
0
0
150 n
100
50 H
0
0
Z04
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-6. Dissolved oxygen expressed as percent saturation. The horizontal line depicts 100% saturation.
110
-------
Z01
50 -,
(O
o
O
(O
o
o>
o
(O
o
o
o
o
00
o
o
o
Chi. Fluorescence
Z02
20
40
0
Z03
20
40
Time (h) Time (h)
Figure 3-11-7. Chlorophyll fluorescence (volts).
20 -,
o
0
15 -,
10 -
5
0
Z04
20 40
•
20 40
Time (h)
Ill
-------
Z01
Optical Backscatter (volts)
Z02 Z03
10 -,
20
40 0
20
Time (h) Time (h)
Figure 3-11-8. Optical backscatter (volts).
3 -,
2 -
40 0
4 -
2 -
0
40 0
Z04
20
20
Time (h)
40
40
112
-------
Z01
Chlorophyll-a (|jg L-1)
Z02 Z03
Figure 3-11-9. Chlorophyll a concentration (ug L"1).
Z04
40 -,
S 3°-
§ 20-
§ 10 -
0 0-
c
30
GM0606
->• K)
000
8 -,
S 4-
g 2
S o
o
0
6 -
,0-9 v % i ; ;
3 -,
3^ -/* 2
n
?^^^*^
\x^//\ A
20 40 0 20 40 0 20 40
n 40 -
*y£r ^P, 30 -
\ P 20 -
\* - A 2 ^ 10"
ft A _•— A — • A n
3 -
CX A 1 -
3 «
-W-W ^ •— ^"— =• 1 U -T" " ^ T ^ ~ 1 U "I 1 1
0 20 40 0 20 40 0 20 40
, 8-
^^^0 6
6 n
m /*^* » 4-
**N^^A
0 T^IA
20 40 0 20 40 0 20 40
3 n
Time (h) „
§ 1 '
o
O
0 -
-0- Surface 0
A Midi 6 -
GM0708
0 Mid2 4 _
-•- Bottom 9
0 -
Q _
^%
n
L 15 1
\ A • 10- /A^
V^*\/ \/ 5 -3O/*O\-/2\^-
20 40 0 20 40 0 20 40
6 -
"^^^ 4
f)
8 n
Jlh A ^ 6 ~ / \ ^
»- — »^^ ^-^"^\ M / \ •==A
^~-^-^"^ \ /^ /i ^7-^Q \ ^^7^ ^^\r~O
D 20 40 0 20 40 0 20 40
Time (h) Time (h) Time (h)
113
-------
Z01
Particulate Carbon (mg C L-1)
Z02 Z03
Figure 3-11-10. Particulate carbon (mg I/1).
Z04
2 -, 0
S 2 P\ Q 0
^j / ••^*^'^
0 -P m i ^ 1
0 20 40
3 1 3 1
g 20-0-o
U, <^/ \x
o 0 -P^O \, 0
0 20 40
1 -,
Time(h) Q
§ o-i
o
s n
U -0- Surface 0
A Midi 1
0 Mid2
00 ,.
° -•- Bottom 1
0
^ n
0 °
*^T§ 0 -
1 1 0
0 20 40 C
1 -
^.T^- «_^ °
1 1 0 -
20 40
1 ° 1
^A °-
¥&=:1f~^~~ 6— fe^ °
0 20 40 0
0 -
• 0 -
2^^3orv--^^L^o&^*=^ o -i
n
20 40 (
n 1 -
*^-^ /-""""^ ° "
n
0 20 40 C
Time (h)
I^^p^ A^ ^-O-. A A
ta/ ~~~~~~f^^ \\~~ — O
20 40
/°\
D 20 40
I I
20 40
2 -,
0 « 2 P
r^\|>O-^^/'3\7' -| _ iQ f^
^ •^o 1 i^pio^0— b^ ^^«*
n
) 20 40 0 20 40
1 -,
0 -
n
3 20 40 0 20 40
Time (h) Time (h)
114
-------
Z01
Participate Nitrogen (mg N L-1)
Z02 Z03
Z04
0.25 -,
Tt 0.20 -
g 0.15 -:
p 0.10 -
0 o.oo -1
0
0.60
<0
o 0.40
to
^ 0.20
O 0.00
0.60 -
0 00
/sj\ /XT"* °-40 -
^•L 0.20 -
D 0.15 -,
\ 0.10 -
\
\ 0.05 -
1 •=•—•-•—•— 8 n nn
0
^80^8^^8=0^
20 40 ° 20 40 0 20 40
-1 0.60 -,
•yO^O^O o 0.40
A C3 A 0.20 -
0.20
A ft~ — ^— _s _• — 8
o ~w ^^ n nn
n
0 20 40 0 20 40 0 20 40
0.20 -, 0.20 -, 0.15 -,
0.15
o 0.10
o 0.05
Q 0.00
0 A 0.15 -
o— o— o— ^8 0.10 -
A ^^^ n nc
* ° °-1°J
-> 0
0 20 40 0 20 40 0 20 40
0.10 -, « « 0.10 n 0.40 n
Time (h)
S O-05 -
o
0
0.00 -
-O- Surface C
»"Vi r^y^^^^"9 °'°5 "
n nn
9o o.so J? O
^\-^^ ^^c5 0.10 H^o ^^•^cy^^^
*^ n nn
) 20 40 0 20 40 0 20 40
A Midi 0.08 -^ 0.06 -, 0.08 -, » _^
CO
o
o
0 Mid2 0.06
-•-Bottom O-04
0.02
n nn
-
3\ 2 +/*J* °'04 "
, , n nn -
*P\\ P 0 • 0.06 - ^^^^^^^^•poT
i ^^^O^^SD 0.02 -
, , n nn
20
Time (h)
40
20
Time (h)
40
20
Time (h)
40
Figure 3-11-11. Particulate nitrogen (mg I/1).
115
-------
Z01
Participate Phosphorus (mg P L-1)
Z02 Z03
Z04
0.025 -, ~ 0.060 n 0.008 n
•* 0.020 -:
S 0.015
o 0.010
^ 0.005 |
" 0.000 -F
> A n /*
V/AX/^VA/ A 0.040
° J*~~~+ O-020 -
~^ T 0 000
A 0.006
0.004 ^
^^r^\^«-*7=« °-002
K=B^ O^* n nnn
:xA»"*^»^ j*
_
0 20 40 0 2° 40 0 20 40
0.040 -, 0.080 -, _ 0.040 -, ^
g 0.030
g 0.020
S 0.010
O n nnn
O 0.060
3r°^°~^^or 0.040
» ^-^ 0.020
r 0.030
/ 0.020
/ \
»;-£
o 0.010
to
o 0.005
S n nnn
^o-cx °-015
^ Or 2 0.010
^ •~~_^ A/^^^^ 0.005
* ^W ,-, rtrtrt
r o.ooe
^•i «^ /O 0.004
JQ^f^^^^ ^ 0.002 -
A n nnn
^^*o\ ^*
\<> /s ")* 9^^
>A A
A
~_ U.UUU \J.\J\J\J ~1 \J.\J\J\J ~1
0 20 40 0 20 40 0 20 40
0.015 -, 0.020 n 0 060 n
Time(h) 0.010
o
r- 0.005
o
S 0.000
•(--xA O-015 -
•6^^°"\w^*8 0.010 -
V^ " 0.005
n nnn
U.UUU
f\ 0.040 0
/ \ /
^O0-^»?>*»o ° °2° ^i®00**00^— *•
n nnn
i i U.UUU n 1 1
0 -0- Surface 0 20 40 0 20 40 0 20 40
A Mid1 0.015 n 0.010 ^^ 0.015 n
oo
o
o
0 Mid2 0 010 -
-^Bottom
U.UU3
g 0.000
/O f
\ / AN/ 0.005 H
Q-/ \ /O
A* ^
_ n nnn
/V 9 9\ m
o^:>+mo o.oos j:^
** f\f\f\
i \j.\j\j\j i i U.UUU ^ ^ 1
0 20 40 0 20 40 o 20 40
Time (h) Time (h) Time (h)
Figure 3-11-12. Particulate phosphorus (mg I/1).
116
-------
Z01
TSS (mg L-1)
Z02 Z03
Z04
1 -,
"* 1 -
o
o ° - /
O „ A
0
0
3 -,
jo _
O 2 3
to
o 1 _»
CD n
""*• y
0
1 -,
0 1
to
o
^ n
0 °
0
o
o
^J
O
00
0
0
^>
O
2 -
• 2 -
^-
*\o./ 1 -
n
1 -,
/9 ^^
~/ \ /
m w/
/
^^^^^^^/
3-OO O
1 1 n I xx I I
20 40 0 20 40 0 20 40
6 n 4 -
- ° A
4
0 3
2
• 2- A ^
n n
*
~
I I U I I U i i
20 40 0 20 40 0 20 40
1 n
1 -
n
i U H
1 n
1 -
n
\ 1 u ~
I I
20 40 0 20 40 0 20 40
20 -
Time (h) 15 -
10 -
5 ->
n
U
-0- Surface (
A Midi 1 -
0 Mid2 1 -
-•- Bottom °
0 -
n
U
• 8-
/
^__Q, / 4 -
5%*S*^Z«^^r, 2
J O^^ ^^^» O r\
20 n
T?_ 15 _ ,Q
/ 1 P\ 10 "o » 9
//'{f* 1 ^Oo 5 " •>/
J^CT"^ " ~~^J *^~U ^ O
3 20 40 0 20 40 0 20 40
_ 1 -
\\_^ /°
Ol»
n
I U
4
CX, *\ 3 - m. m^— * •
^^"""-\^ \x 9 ~9^^
"o^V^ i o-o '^--
-------
<0
O
O
(0
O
(0
O
O
(0
O
O
o
o
O
00
o
o
O
Particulate Carbon:Nitrogen
Z01
Z02
Z03
20
15 H
15 n
10
5 1
0
20
40
20
40
20
40
20
40
20
40
10
5
0
10
Z04
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-14. Ratio of particulate carbon to nitrogen. Horizontal line depicts Redfield ratio of 6.6 for phytoplankton.
118
-------
Z01
Particulate Carbon:Phosphorus
Z02 Z03
Z04
250 -,
•* 200 - Q
§ 150 A>|
o 100 g^-?
§ 5S~
0 H
0
300 -,
2T
{£) 1K~~~~~
g 100 &/- -
O o
0
150 -,
o> 100 4ja?
o 5^*
S 50 ^ A
1 1
0 °
0
^-
o
r«-
o
g
CO
o
h.
o
s
._ 300 -i 800 n
I>^Q ,JJ
•*W^A--^^- • 100-
o
D, 600
|\^ r*JQ^ Q ~ 40°
^8-^fHk^8 200
A n
/
/
9 •• V ™ ™ ™ "
20 40 0 20 40 0 20 40
300 -, 400 -,
°^°x 200
]!rf^*^ - - 100
n
r-^— O— 0— O^° 30°
A ^nn
&
o
A A y\ ^ww
^^~« n
/°\
^/ ^i vK
^S^S<2^>«-
20 40 0 20 40 0 20 40
400 -, 400 n
O ^^ 200
100 ^
300
e, 20°
J^a*r=*=^=^*^A- 100
* n
A
o _/-\ *
£jtaV2r^^_«^a _
i*~ ^i-^^^fl^CT ^*
20 40 0 20 40 0 20 40
600 -, 300 n 200 -,
Ttme(h) 400
200
^ 200
\
\^ 100 -
f 150 ,| »«0— JJ3TT**
**\^ C^O — o ^O /-\ 1 0 0 ~ **-^g ^^^^^ ^^ \~ ~ /*• O ~
" ^/^J*0^*" "50 o
9 n
-0- Surface 0 20 40 0 20 40 0 20 40
A Midi 600 -, 400 -, 300 -,
* Mid2 400 _
-^Bottom
0
n 300
B^QfcffSg".. ^0
0
/Q _ ^^^ 200 - _m^ ^ ^
2 //w*^y\*x^ '^OHm-^^^ — ~o*^:
1 1 n
20
40
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-15. Ratio of particulate carbon to phosphorus. Horizontal line depicts Redfield ratio of 106 for phytoplankton.
119
-------
Z01
Particulate Nitrogen:Phosphorus
Z02 Z03
Z04
40 1 Q
S 3°- f\4
o 20 :W-*
o
w 0
0
60 -,
(0
o 40 :Xrv
100 -f
0 I
i 50 V-fr
0 o
O
O
O
CO
o
r-
o
300
i O^O^ 200
£NQ_\:_V^_ 100
1^^»
20 40
60 1
^-Q J* 40 C
- 1-r t~ ^g
20 40 0
/ 40 -
jg/__0 20
• ^^ • • • • •
20 40 C
100
Time (h)
50
-O- Surf ace (
A Midi 30 -
* Mid2 20 H
"•-Bottom
0
-^, 100
- \ 50 -
» -a- • - •• e ^- • n
0 20 40
100
^^•^CT ^^O 50
^ir^^a n
20 40
80 -r
A o 60
A o /'"\ 40 •
8^^^K^X^-4«Jj - 20 j
) 20 40 0
i 60 -,
A 40 -
J 20 40 0
0 30 n
*S^_ _ -^*\^+.- . 20 "
0
^^^/
0 20 40
i* ^^g^f^f .
0 20 40
)
^\ o^Q
rft^^t^fi— *^«- -
^
20 40
o 60 "k
y\,^? 2o~]frv^^^^
20 40 0 20 40
20 -, ,.
»cx— •*^a^r/* " 10 $r^
J <• 5 -
1 1 n
20
40
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-16. Ratio of particulate nitrogen to phosphorus. The horizontal line depicts Redfield ratio of 16 for phytoplankton.
120
-------
o
o
(0
O
o
!•«•
O
O
Z01
Particulate Carbon: Chlorophyll a
Z02 Z03
30°
Z04
20
40
20
Time (h) Time (h) Time (h)
Figure 3-11-17. Ratio of particulate carbon to chlorophyll a. Horizontal line depicts ratio of 30 for phytoplankton.
40
121
-------
Z01
•*
o
<0
O
s
O
(0
O
(0
O
S
O
o
(0
O
S
O
o
r«-
o
S
O
00
o
!•«•
O
S
O
6
4
2 JA A
3
2
1
0
2 -,
1
1
0
20
20
20
Time(h)
6
4
2 H"
_^ 0
40 °
15
10
5
—, 0
40 0
40 0
6
4
2 H
0
0
8
6
4
2 H
0
NH4(MmolN
Z02
20
20
20
20
40
40
40
20
40
3 -,
2 -
4
3
2
0
3 -i
2
40 0
6
' 4*
2 H
^ 0
Z03
20
20
20
20
20
Time (h) Time (h)
Figure 3-11-18. Ammonium (NH4+, umol L"1).
40
40
40
40
*n
40
6
4
2
5
0
Z04
20
20
Time (h)
40
40
122
-------
NO2
N L-1)
Z01
Z02
Z03
20
40
20
Time (h) Time (h)
Figure 3-11-19. Nitrite (NO2% umol I/1).
40
Z04
20
40
123
-------
o
(O
O
(O
o
(O
o>
o
o
o
o
00
o
N.
o
o
50.0 -,
8.0 -,
6.0 -
4.0 -
2.0 -
0
Z01
NO3(nmol N L-1)
Z02 Z03
1.0 -,
0.5 -
0.0
20
40
0
20
20
Time (h)
40
4.0 -,
3.0 -
2.0
0
15.0 -,
10.0 -
5.0 -
0.0
0*
20
0000
°°
0
8.0 -|
6.0
4.0 -
2.0 -
0.0 -
20
0
20
40
s
S
40
40
40
0
0
4.0 -,
3.0 -
0.0 -i
0
2.0 -,
1.5 -_
0.5 -
0.0 +
0
0.8 n
0.2 -
0.0
0
20
20
20
20
20
40
40
40
n
40
40
8.0 -,
6.0 -
Z04
Time (h) Time (h)
Figure 3-11-20. Dissolved nitrite plus nitrate (NOx, jtiniol L-l).
40
124
-------
Z01
DIN (jjmol N L-1)
Z02 Z03
50 -i
10
s
(O
o
(O
0)
o
o
o
00
o
o
o
8 -,
6 -
2-
**i^
0 20
Time (h)
40 0
20 -,
15 -
10 -
5
0
20
40 0
4
3 -
t>OO 2
0
0
10 n
20
/ ¥
20
40 0
8 -,
> 6 -
4-*
) 2
—, 0 —
40 0
20
20
20
Z04
40
10 -,
5 -
-^ 0
40 0
8 n
40 0
20
oo
40
Time (h) Time (h)
Figure 3-11-21. Dissolved inorganic nitrogen (NH4 + NOx, umol L"1).
20
Time (h)
40
125
-------
o
s
O
(O
o
(O
o
o
o
^
o
o
o
O
00
o
o
O
Z01
1.0 -,
0.6 -
0.4 p
0.2 -
0.0
)&-6-
0
1.0 n
0.5
0.0
20
20
20
Time(h)
0.8 -,
0.4 -
0.2
—, °-°
40 0
3.0 n
40
PO4(|jmol PL-1)
Z02 Z03
0.6 -,
0.4 - ?\
/ \
S^^ 0.0
20
40
—, 0.0 ^3H«4oO—CKXXXXD
40 0 20 40
2.0 n
k 1.5 -
1.0 -
0.5 -
0.0
0
20
40
0.4
0.3
0.2
0.1 -
0.0
0
4.0 -,
3.0 -
2.0 -
1.0 -
0.0 -
20
40
0
20
Time (h)
0
0.3 -,
0.2 -
0.1 -;
o.o -
20
40
0
20
40
0.3 ->
0.2 -
0.1 J
0.0
0
0.3 -,
0.2 -
0.0
20
40
•••"Stf**9*
0
1.0 n
20
40
«
0.0
40 0
20
Time (h)
40
0.4 -,
0.3 -
0.1
0.0
0
0.6 n
0.0
Figure 3-11-22. Dissolved inorganic phosphate (DIP, umol L"1).
Z04
20
40
20
Time (h)
40
126
-------
o
Z01
Silica (pmol Si L-1)
Z02 Z03
20
20
Time (h) Time (h)
Figure 3-11-23. Dissolved silica (Si, umol I/1).
40
0 4-
0
15 -,
10 -
Z04
20
20
Time (h)
40
40
127
-------
Z01
•*
o
<0
O
O
(0
O
(0
O
S
O
o
O
o
!•«•
O
S
O
00
o
!•«•
O
S
O
Dissolved Inorganic Nitrogen:Phosphorus
Z02 Z03
100
Z04
Time (h) Time (h)
Figure 3-11-24. DINrDIP Ratio. Horizontal line depicts Redfield ratio of 16.
128
-------
(0
O
O
(0
O
(0
O
O
o
o
O
oo
o
o
O
6.0
4.0
2.0
0.0
C
2.0
lio-t
0.5
0.0
3*M
0
1.5 -,
1-0-
Z01
20
20
20
40
40
Dissolved Inorganic Nitrogen:Silica
8.0
6.0
0.0
0.5
0.0
0
1.5
1.0 -f
0.0
40 0
30.0
20.0 -f
10.0
0.0
1.5
0.5
0.0
Z02
20
20
20
M*u
20
20
Time (h)
40
40
40
y
o.o
40 0
1.5 -,
1.0 ]•
0.5
—, 0.0
40 0
3.0
1.0 -p -1
0.0
0
1.5
1.0 4-
0.5
0.0
Z03
20
20
20
Q
20
20
Time (h)
40
40
40
40
40
Figure 3-11-25. DIN: Si Ratio. Horizontal line depicts Redfield ratio of 1.
Z04
40
129
-------
^-
o
to
1
o
o
to
O
CO
O
Z01
2400
2300
2200 H1
2100
2000
1900
0
2500 -,
2300
2100 -}
1900
0
2300
2200
2100 -
2000
1900
20
20
20
Time (h)
40
40
2700
2500
1900
C
2500
2300
2100
1900
40 0
2200
2000
1900
2500
2300
2100
1900
DIG (ijmol C L-1)
Z02
20
06
20
20
a
20
Time (h)
40
40
40
2200 n
2000
1900
I
2500
2300
2100
1900
40 0
2500
2300
6 2100
1900
2200
2100
2000
1900
0
2300
2200
2100
2000 -J
Z03
Ok
20
20
20
20
O
20
Time (h)
40
40
40
40
40
Figure 3-11-26. Dissolved inorganic carbon (DIC, umol L"1).
2200
2100
2000
1900
2100
2050
1950
1900
Z04
20
40
0 20
Time (h)
40
130
-------
•*
o
(O
o
O
(O
o
(O
o>
o
(O
o
^
o
o
o
O
00
o
o
O
Z01
Dissolved Organic Carbon (jjmol C L-1)
Z02 Z03
20
40
20
40
Time (h) Time (h)
Figure 3-11-27. Dissolved organic carbon (DOC, umol I/1).
300 -,
200 -
100 -
0 -
0
300 n
100 -]
0
0
Z04
20
40
20
Time (h)
40
131
-------
Z01
60 -
(O
o
(O
o
0)
o
o
o
o
O
00
o
o
O
Total Dissolved Nitrogen (pmol N L-1)
Z02
20
40 0
20
15 -
10
5 -i
0
40 0
10 -
' V
5 -
0 —
40 0
Z04
20
20
Time (h) Time (h) Time (h)
Figure 3-11-28. Total dissolved nitrogen (TDNs, umol I/1), measured on Shimadzu DOC/TN analyzer.
40
40
132
-------
•*
o
O
o>
(0
O
O
o
o
O
00
o
o
O
20
15
10
0
C
20
15
Z01
20
20
Dissolved Organic Nitrogen (pmol N L-1)
Z02 Z03
20
15
10
5
0
10
40
20
40 0
15
5
—, 0
20
40
20
40
20
40
Z04
20
Time (h) Time (h) Time (h)
Figure 3-11-29. Dissolved organic nitrogen via Shimadzu (DONs, umol I/1) calculated as TDNs-DIN.
40
133
-------
s
(O
o
s
O
<0
O
(O
o
0>
o
(O
o
o
•*•
o
r«-
o
S
O
00
o
r«-
o
S
O
0.6
0.4
0.2
0.0
C
1.0
0.5
0.0
0
1.5 n
1.0
0.5 •£
0.0
Z01
20
20
20
Time
Organic fraction of total dissolved nitrogen
Z02 Z03
40
1.0
0.0
40 °
1.0
0.5
-^ 0.0
40 0
1.5
1.0
0.5
0.0
1.5 n
1.0
0.5 -f
0.0
1.5
0.5
0.0
20
20
20
20
20
40
40
1.0
0.5
0.0
I
1.5
40 0
1.5
1.0
0.5
—, 0.0
40 0
1.0
-^ 0.0
40 0
1.0
J 0.5
I
-^ 0.0
20
20
20
20
O
20
40
40
40
—i 0.0
40 0
—i 0.0
40 o
Time (h) Time (h)
Figure 3-11-30. Organic fraction of total dissolved nitrogen (DONs/TDNs).
Z04
20
40
20 40
Time (h)
134
-------
O
O
o
o
O
oo
o
o
O
30
10
0
Z01
20
20
Time(h)
Dissolved Organic Carbon:Nitrogen
Z02 Z03
40
20
30
20
10
0
40
20
40
-5UU
100
C
20 -,
15
10
5
n
\
\
rt-*ft-ft9^^— ^ ..M .*.«
) 20 40
**~^\ x*\ ^^
+— • mr o
20
40
60
40
20
0
I
20
15
10
5
0
40
30
20
10
0
40 0
60
40
20
0
0
0
60
40
20
20
20
20
20
40
40
40
00
40
40
60
80
60
20
0
Z04
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-31. DOCrDONs Ratio. Horizontal line depicts Redfield ratio of 6.6 for phytoplankton.
135
-------
s
(O
<0
O
(O
o
O
0>
o
(O
o
O
•*•
o
r«-
o
S
O
oo
o
r«-
o
S
O
Z01
60
40
t
0
80
60
40
20 ^
0
0
30 -,
20
10
0
20
20
20
Time (h)
40
40
Total Dissolved Nitrogen ([jmol N L-1)
Z02 Z03
30 n
20
10
_^ 0
40 °
30
20
20
20
20
20
20
20 -,
15
10
5
—, 0
40 0
30
10
—, 0
40
40
0
1 -,
1
40
20
20
20
20
40
40
40
40
Z04
20
20
40
40
Time (h) Time (h) Time (h)
Figure 3-11-32. Total dissolved nitrogen via wet chemistry (TDNw,umol I/1) during 2006 cruises.
136
-------
o
o>
o
(O
o
S
O
•*•
o
r«-
o
S
O
oo
o
r«-
o
S
O
1 -,
0
2 -,
1
1
0
Z01
20
20
Time (h)
Total Dissolved Phosphorus (umol P L-1)
Z02 Z03
1 -i
0
40
20
2 -,
1 ^QQfr6<^
o
40 0
1
20
20
20
40
40
40
40
1 -,
o
1 -,
1
20
20
20
20
20
40
40
40
40
40
Z04
20
20
40
40
Time (h) Time (h) Time (h)
Figure 3-11-33. Total dissolved phosphorus via wet chemistry (TDPw, umol L"1) during 2006 cruises.
137
-------
Dissolved Organic Nitrogen (pmol N L-1)
Z01
20 n A
0 15 /S~° ^
to -in fc( A H /*s
o IU 5«i \ /»\
0 n _ *^*^Q
0 H r-°
0 20
30 -,
CO
o 20 Q-/-\/-vGQo O^Q
g 10 ^^•A^— *••
c^ n r
0 20
30 -,
o> 20- A
O ^»» A A /-tO-r^ cv/VAl
§ 10 jgStf^f^gg^
S 0
0 °
0 20
Time (h)
o
o
^s
CD
-O- Surf ace
A Midi
0 Mid2
CO
g -•- Bottom
o
0
Z02 Z03 Z04
20 n 20
15 0 A » 15 -
. 10 *V/8\o^-^o 10
w 5 £_£< A •"^ — — — i 5
0 0
A^^R
;-r^*^\\__^_^^4l
/ \*
^^ 0
40 0 20 40 0 20 40
20 -, 20
15 ^_^X>A_g^A2OQ 15
10 "•^^AA ••••• 10
5 <>*^» 0^^^ 5
0 0
i \J n i i \J
40 0 20 40
15 ¥^ *_• 20
10 9^^ * /**f* 15
m *^ 10
« 5 ~* 5
On
~ i i U
-,
-^^^0 /^Q^°A
C^^AS^^ ^^A£
-^ ^^
0 20 40
**AA*A fi*A*A
^ W ^ ^ ™ 99 ^ ^^
' '
40 0 20 40 0 20 40
1 1 1 1
1 - 1 -
On
I U
0 20 40 0
1 1
1 - 1 -
n n
u n i i u
-i
1 -
n
i U H \ 1
20 40 0 20 40
1
1
f\
1 0 H 1 1
20
40
20
40
20
40
Time (h) Time (h) Time (h)
Figure 3-11-34. Dissolved organic nitrogen (DONw) via wet chemistry (TDNw - DIN, umol L-1).
138
-------
Z01
Dissolved Organic Phosphorus (umol P L-1)
Z02
Z03
20
40
20
40
Z04
0.5 -,
** 0.4 8
O n o / \
to O--3 / \
o 0.2 L
g 0.1 -J-*--
v^ n n J
0.0 -H
0
0.4 -,
S ° 3 -fcf<
jo 0.2 f *
o ^
s 0.1
C) nn
^•^ U .U
0
0.6 -,
m 0.4 H3(VA
o Aji
«o 0.2 -~^
o p
S no
o °-°
0
o
o
^^
0
CO
o
o
0
0.3 -,. 0.3 n_
0.2
^D — 6 — °~^8^8 0.1
0 0
r-T^-^1^7* 0.2 {V*^g/S=8=^*
A AO^CX^X ^ (,_., 1 \g/
° n n
20 40 0 20 40 0 20 40
0.4 -, ^ 0.6 -,
kSfi2\ O° ° 3
f*^m^ffg 0.2
o 0.1
0 0
|^W§° QS^"^ o.4
• o\ v a •/\
VA/^ °2
•r ac— n n
_A_m«AQY~>
ItAAQxIlofiUMZ
I I \J.\J \ ^ I '^ I V/.V/ I I
20 40 0 20 40 0 20 40
C. 0.6 -, 0.6 -,
o°2°\oQ^? 0.4
O IP^ A ^ /^iB
^•-^ O^[ 02-
w~~~~-^^^
On
-j^oO ^o o.4
IS'^^jfc'^V' /^~~~~~?\Br^" i
Jj A^w Q2
W n n
A
iO^OaS^*4»j|.Qj
RrJ^Jo o°o5
.U ~l ^ i i w.w n i i
20 40 0 20 40 0 20 40
1.0n 1.0n 1.0n
Time (h)
0.5
On
.u
-O- Surf ace C
0.5
On
0.5
f\ f\
-
-------
Z01
Organic fraction of total dissolved nitrogen
Z02
Z03
Z04
0.8 n 1.0
O n n ^ 00
0.0 H
0 20 40
1.0 -, 1.0n
*° 05 k AA ft^o 05 j
g C>
CD n n n n
0 20 40 0
1.5n 1.5
0 °'5 °'5
f n n n n
^ij U.U U.U
0 20 40
1.0 -,
Time (h)
S 0.5
!•«•
0
!S n n
13 -0- Surface 0
A Midi 1.0
0 Mid2
oo
g -•- Bottom °-5
o
S no
o °-°
• — ^ — • 05 _
00
0 20 40 C
1.5
j/Si^s OA^OQ 1 °
On
20 40
] 1'5 1
+^" 0 5
On
0 20 40 0
1.0
0.5
0 0
20 40 (
0.5
0 0
0 20 40 (
Time (h)
^T^^*^*^
20 40
^**^§*^*§w8£
0 20 40
td***4— 8$**4
20 40
1.0 -,
0.5
n n
D 20 40 0 20 40
1.0 -,
0.5
1 U.U H 1 1
D 20 40 o 20 40
Time (h) Time (h)
Figure 3-11-36. Organic fraction of total dissolved nitrogen (DONw/TDNw).
140
-------
Z01
Organic fraction of total dissolved phosphorus
Z02 Z03
Z04
1.0 -,
S 0.8 0^
S 0.6 - r
0 0.4 /
g 0.2 -fi*—
0.0 -H
0
1.0 -,
| 0.5 -»*
O no
0
0.6 -,
S °Q42 f*
o
O
0
o
o
O
00
0
0
O
0.8 -,
Q j-v _ 06
•Q^^/H — Q
^^Q 0.4
"• 9i^ Q 0
1-0 i
0 A 0 & Q
_•__&—— •"'^ ^/
*"f P^®./ 0.5-
n n
»x%7*~4-
A
20 40 0 20 40 0 20 40
1.5-, 1.0
0.5 -_/$,
O • o ^o ^m*.^
On W A ^ •^ AW^O p. p.
k *fiA8A=-t«QflQ
o
20 40 0 20 40 0 20 40
~Q°« 1-01
On
1.5 -,
•^^ n n
^gOgA^gg
t****^**^9^
20 40 0 20 40 0 20 40
1.0 -, 1.0-, 1.0-,
Time (h)
0.5 0.5
On n n
-O- Surf ace 0
0.5
f\ f\
20 40 0 20 40 0 20 40
A Midi 10 -| 1.0 n 1.0-,
0 Mid2
-*- Bottom °-5 -
0.0
C
0.5
On
0.5
) 20 40 0 20 40 o 20 40
Time (h) Time (h) Time (h)
Figure 3-11-37. Organic fraction of total dissolved phosphorus (DOPw/TDPw).
141
-------
Total Dissolved Nitrogen:Phosphorus
Z01
Z02
Z03
20
40
20
40
Z04
150 -,
o 100 A /
to \-/
i so- °
1 nVv.
0 -F
0
200 -,
g 150
g 100
SS 50 ^QC
«» o *«*
0
30 -,
o Sftxi
tO 1n ,>-t>~i
J"J I U
° °0
o
0
O
oo
0
!•».
o
0 80
^\ 60
A 2~^r^^g 4°
•-^ — *
20 40 c
p 10°
/ 50
t282r^*£4
20 40 (
40 -,
^^^°&®8* • 20
•\ r\
n
20 40 C
20 -,
10
5
n
-O- Surf ace 0
A Midi 20 -
* Mid2 15 -
-•-Bottom 10 ~
5
0
80 -,
OL A A 60
n
) 20 40 0
80
*C***^*«A«»* 20
J 20 40
60 -,
8i^QV??^. 4°
^p- ^p
) 20 40 0
20
__________ 15
10
5
n
20 40 (
20
••••••••••' 15
10
5
0
^^ yy /jff\
// \ (__J--___ ^. ^-^^^
J^g* "A" ^~~~ ~ "^
20 40
J^_k A o
J^?i*«^5^«*f
D 20 40
fcSsS$=$sSsS
20 40
i 20 -,
10
5
n
D 20 40 0 20 40
i 20 -,
15 -
10
5
1 , n
20
40
Time (h) Time (h) Time (h)
Figure 3-11-38. Ratio of total dissolved nitrogen to total dissolved phosphorus via wet chemistry (TDNw/TDPw). The
horizontal line depicts the Redfield ratio of 16.
142
-------
Z01
Dissolved organic carbon:nitrogen
Z02 Z03
20
40
20
40
Z04
150
1 50
"" 0
(
20 -,
g 15
§ 10
_E 5
O n
c
15 ->
g 10
CO ^
0 °
_E n
0 c
0
O
O
oo
o
0
0
80
X P !n
/»\ /
a /*^r\w A 20
K^v^Q— £ O • n
) 20 40
° «*^9* 1°
0
) 20 40 C
• ^ -.-.-------.-----1
5
) 20 40
8 -,
Time (h) g _•
4
2
-O- Surface 0
A Midi 8 -,
0 Mid2 6 -
-•-Bottom 4 -
2
n
1 • 40
-A ^^ J^L\_k//^ 20 -
™ 1 0 -
0 20 40
15
n
20 40
1 15
^^^_F ^t~~^ ^
0 20 40 (
8 -,
4
2
20 40 0
8 -,
4
2
n
A
D 20 40
-y*^ft°— -_ _Jr*
»^ / •*C~~~8^^A
• __^ _^B1 B^^ W • •• J«B •• I
^_T ^P^ %^
0 20 40
frft_i»4 _££?**
) 20 40
8 -,
6
4
2
20 40 0 20 40
8 -,
6-_ __ ___
4
2
H 1 1
20
40
Time (h) Time (h) Time (h)
Figure 3-11-39. Ratio of dissolved organic carbon to dissolved organic nitrogen (DOC/DONw). The horizontal line depicts the
Redfield ratio of 6.6 for phytoplankton.
143
-------
Z01
Plankton Respiration (mmol m-3 d-1)
Z02 Z03
Z04
50 -,
•* 40
§ 30
o 20
O 1° "3-0-=
0 -F
0
30 T-,
§ 20 \
£ \
i 10 " V
(D 0 '•-•-
0
30 -,
§ 2°
§ 10 »ft
0 o^
o
o
0
CO
o
o
0
20
O 15
/ \ 1°
o^«^eK*--b o
1 20 1
A 15
A 10 -
tt A ^ ^ _Q Ik r
n
A
20 40 0 20 40 0 20 40
60 -,
40
n '
20 40 0
A 30
A JO 20
^^:n^tt^^^ 1°
PSo
A / 10
A A /
W^^
20 40 0 20 40
i 15 n
• 10
3H*5O^_^**^° 5
n
i
D*^ ^^6
•vB^^t*^^ — ,^-P*^
5* V?*O=^^>^
A
20 40 0 20 40 0 20 40
20 -,
Time(h) 15 _
10 |
5
0
-O- Surf ace 0
A Midi 20
0 Mid2 15
-•-Bottom 10
5
0
10
^^Ck^
Mt°^O — °^ ^° ° 5
10 ^*^m^
5o ^m^^^^'
\\ //*Xm 5 "
rt
20 40 0 20 40 0 20 40
1 J» 15
»-*^* *^* 5 -
n
L 30 1
*X*/*X^ 2° " 9m
^\\ o 10 d»°»
•^i , „
0 20 40 0 20 40 o 20 40
Time (h) Time (h) Time (h)
Figure 3-11-40. Plankton community respiration (WR, mmol Oi m"3 d"1).
144
-------
Bacterioplankton Production (mmol C m-3 d-1)
Z01
Z02
Z03
Z04
1.0 -,
^ 0.8
S 0.6
0 0.4
C3 n'n
0.0
0
10.0 -,
** 2.0 ^j-'»O^O^^D
O p
.U u.U ~\ 1 1
0 20 40 0 20 40 o 20 40
Time (h) Time (h) Time (h)
Figure 3-11-41. Bacterioplankton production (mmol C m~3 d"1).
145
-------
Bacterioplankton Abundance (X 10A12 m-3)
Z01
Z02
Z03
Z04
1 -,
•* 1
O A
<0 1
o o
0 °
0
0
15 -,
-------
Cell-specific bacterioplankton production (fmol C m-3 d-1 cell-1)
Z01
Z02
Z03
Z04
1.0 -,
•* 0.8
S 0.6
o 0.4
O n'n
0.0 H
0
1.0 n
-------
Ratio of baterioplankton production to plankton respiration
Z01
Z02
Z03
Z04
1.00 -,
•* 0.80
g 0.60
o 0.40
o °-20
0.00 -
0
0.40 -,
g 0.30 -0
g 0.20 \
S 0.10 ^_
CD o oo
0
°-60 "L.
o> 0.40 -^
§ 0.20 -g/
O
0
o
o
O
oo
o
!•«•
O
1.00-, 1.00-,
0.50
0 00
0.50
n nn
20 40 0 20 40 0 20 40
0.30 -, 0.15 -,
0.20
~™*=^ ^O n on
»°* 0.10
~ n nn
•^^°
20 40 0 20 40 0 20 40
0.60
•- 0.40
^^\ /NA
\\ " /*7^ n in
Q*~— OW^ 0.20
-
-
1.50 -,
Al -i 00
^
.UU -i u.uu J
20 40 0 20 40 0 20 40
0.10 -,
Time (h)
0.05
0 00
J\ °'2°
__^^O ^wx^ °-10 ~
^^ 0.05 -
n nn
f 0.10 -,
* \ 0.05 - O^^^^"*^
n nn
-0- Surface 0 20 40 0 20 40 0 20 40
A Mid1 0.30 ^ m 2.00 -, 0.30 n
0 Mid2 020 -
-•-Bottom
0 00
^r^
-------
5-72. High Vertical Resolution Water Column Profiles
The following series of plots summarize data collected during high vertical resolution water
column profiles taken at process leg during 2006-2007. On 1-3 occasions during the 30-40 hour
station occupation, the water column structure was sampled at high vertical-resolution using a
SBE25 CTD system integrated with a submersible pump, such that water samples collected were
closely matched with CTD measurements. This system allowed sampling of very thin layers.
Water samples were collected at multiple depths (usually >10 depths) to look at fine scale water
column distribution of dissolved and particulate constituents (Chl-a, nutrients, PC, PN,
bacterioplankton abundance and production).
149
-------
GM0606 Z01
-1
Temp, °C Salinity DO, mg L
25 30 35 20 30 40 0 5 10 7
i10
01
0
15
20
0
Q.
-------
GM0606, Z02
Temp, °C
20 30 40 20
30
DO, mg L
40 0 10
-i
20 7
pH DIQrnM Chl-aFL NH^M NO^M,
8 92 2.5 30 50 100 0 5 10 0 2 4
UJ
Q
18
15
20
NO , jiM, DIN,
PC,
5 10 0 10 20 0 2 40 10 20
No
Data
No
Data
BA,109L"' BP,MgCL-V
0 10 20 0 10 20
- 06/15/200619:30 -^- 06/16/200615:09
Figure 3-12-2. High Vertical Resolution Profiles: GM0606, Z02.
151
-------
GM0606,Z03
Temp, °C
Salinity DO,mgL
-1
pH
DIC,mM
Chl-aFL
4,
.25
^ 10
a
I
a
15
20
30 30 35 40 0 5 10 7.5 8 8.5 2 2.2 2.4 0 5 10 0 2 40 1 2
0 2 4
;f
A
A
I
DIN, uM PO , uM Si, uM
4
0 5 10 0 1 20 10 20
PC,
No
Data
PN,
No
Data
BA,10yL"
0 2
06/13/200618:31 -^06/14/200615:15
Figure 3-12-3. High Vertical Resolution Profiles: GM0606 Z03.
BP,
0 0.2 0.4
152
-------
GM0609, Z01
0
Temp, °C Salinity DO,mgL"1
29 30 31 20 30 40 0 5 10
pH DICmM Chl-aFL
8.5 2 2.2 2.4 0 5 10 0
NH,uM
4 r
•£ 10
a
41
Q
15
20
NO , uM,
x r
10
DIN,
5 10 0
PO ,
0.5
N02, nM,
2024
Si, nM
0 2 4
PC,
No
Data
No
Data
BA,10V
0 2 4
09/17/200618:00 -*- 09/18/2006 07:01
Figure 3-12-4. High Vertical Resolution Profiles: GM0609 Z01.
BP,ngCL~'d~'
0 2 4
153
-------
GM0609, Z02
0
Temp,°C Salinity DO,mgL~' pH DIQrnM Chl-aFL
29 30 31 20 30 40 0 5 10 7.5 8 8.5 2 2.5 0 10 20 0 2
NH ,uM
4
£ 10
a
-------
GM0609, Z03
-1
Temp, °C Salinity DO,mgL
.28 30 32 30 35 40 0 5 10 7.5
DICmM Chl-aFL
8.5 2 2.2 2.4 0 5 10
0.5
0 2 4
a
c
Q
15
20
N0x, nM,
510
a
01
Q
15
20
T
DIN,
024 024
0 0.2 0.4 0 5 10
PC, jiM
No
Data
11
i
PN,
No
Data
,\
I
BA,109L"1 BP,ngCL~V
012012
09/13/200619:01 ^09/14/200614:20
Figure 3-12-6. High Vertical Resolution Profiles: GM0609 Z03.
155
-------
GM0704, Z02
0
Temp, °C Salinity DO,mgL
20 22 24 30 35 40 4 6
pH DIC,mM Chl-aFL
7.5 8 8.5 2 2.2 2.4 0 2 4024 0 0.5 1
NH4,
a
«
Q
10
15
20
N0
DIN,
0 5 10 0 5 10 0 0.2 0.4
Si, pM PC, n
0 5 10 0 0.5
PN, nM BAJflV BP,
1 0 0.2 0.4 0 1 20 0.5 1
£ 10
a.
15
20
04/25/2007 20:34 -»- 04/26/2007 08:45
Figure 3-12-7. HigBi|ierti2jXBeSMfi6ft9iaei81es: GM0704 Z02.
156
-------
GM0704, Z03
-1
0
5
I10
I
Q 15
20
25
0
5
1 10
£
I
20
25
Temp, °C Salinity DO,mgL
20 22 24 32 34 36 4 6 8
7.5
pH DIC,mM Chl-aFL
8 8.5 2 2.2 2.4 0 2 4
0 2 4 0 0.2 0.4
NO , uM,
x r
DIN, nM
2024
P04,nM Si, (iM PC, nM
0 1 20 5 10 0 0.2 0.4
•N,|iM BA,109L"1
0.05 0.1 0 0.5 1
BP, ngCId'
0 0.5 1
-04/29/200719:22 ^04/30/200708:15 • 04/30/200717:25
Figure 3-12-8. High Vertical Resolution Profiles: GM0704 Z03.
157
-------
GM0704, Z04
0
Temp, °C Salinity DO,mgL
22 24 26 25 30 35 0 5 10
pH DIC,mM Chl-aFL NhL^M NO.^M,
8.5 1.5 2 2.5 0 10 20 0 5 10 0 0.2 0.4
I 5
n
Q
10L
NO , uM,
x r
BAJflV1 BP, (jgCL'V
o
DIN, uM PO (, uM Si, uM PC, uM PN, uM
4
0 5 10 0 5 10 0 1 20 5 10 0 1 20 0.2 0.4 0 2 40 2 4
I5
4)
10L
-04/27/200717:15 -^-04/28/200708:00 ' 04/28/200718:15
Figure 3-12-9. High Vertical Resolution Profiles: GM0704 Z04.
158
-------
GM0708,Z02
-1
Temp, °C Salinity DO,mgL
.28 30 32 30 35 40 0 5 10 7.5
pH
DIQmM
Chl-aFL
10
m
Q
15
20 u
10
15
20
DIN, \M P04,
10 0 5 10 0 2
8 8.5 2 2.2 2.4 0 2 4024 024
4 0
Si, nM
20 40
PC, nM
0 0.2 0.4
PN, nM
0 0.05 0.1
BA,10V1 BP,
2 30 5
•08/27/200719:30 ^08/28/200708:20 08/28/200719:05
Figure 3-12-10. High Vertical Resolution Profiles: GM0708 Z02.
10
159
-------
0
5
10
15
20
25
GM0708, Z03
Temp, °C Salinity DO,mgL~
28 30 32 30 35 40 0 5 10 7.5
pH DIC,mM
8 8.5 2 2.2
Chl-a FL
2.4 0 2 40
NO , uM,
x r
4£>:
i
, |j,M NO , |uM,
2 4 0 0.5 1
DIN, uM P04,nM Si, uM PC, ^M PN, ^M BAJO
20 2 40 1 20 20 40 0 2 40 0.2 0.4 0 2 4
BP, ngCL"d"
0 2 4
-08/25/200720:40 ^—08/26/200708:13 -• 08/26/200718:55
Figure 3-12-11. High Vertical Resolution Profiles: GM0708 Z03.
160
-------
GM0708,Z04
0
Temp, °C Salinity DO,mgL
30 31 32 25 30 35 4 6
pH
8 8
DIC,mM
8.5 1.5 2
Chl-aFL NH4,p
2.5 0 5 10 0 10
20 0 0.2 0.4
•£ 5
Q.
10L
NO , uM,
x r
f 5
Q.
10
ffl
DIN,
0 0.2 0.4 0 10 20 0 0.2 0.4
( i
I
m
(!:A
( ti
C/
Si, (iM PC, n-M PN, uM BA,109L^ BP, ^gCL^d
10 20 0 1 2 0 0.2 0.4 0 2 4024
08/29/200718:30 -^08/30/200708:30 08/30/200718:30
Figure 3-12-12. High Vertical Resolution Profiles: GM0708 Z04.
161
-------
3-13. Sediment Characteristics
The following series of figures depicts the depth distribution in sediments of numerous solid
phase and pore water constituents collected on the process leg of the 2006-2007 cruises.
162
-------
GM0606
Depth (cm)
en o en
^^ ^^1
J
\/^™
< 1
I
/ \
V^
o>
o
to
o
o
!•«.
O
00
o
I"-
O
§
O
0 50 100
Percent (%)
0 50 100
Percent (%)
0 50 100 0 50 100 0 50 100
Percent (%) Percent (%) Percent (%)
Z01
Z02
Z03
Z04
Z05
Figure 3-13-1. Granulometry.
163
-------
? 5
O
S f 10
§ &
g 15
<*(
f
1*
®
. (S>
(B
f .
(t)
£
(^
. ®_ .
i»
I
f
T
(S)
(S) .
O
«> f 5
§ r°
^5 Q
cB 15
O) ~ 5
0 E 5
1 f 10
^^ jn
® «
15
t
i
a)
<3
I
\s
1
®
I
f
A
t •
I
®
1
**$
\3 '
AN
\
¥
/
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Figure 3-13-2. Wet Bulk Density.
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Figure 3-13-4. Porewater DIC.
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Figure 3-13-10. Porewater Sulfate..
172
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Figure 3-13-12. Porewater TDN.
174
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Figure 3-13-13. Solid Phase Organic and Total Nitrogen.
175
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Figure 3-13-14. Solid Phase Organic and Total Carbon.
176
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Figure 3-13-16. Porewater Reduced and Total Iron.
Z05
178
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en o en
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179
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Figure 3-13-18. Sediment Chlorophyll a.
180
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Z05
Figure 3-13-20. Total Reduced Sulfide.
182
-------
3-14. Water Column Physical Properties at Process Stations
The following are time-depth contour plots of CTD variables collected during the Process Leg of
5 cruises in 2006-2007. On each cruise, 3 stations were occupied for -30-36 hours during which
time CTD casts were frequently conducted (3-6 hour intervals). These plots show how the water
column structure changed over the course of station occupation in sets of 2 plots for each station.
The first plot shows Temperature, Salinity, and Sigma T. The second plot shows dissolved
oxygen, dissolved oxygen saturation, chlorophyll fluorescence, and optical backscatter. The faint
symbols show the data points in the interpolation
183
-------
GM0604Z01
Temperature ( C)
Salinity
15
15
Sigma T
12 15 18 21 24 27 30 33
Elapsed Time (hours)
10
Figure 3-14-1. Temperature, Salinity, and Sigma T: GM0604, Z01.
184
-------
GM0604Z01
Dissolved Oxygen (rng L )
Dissolved Oxygen Saturation (%)
15
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
15 18 21 24
Elapsed Time (hours)
27 30
33
Figure 3-14-2. DO, DO % saturation, Chi, and OBS: GM0604, Z01.
185
-------
GM0604 Z02
Temperature ( C)
26
Salinity
Sigma T
12 15 18 21 24
Elapsed Time (hours)
27 30 33 36
10
Figure 3-14-3. Temperature, Salinity, and Sigma T: GM0604, Z02.
186
-------
GM0604 Z02
0
5
g
£ 10
£2.
Oj
Q
15
Dissolved Oxygen (mg L"
0
5
£ 10
Q_
OJ
Q
15
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21 24
Elapsed Time (hours)
27 30 33 36
Figure 3-14-4. DO, DO % saturation, Chi, and OBS: GM0604, Z02.
187
-------
GM0604Z03
Temperature ( C)
Salinity
Sigma T
12 15 18 21 24 27 3D 33
Elapsed Time (hours)
36
10
Figure 3-14-5. Temperature, Salinity, and Sigma T: GM0604, Z03.
188
-------
GM0604 Z03
0
5
JlO
s.
ill Ar-
Q 15
20
Dissolved Oxygen (mg L )
20
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21 24
Elapsed Time (hours)
27 30 33
Figure 3-14-6. DO, DO % saturation, Chi, and OBS: GM0604, Z03.
189
-------
GM0606 Z01
.£,
£ 10
-------
GM0606 Z01
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 13 21
Elapsed Time (hours)
24
27 30
Figure 3-14-8. DO, DO % saturation, Chi, and OBS: GM0606, Z01.
191
-------
GM0606 Z02
15
Temperature ( C)
Salinity
Sigma T
12 15 18 21 24 27 30 33
Elapsed Time (hours)
10
Figure 3-14-9. Temperature, Salinity, and Sigma T: GM0606, Z02.
192
-------
GM0606 Z02
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21
Elapsed Time (hours)
24 27 30 33
Figure 3-14-10. DO, DO % saturation, Chi, and OBS: GM0606, Z02.
193
-------
GM0606 Z03
Temperature ( C)
10
15
20
.32
j 3D
J2B
126
\24
Salinity
Sigma T
12 15 18 21
Elapsed Time (hours)
24 27 30 33
15
10
Figure 3-14-11. Temperature, Salinity, and Sigma T: GM0606, Z03.
194
-------
GM0606Z03
0
5
10
15
20
Dissolved Oxygen (rng L" )
0
5
10
15
20
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21
Elapsed Time (hours)
24
27
30
33
Figure 3-14-12. DO, DO % saturation, Chi, and OBS: GM0606, Z03.
195
-------
GM0609Z01
Temperature ( C)
24
Salinity
Sigrna T
0 3 6 9 12 15 18 21
Elapsed Time (hours)
27 30
15
10
Figure 3-14-13. Temperature, Salinity, and Sigma T: GM0609, Z01.
196
-------
GM0609 Z01
0
5
g
f 10
OJ
Q
15
Dissolved Oxygen (mg L"
0
5
^
f 10
O3
Q
15
Dissolved Oxygen Saturation (%)
150
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18
Elapsed Time (hours)
27
Figure 3-14-14. DO, DO % saturation, Chi, and OBS: GM0609, Z01.
197
-------
GM0609 Z02
Temperature ( C)
124
Salinity
15
0 3
Sigma T
15 18 21
Elapsed Time (hours)
27 30 33
10
Figure 3-14-15. Temperature, Salinity, and Sigma T: GM0609, Z02.
198
-------
GM0609 Z02
Dissolved Oxygen (mg L"
0
5
_§,
f 10
w
Q
15
Dissolved Oxygen Saturation (%)
150
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21
Elapsed Time (hours)
24 27 30 33
Figure 3-14-16. DO, DO % saturation, Chi, and OBS: GM0609, Z02.
199
-------
GM0609 Z03
Temperature ( C)
10
15
20
,
,
24
Salinity
20
SigrnaT
12 15 18 21
Elapsed Time (hours)
24 27 30
15
10
Figure 3-14-17. Temperature, Salinity, and Sigma T: GM0609, Z03.
200
-------
GM0609Z03
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 16 21
Elapsed Time (hours)
24 27 30
Figure 3-14-18. DO, DO % saturation, Chi, and OBS: GM0609, Z03.
201
-------
GM0704Z02
Temperature ( C)
Salinity
Sigma T
12 15 18 21 24 27 3D 33
Elapsed Time (hours)
Figure 3-14-19. Temperature, Salinity, and Sigma T: GM0704, Z02.
202
-------
GM0704Z02
0
5
10
15
Dissolved Oxygen (mg L
0
5
g
£ 10
Q_
OJ
Q
15
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21 24
Elapsed Time (hours)
27 30 33
Figure 3-14-20. DO, DO % saturation, Chi, and OBS: GM0704, Z02.
203
-------
GM0704Z03
Temperature ( C)
10
15
20
Salinity
Sigrna T
12 15 18 21 24
Elapsed Time (hours)
27 30
33
10
Figure 3-14-21. Temperature, Salinity, and Sigma T: GM0704, Z03.
204
-------
GM0704Z03
10
£i_
a 15
20
Dissolved Oxygen (mg L
0
5
10
15
20
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21 24
Elapsed Time (hours)
27 30
33
Figure 3-14-22. DO, DO % saturation, Chi, and OBS: GM0704, Z03.
205
-------
GM0704Z04
Q 5
Temperature ( C)
Salinity
a 5
Sigma T
12 15 18 21 24 27
Elapsed Time (hours)
30 33 36
-15
10
Figure 3-14-23. Temperature, Salinity, and Sigma T: GM0704, Z04.
206
-------
GM0704Z04
Dissolved Oxygen (mg L
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
0 3
Optical Backscatter Voltage
6 9 12 15 18 21 24 27 3D 33 36
Elapsed Time (hours)
Figure 3-14-24. DO, DO % saturation, Chi, and OBS: GM0704, Z04.
207
-------
GM0708 Z02
Temperature ( C)
24
•s. 10
OJ
Cl
15
Salinity
S. 10
OJ
Cl
Sigrna T
12 15 IB 21 24
Elapsed Time (hours)
27 30 33
15
10
Figure 3-14-25. Temperature, Salinity, and Sigma T: GM0708, Z02.
208
-------
GM0708Z02
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscattcr Voltage, GM0708 ZD2
369
12 15 18 21
Elapsed Time (hours)
24 27 30 33
Figure 3-14-26. DO, DO % saturation, Chi, and OBS: GM0708, Z02.
209
-------
GM0708Z03
Temperature ( C)
Salinity1
Sigma T
12 15 18 21 24
Elapsed Time (hours)
27 30 33
10
Figure 3-14-27. Temperature, Salinity, and Sigma T: GM0708, Z03.
210
-------
GM0708 Z03
5
10
15
20
Dissolved Oxygen (mg L )
0
5
10
15
20
Dissolved Oxygen Saturation (%)
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
12 15 18 21 24
Elapsed Time (hours)
27 30
33
Figure 3-14-28. DO, DO % saturation, Chi, and OBS: GM0708, Z03.
211
-------
GM0708Z04
Temperature ( C)
Salinity
135
j 3D
I25
J20
15
Sigma T
125
120
15
10
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
Elapsed Time (hours)
Figure 3-14-29. Temperature, Salinity, and Sigma T: GM0708, Z04.
212
-------
GM0708 Z04
,_
Q 5
Dissolved Oxygen (mg L"
•a
CD
Q 5
Dissolved Oxygen Saturation (%)
150
Chlorophyll Autofluorescence Voltage
Optical Backscatter Voltage
0 3
6 9 12 15 18 21 24 27 30 33 36 39 42
Elapsed Time (hours)
Figure 3-14-30. DO, DO % saturation, Chi, and OBS: GM0708, Z04.
213
-------
5-75. Current Profiles, Shear, and Richardson Number (Ri) at Process Stations
The following series are time-depth contour plots of ADCP currents resolved into Northing and
Easting orthogonal components collected at the Process stations during 2006-2007. On each
cruise, 3 stations were occupied for -30-36 hours. The ADCP was continuously logging current
profiles, which were binned into 7 minute averages. Current shear was calculated from the raw
ADCP data. The Richardson number (Ri) was calculated using the physical structure interpolated
from periodic CTD casts (3-6 hour intervals).
214
-------
GM0609 Z01
Q. 10
Northing, cm s
15
Easting, cm s"
-20
Richardson Number
•s. 10
Shear, s
9 12 15
Elapsed Time (hours)
Figure 3-15-1. Currents, Shear, and Richardson Number: GM0609, Z01.
215
-------
GM0609Z02
HID
01
Q
Northing, cm s
,§
f 10
d>
O
15
Easting, cm s"
1 1 1 1
£ 10
Richardson Number
Shear, s
-1
12 15 18 21
Elapsed Time (hours)
24 27 30
Figure 3-15-2. Currents, Shear, and Richardson Number: GM0609, Z02.
216
-------
GM0609Z03
Northing, cm s
Easting, cm s"
Richardson Number
Shear, s
9 12 15 18
Elapsed Time (hours)
21 24
27
05
Figure 3-15-3. Currents, Shear, and Richardson Number: GM0609, Z03.
217
-------
GM0704Z02
Northing, cm s
0
5
,§
£ 10
o.
ffl
Q 15
Easting, cm s"
Richardson Number
Shear, s
-1
0 3
12 15 18 21
Elapsed Time (hours)
24 27 30 33
05
Figure 3-15-4. Currents, Shear, and Richardson Number: GM0704, Z02.
218
-------
GM0704Z03
20
Northing, cm s
Easting, cm s"
Richardson Number
Shear, s
10
15
20
il
12 15 18 21
Elapsed Time (hours)
24 27 30 33
05
Figure 3-15-5. Currents, Shear, and Richardson Number: GM0704, Z03.
219
-------
GM0704Z04
Northing, cm s"
I If lupin I
tfUMlllll
Easting, cm s"
Richardson Number
Shear, s
-1
0 3 6
12 15 18 21 24 27 30 33 36
Elapsed Time (hours)
Figure 3-15-6. Currents, Shear, and Richardson Number: GM0704, Z04.
220
-------
GM0708Z02
a. 10
Northing, cm s
10
15
Easting, cm s"
Richardson Number
Shear, s
-1
0369
12 15 18 21 24
Elapsed Time (hours)
27 30 33 36
05
Figure 3-15-7. Currents, Shear, and Richardson Number: GM0708, Z02.
221
-------
GM0708Z03
Northing, cm s
Easting, cm s"
Richardson Number
Shear, s
-1
12 15 18 21 24 27 30
Elapsed Time (hours)
Figure 3-15-8. Currents, Shear, and Richardson Number: GM0708, Z03.
222
-------
GM0708Z04
uj __
O 5
Northing, cm s
Easting, cm s"
Richardson Number
Shear, s
-1
I'.fOTJ1 -V^Mlf*'111 '"'r'1
i • * tt t
i^'itflffiw aliMMto. ')•
0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
Elapsed Time (hours)
05
Figure 3-15-9. Currents, Shear, and Richardson Number: GM0708, Z04.
223
-------
3-16. Surface and Bottom YSI Time Series at Process Stations
The following plots summarize data collected at process stations during 2006-2007. Autonomous
logging YSI 6600 instruments were deployed during station occupation and data were logged at
15 minute intervals. At some stations, only surface or bottom data were collected, whereas on
other occasions, both surface and bottom layers were monitored with paired deployments.
Parameters included water temperature (°C), salinity, chlorophyll (jig L"1), and turbidity (NTU).
224
-------
23
'S.
Q.
£•35
_c
~eo
in
1A •
r
_J _,i.M....^.«..^
Date/Time
Figure 3-16-1. YSI Time Series: GM0604, Z02.
225
-------
32 i
Dale/Time
Figure 3-16-2.YSI Time Series: GM0606, Z01.
226
-------
' Date/Time
Figure 3-16-3. YSI Time Series: GM0606, Z02.
227
-------
32
y
If 30
I
S.28 •
26
-Surface
62 -
31 -
c-
£30
5 29
|28
"27-
OR
s. .*. -_/V
^•••/V v**^
^^••"•"""""••""•••l
a I
8
£"6 -
fi
1 -
n
V. „
Date/Time
Figure 3-16-4. YSI Time Series: GM0606, Z03.
228
-------
24
8
7
-. 6
- 5
01
E 4
8 \
1
0
1
m°-8
^0.6
"§•0.4
| 0.2
u
14
12
10
8
6
•e 4 -
|2 2
_^ •
+~-
"^
-••
^*^^«*«^
,
\IO DAT>
\
£
3
DateTTi
Figure 3-16-5. YSI Time Series: GM0609, Z01.
229
-------
31
o
^30
I 29
H
28
34
32
-Surface
26 -
22
20
8
I 7
8
6
1 -I
| 0.8-
= 0.6 -
f 0.4-
| 0.2
U
-/
lilO DAT>
\
Figure 3-16-6. YSI Time Series: GM0609, Z02.
230
-------
Figure 3-16-7. YSI Time Series: GM0609, Z03.
231
-------
300
S250
5.200
Jl50
1100
*
imme
Date/TTme
Figure 3-16-8. YSI Time Series: GM0704, Z02.
232
-------
O)
8
a •
7 •
6 •
5 •
4 •
3 •
2 •
1 •
n .
!
i !
•
50
= 30
f 20
|io
0
0
5
= 4
S- 3
f 2-
Figure 3-16-9. YSI Time Series: GM0704, Z03.
233
-------
Q.
I
6
-fcJVJ ^W*N^^
1 1 1 1 1
Date/Tim
Figure 3-16-10. YSI Time Series: GM0704, Z04.
234
-------
Figure 3-16-11. YSI Time Series: GM0708, Z02.
235
-------
32
0)
3 30
i
£29
CL
I 28
27
38
.
32
•| 30
I28
26
24
10
_ 8
w 6
a
4
! I
i
80
£"70
§50
j?40 -
g-30
.o 20
J—
i
i
|
i
|
Date/Time
Figure 3-16-12. YSI Time Series: GM0708, Z03.
236
-------
«B
Hate/Time V
Date/Time
Figure 3-16-13. YSI Time Series: GM0708, Z04.
237
-------
APPENDIX A. PHYTOPLANKTON SPECIES LIST
Phytoplankton were identified in 309 samples taken at multiple stations over 9 cruises across the
shelf. The cruise(s) during which each species was observed is indicated.
Phytoplankton Species List
Taxon
Cyanobacteria
Anabaena sp
Aphanocapsa marina
Aphanocapsa sp
Aphanothece sp
Chroococcus minimus
Chroococcus sp
Lemmermanniella sp
Merismopedia tenuissima
Phormidium sp
Romeria leopoliensis
Chlorophyceae
Actinastrum hantzschii v.
subtile
Brachiomonas sp
Chlamydomonas sp
Closterium sp
Crucigenia quadrata
Kirchneriella lunaris
Oltmannsiella lineata
Oltsmannsiella viridia
Pachysphaera pelagica
Pyramimomas micron
Pyramimonas torta
Scenedesmus bicaudatus
Scenedesmus bijuga
(Keissler)
Lemmermann
(Keissler)
Lemmermann
Lemmermann
Lemmermann
Zimmermann 1930
W. Conrad & H.
Kufferath
(Guglielmetti)
Chodat
(Huber-Pestolozzi)
Pankow1986
X
X
X
X
X
X
X X
X
X X X X
X XX X
X
X X
X
X XX
xxxxxxxxx
XX XX
X
X XX
X X X X X X
X
X
X
X X
X
238
-------
Phytoplankton Species List
90
o
Taxon
Tetraselmis sp
Bacillariophyceae
(Diatoms)
Achnanthidium exiguum
Actinoptychus senarius
Amphiprora sulcata
Asterionellopsis glacialis
Asterolampra marylandica
Asteromphalus heptactis
Aulacoseira sp
Bacteriastrum delicatulum
Bacteriastrum elongatum
Cerataulina pelagica
Author
^*4 ro fO ^^ ^^ ^o ^^ ^^
^HOOOOOOO
oooooooo
gggggggg
XXXXXXXXX
Ehrenberg 1843
(O'Meara) Cleve
1894
(F. Castracane)
F.E. Round 1990
X
Cleve 1897
(Cleve) Hendey
1937
Grunow 1897,
(Gran) Hustedt
Chaetoceros affinis
Chaetoceros atlanticus
Chaetoceros atlanticus v
neapolitana
Chaetoceros brevis
Chaetoceros compressus
Chaetoceros concavicornis
Chaetoceros constrictus
Chaetoceros danicus
Chaetoceros decipiens
1930
Schutt 1895
Schutt 1895
Mangin 1917
Gran 1897
Cleve 1873
Chaetoceros didymus
Chaetoceros didymus V
anglicus
Chaetoceros didymus V
protuberans
Chaetoceros difficilis
(H.S. Lauder)H.H.
Gran & K. Yendo
(H.S. Lauder)H.H.
Gran & K. Yendo
Cleve 1900
X
X X X X X X
X
X X
X
X X
X
X
X
X
xxxxxxxxx
XX X X X X X
XX X
X
X
X XXX
XXX X
X
xxxxxxxxx
X
X
X
X X
XXX
X X
X
XXX
X
X XX
xxxxxxxxx
239
-------
Phytoplankton Species List
Taxon
Chaetoceros gracilis
Chaetoceros holsaticus
Chaetoceros laciniosus
Chaetoceros lorenziamis
Chaetoceros messanensis
Chaetoceros pelagicus
Chaetoceros pendulum
Chaetoceros peruvianus
Chaetoceros
pseudocurvise tus
Chaetoceros radicans
Chaetoceros socialis
Chaetoceros sp.
Chaetoceros subtilis
Chaetoceros tenuissimus
Cocconeis placentula v
lineata
Cocconeis scutellum
Corethron criophilum
Corethron criophilum
Coscinodiscus centralis V
pacifica
Coscinodiscus curvatulus
Coscinodiscus lineatus
Coscinodiscus marginatus
Coscinodiscus oculus-iridis
Coscinodiscus sp
Coscinodiscus wailesii
Cyclotella caspia?
Cyclotella litoralis
Cyclotella sp.
Author
S.L.
VanLandingham
1968
Schutt 1895
Grunow 1863
Castracane 1875
H.H. Gran
Brightwell 1856
Schutt 1895
(F. Schutt) A.I.
Proshkina-
Lavrenko
Cleve
A.F. Meunier
Karsten 1905
H.H. Gran & B.C.
Angst
A. Schmidt 1878
A. Schmidt 1878
M. Hajos
Ehrenberg 1854
Grunow 1878
Lange & Syvertsen
1989
^H O
«s ro
o o
O
ITJ
o
c\
o
o
VO
O
o
VO
O
c\ •*
o o
O O
90
o
o o o
X
X
X X
X X X X X
X
X
X
X
X X
X X
X X
X
X
X X
XXX
X
X
XXX
X
X X X X X
X
X
X
X
X
XX X
XX X
X
X
X
X
X X
X X X
X X X X X
X
X
X
XX
X
X
X
X
X X X
X X X
X X X
240
-------
Phytoplankton Species List
f"4 fO fO ON ^f vo ON
^H O O O O O O
90
o
oooooooo 2
gggggggg I
Taxon Author uuuuuuuu
(Ehrenberg)
Reimann & Lewin
Cylindrotheca closterium 1964 XXXXXXXXX
Dactyliosolen antarcticus Castracane 1886 X X X X X X X
(Bergon) G.R.
Dactyliosolen fragilissimus Hasle 1997 X X X X
(Ehrenberg) G.W.
Delphineis surirella Andrews 1981 X X X X X X
Diploneis sp XX
A. Schmidt) Cleve
Diploneis weissflogi 1894 X XX XXX
Ditylumbrightwellii (T. West) Grunow X X X X X X
Eucampia cornuta X
Eucampia groenlandica Cleve 1896 X
Eucampia groenlandica X
Eucampia zodiacus XXX
Eucampia zodiacus f
cylindricornis X XX
Eucampia zodiacus F
cylindrocornis E.E. Syvertsen X
Witkowski &
Fragilaria improbula Lange-Bertalot X XX
Fragilariopsis pseudonana XXX
(Cleve) G.R. Hasle
Guinardia delicatula 1997 X XXXXXXX
(Castracane) H.
Guinardia flaccida Peragallo 1892 X XXXXXXX
(Stolterfoth) G.R.
Guinardia striata Hasle 1997 XXX X XX
Haslea trompii X
Haslea wawrikae XX X
Grunow ex Van
Hemiaulus hauckii Heurck 1882 X XXXXXXX
Hemiaulus sinensis Greville X X X X X X X
Lauderia annulata Cleve 1873 XX XX
Lauderia delicatula X
241
-------
Phytoplankton Species List
^H O
Taxon
Leptocylindrus danicus
Leptocylindrus minimus
Lioloma pacificum
Meuniera membranacea
Navicula membranacea
Navicula sp
Neodelphineis pelagica
Nitzschia fusiformis
Nitzschia longissima
Nitzschia lorenziana
Nitzschia nana
Nitzschia panduriformis v
continua
Nitzschia reversa
Nitzschia ruda
Nitzschia sicula
Nitzschia sp
Odontella aurita
Odontella mobiliensis
Odontella sinensis
Pinnularia sp
Planktoniella sol
Pleurosigma normanii
Pleurosigma sp
Proboscia alata
Psammodiscus nitidus
Pseudoguinardia recta
Author
Gran 1915
(E. Cupp) G.R.
Hasle
(Cleve) P.C. Silva
1990
(Cleve) P.C. Silva
1990
(Brebisson in
Kiitzing) Ralfs
1861
Cholnoky 1968
(Lyngbye) C.
Agardh 1832
(J.W. Bailey)
Grunow 1884
(Wallich) Schutt
1892
Ralfs 1861
(Brightwell)
Sundstrom
von Stosch 1986
X
X X
X
0509
0604
vo c\ •*
o o o
\o vo i^
o o o
oooooooo
X X X X
X
X
X
X
X
X
X
X
X X X X
X
X
X
X
X
90
o
1^
o
o
X XXX
X X X X X
xxxxxxxxx
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X X X X
xxxxxxxxx
X X
X
XXX
X X
X
242
-------
Phytoplankton Species List
Taxon
Pseudo-nitzschia
calliantha
Pseudo-nitzschia cuspidata
Pseudo-nitzschia
delicatissima
Pseudo-nitzschia
multiseries
Pseudo-nitzschia
pseudodelicatissima
Pseudo-nitzschia pungens
Pseudo-nitzschia sp
Pseudosolenia calcar-avis
Rhizosolenia fallax
Rhizosolenia hebetata
Rhizosolenia hebetata f
hiemalis
Rhizosolenia hebetata F
semispina
Rhizosolenia imbricata
Rhizosolenia imbricata v
shrubsolei
Rhizosolenia setigera
Skeletonema costatum
Thalassionema lineatum
Thalassionema
nitzschioides
Thalassiosira excentrica
Thalassiosira hyalina
Thalassiosira oestrupii
Thalassiosira rotula
Thalassiosira sp
Author
(Hasle &
Lundholm 2005,
Lundholm et al
2006)
G.R. Hasle 1965
(Cleve) Heiden
1928
Hasle 1995
Hasle 1993
Hasle
(Schultze)
Sundstrom
Sundstrom 1986
Bailey
(Hensen) Gran
1905
Brightwell
(Greville) Cleve
1878
(Grunow)
Mereschkowsky
1902
(Ehrenberg) Cleve
(Grunow) Gran
1897
(Ostenfeld) Hasle
1972
Meunier 1910
O
ro
o
fO ON
o o
VO C\
o o
o
t-~
o
90
O
o o o o o
§ § § § § § §
X X
XX X X X X
X X X X X X
X
x
X
xxxxxxxx
X X X X X X
xxxxxxxx
X XXX
X X
X
X X X X
X
X
X
X
X
X
X
X
X X
X
XXX
x
x
X
xxxxxxxx
XX XXX
xxxxxxxx
X XXXXXX
X X
X X
X X
xxxxxxxx
X X
X X X X X
243
-------
Phytoplankton Species List
Taxon
Thalassiothrix frauenfeldii
Thalassiothrix longissima
Chrysophyceae
Apedinella spinifera
Ochromonas sp
Prymnesiophyceae
Chrysochromulina minor
Prymnesium sp
Euglenophyta
Euglena sp
Eutreptia lanowii?
Eutreptia sp.
Cryptophyceae
(Cryptomonads)
Chilomonas sp
Chroomonas sp
Cryptomonas caudata?
Cryptomonas sp
Hillea fusiformis
Rhodomonas salina
Teleaulax acuta?
Dinophyceae
(Dinoflagellates)
Alexandrium cohorticula
Alexandrium monilatum
Alexandrium sp
Amphidinium acutissimum
Amphidinium acutum
Amphidinium extensum
Amphidinium globosum
^H O
«S fO
o o
o
ITJ
O
o
ITJ
O
o
VO
o
o
VO
o
o
VO
o
Author u
(Grunow, in Van
Heurck) G.R. Hasle X
Cleve & Grunow
1880
(Throndsen)
Throndsen 1971
Manton & Clarke
1955
X
X
X
X
X
Steuer 1904
X X
XX X
Massart
Schiller 1925
D.R.A. Hill & R.
Wetherbee 1989
D.R.A. Hill 1991
X
X
Balech
Schiller 1933
Lohmann
Lohmann
Schroder
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
o
t-~
o
X
X
90
o
XXX
X XX
X X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
244
-------
Phytoplankton Species List
Taxon
Amphidinium latum
Amphidinium schroderi
Amphidinium sp
Ceratium furca
Ceratium hirundinella
Ceratium kofoidii
Ceratium lineatum
Ceratium macroceros
Ceratium massilieme
Ceratium setaceum
Ceratium tripos
Chaetoceros anastomosans
Dictyocha speculum
Dinophysis acuminata
Exuviaella dactylus
Exuviaella vaginula
Gymnodinium fuscum
Gymnodinium fusus
Gymnodinium lebourii
Gymnodinium minor
Gymnodinium rotundatum
Gymnodinium sanguineum
Gymnodinium sp
Gyrodinium estuariale
Gyrodinium fusiforme
Gyrodinium sp
Karenia brevis
Oxytoxum laticeps
Oxytoxum parvum
Oxytoxum sceptrum
Oxytoxum sp
^HO
fsro
oo
Author
L. Maranda & Y.
Shimizu
X
X
(O.F. Mullet)
Dujardin
E.G. J0rgensen
(Ehrenberg) Cleve
X
Claparede &
Lachmann
(Stein) Schutt 1895
Schutt
X
Hulbert
(C.C. Davis) G.
Hansen & 0.
Moestrup
Schiller
Schiller
(Stein) Schroder
X X
X
X
O
irj
o
X
X
X
O
irj
o
O
vo
o
O
vo
o
O
vo
o
X
X X
X
X
X
X
O
i^
o
X X
X
X
X
90
o
o
X XX
X X X X X X X
X X X X X
X
X
X
X
XXX
X X X X
X X X X
X X
X
X
X X
X X X X X X X
X X
X X X X X
X X X X X
XXX XX
X X
X XXX
X
X X X X
245
-------
Phytoplankton Species List
Taxon
Oxytoxum sphaeroideum
Oxytoxum variabile
Oxytoxum viride
Peridinium sp
Podolampas palmipes
Polykrikos schwartzii
Porella per/or ata
Pronoctiluca rostratum
Pronoctiluca spinifera
Prorocentrum compressum
Prorocentrum gracile
Prorocentrum micans
Prorocentrum minimum
Prorocentrum scutellum
Prorocentrum sp
Prorocentrum
sphaeroideum
Protoperidinium brevipes
Protoperidinium conicum
Protoperidinium
depressum
Protoperidinium diver gens
Protoperidinium globulum
Protoperidinium gracile
Protoperidinium grande
Protoperidinium
latispinum
Protoperidinium lebourae
Protoperidinium
minisculum
Protoperidinium pallidum
Protoperidinium
pellucidum
Protoperidinium pyriforme
Protoperidinium pyriforme
Protoperidinium
quarnerense
Author
Schiller
Butschli
Schutt
Ehrenberg
(Pavillard) J.
Schiller
Schroder
Schiller
(Paulsen) Balech
(Gran) Balech
(Ehrenberg) Balech
(Kofoid) Balech
^H O O
o o o
§ § §
X
X
X X
XXX
X
X X
X X
X
X
X
X
O\ ^ vo O\ ^
O O O O O
o o o o o
§ § § § §
X
X X X X
X X
X X
X
X
X X
XX X
XXX
90
o
X
X
X
X
X
X X X X X
XXX
X X
X X
X X X X X X
X
X
X XX
X X X X X
X
X X X X X
X
X X X X X
X
X
(Schroder) Balech
X X
X
X X
246
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Phytoplankton Species List
^HOOOOOOO
oooooooo
90
O
Taxon Author OOOOOOOO
Protoperidinium
quiquecorne X
Protoperidinium rostratum XX X
Protoperidinium sp X X X X X X X
Protoperidinium
spinulosum X
Scrippsiella trochoidea M. Montresor XX XX
Warnowia sp X
247
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APPENDIX B. CRUISE PARTICIPANTS
Cruise
Legl
Leg 2
GM0212
GM0303
GM0306
GM0311
GM0404
GM0503
GM0509
GM0604
Frank Blue
Jed Campbell
Darrin Dantin
Jed Campbell
Andy Juhl
Mike Murrell
Roman Stanley
Jed Campbell
Jim Hagy
Jan Kurtz
Roman Stanley
Sherry Vickery
Jed Campbell
Rick Greene
Jan Kurtz
Mike Murrell
Jed Cambell
James Cherry
Jan Kurtz
Survey
2-10 Dec 2002
Jan Kurtz
Mike Murrell
Jim Watts
Survey
17 -24 Mar 2003
Sherry Vickery
Beth Hinchey (AED)
Phil Jennings (R6)
Survey
9-1 6 June 2003
JeanBrochi(Rl)
Bill Cox (R4)
Mariama Dover (R6)
Gloria Vaughn (R6)
Survey
5-12 Nov 2003
Roman Stanley
Sherry Vickery
Lee Anderson (MED)
Sam Miller (MED
Survey
2-6 Apr 2004
Heather Reed
Jessica Rivord
Survey
2 1 Mar -1 Apr 2005
Alex Almario John Lehrter
Brad Blackwell Jessica Rivord
Jed Campbell Roman Stanley
Jim Hagy Sherry Vickery
Survey
26Sep-9Oct2005
Alex Almario John Lehrter
Brad Blackwell Mike Murrell
Jed Campbell Jessica Rivord
James Cherry Roman Stanley
George Craven Sherry Vickery
Richard Devereux Lee Anderson (MED)
Tony DiGirolamo Nancy Andrews (OST)
Jim Hagy John Hardin (Batelle)
Alex Almario
James Cherry
George Craven
Richard Devereux
Laura Dobbins
Jim Hagy
Jan Kurtz
Process
5-1 2 April 2006
John Lehrter
Mike Murrell
Bob Quarles
Roman Stanley
Sherry Vickery
Lee Anderson (MED)
Pete Eldridge (WED)
Jed Campbell
James Cherry
Rick Greene
Jed Campbell
Jim Hagy
Jan Kurtz
Roman Stanley
Jed Campbell
Rick Greene
Mike Murrell
Roman Stanley
Jed Campbell
Jim Hagy
Jan Kurtz
Mike Murrell
Survey
10-1 2 Dec 2002
Larry Goodman
Andy Juhl
Sherry Vickery
Survey
24 -31 Mar 2003
Ray Wilhour
Marty Chintala (AED)
Kathy El Said (FDA)
Survey
1 6-2 Uune 2003
Sherry Vickery
Mike Bira (R6)
Steve Blackburn (R4)
Ken league (R6)
Survey
12-1 9 Nov 2003
Roman Stanley
Sherry Vickery
Lee Anderson (MED)
Sam Miller (MED
James Cherry
George Craven
Laura Dobbins
Jan Kurtz
John Lehrter
Jan Kurtz
Survey
12-1 7 April 2006
Mike Murrell
Leah Oliver
Roman Stanley
Ray Wilhour
Lee Anderson (MED)
248
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Cruise
GM0606
Jed Campbell
James Cherry
Rick Greene
Jim Hagy
Brandon Jarvis
Jan Kurtz
Joe Moss
Legl
Survey
6-12 June 2006
Mike Murrell
Mary Mutz
Leah Oliver
Roman Stanley
Lee Anderson (MED)
Xianghui Guo (UGA)
Justin Hartmann (UGA)
Alex Almario
Mace Barron
George Craven
Richard Devereux
Jim Hagy
Jan Kurtz
John Lehrter
Leg 2
Process
13-18 June 2006
Mike Murrell
Mary Mutz
Bob Quarles
Jeanne Scott
Roman Stanley
Sherry Vickery
Lee Anderson (MED)
GM0609
Amy Baldwin
Jed Campbell
Fred Genthner
Nate LeMoine
Jim Hagy
Jan Kurtz
John Lehrter
Survey
5-12 Sept 2006
Roman Stanley
Sherry Vickery
Tina Hendon (R6)
Lee Anderson (MED)
Rebecca Green (NRL)
Feizhou Chen (UGA)
Zhongyong Gao (UGA)
David Beddick
George Craven
Richard Devereux
Jim Hagy
Jan Kurtz
John Lehrter
Cheryl McGill
Mike Murrell
Process
12-20 Sept 2006
Bob Quarles
Clay Peacher
Jeanne Scott
Roman Stanley
Sherry Vickery
Lee Anderson (MED)
Brian Fry (LSU)
Sara Green (LSU)
GM0704
24
Alex Almario
David Beddick
George Craven
Richard Devereux
Jim Hagy
Jan Kurtz
John Lehrter
Mike Murrell
Process
April-1 May 2007
Bob Quarles
Jessica Rivord
Jeanne Scott
Roman Stanley
Lee Anderson (MED)
Melissa Baustian (LSU)
Pete Eldridge (WED)
Brian Fry (LSU)
David Beddick
George Craven
Jim Hagy
Nathan LeMoine
Jan Kurtz
Chris Main
Mary Mutz
Leah Oliver
Survey
2-8 May 2007
Jessica Rivord
Roman Stanley
Lee Anderson (MED)
Feizhou Chen (UGA)
Wei-Jen Huang (UGA)
Laurie Lindquist (R4)
Jamie Steichen (TAMUG)
GM0708
David Beddick
George Craven
Amanda Hott
Jan Kurtz
John Lehrter
Chris Main
Kathy Porter
Jessica Rivord
George Smith
Survey
18-24Aug2007
Blake Schaeffer
Roman Stanley
Federico Alvarez (TAMUG)
Lee Anderson (MED)
Feizhou Chen (UGA)
Justin Hartmann (UGA)
Laurie Lindquist (R4)
24
David Beddick
Jed Campbell
Richard Devereux
Rick Greene
Jim Hagy
Jan Kurtz
John Lehrter
Mike Murrell
Leah Oliver
Process
Aug-lSep2007
Jessica Rivord
Jeanne Scott
Roman Stanley
Sherry Vickery
Blake Schaeffer
Lee Anderson (MED)
Brandon Boyd (LSU)
Brian Fry (LSU)
Rebecca Green (NRL)
AED: US EPA, Atlantic Ecology Division, Narragansett, RI
FDA: US Food and Drug Administration, Dauphin Island, AL
LSU: Louisiana State University, Baton Rouge, LA
MED: US EPA, Mid-Continent Ecology Division, Duluth, MN
NRL: Naval Research Laboratory, Stennis Space Center, MS
OST: US EPA, Office of Water, Office of Science and Technology, Washington, DC.
Rl: US EPA, Region 1, Boston, MA
R4: US EPA Region 4, Atlanta, GA
R6: US EPA, Region 6, Dallas, TX
TAMUG: Texas A&M University, Galveston, TX
UGA: University of Georgia, Athens GA
WED: US EPA, Western Ecology Division, Newport, OR
249
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APPENDIX C. PUBLICATIONS RESULTING FROM THIS PROJECT
The hypoxia field program has resulted in an earlier data report plus a number of peer-reviewed
publications. Included here is the list of all publications to date, their complete citations and
abstracts. We direct the reader to these papers for a more thorough interpretation of the data.
Cai, W. -I, X. Hu, W. -J. Huang, M. C. Murrell, J. C. Lehrter, S. E. Lohrenz, W. -C. Chou, W.
Zhai, J. T. Hollibaugh, Y. Wang, P. Zhao, X. Guo, K. Gundersen, M. Dai, G. -C. Gong
(2011). Eutrophication and high atmospheric pCO2 enhance ocean acidification and
denitrification. Nature Geoscience. 4:766-770, DOT: 10.1038/NGEO1297.
Human inputs of nutrients to coastal waters can lead to the excessive production of algae, a process known as
eutrophication. Microbial consumption of this organic matter lowers oxygen levels in the water. In addition, the
carbon dioxide produced during microbial respiration increases acidity. The dissolution of atmospheric carbon
dioxide in ocean waters also raises acidity, a process known as ocean acidification. Here, we assess the combined
impact of eutrophication and ocean acidification on acidity in the coastal ocean, using data collected in the
northern Gulf of Mexico and the East China Sea—two regions heavily influenced by nutrient-laden rivers. We show
that eutrophication in these waters is associated with the development of hypoxia and the acidification of subsurface
waters, as expected. Model simulations, using data collected from the northern Gulf of Mexico, however, suggest
that the drop in pH since pre-industrial times is greater than that expected from eutrophication and ocean
acidification alone. We attribute the additional drop in pH— of 0.05 units—to a reduction in the ability of these
carbon dioxide-rich waters to buffer changes in pH. We suggest that eutrophication could increase the susceptibility
of coastal waters to ocean acidification.
Devereux, R., J. C. Lehrter, D. L. Beddick, D. F. Yates, B. M. Jarvis (in revision). Electron
acceptor cycling in muddy Louisiana continental shelf sediments in relation to bottom
water oxygen concentrations
Although the contributions ofbenthic biogeochemistry, especially sulfate reduction, to the development and effects
of hypoxia that occurs seasonally in the northern Gulf of Mexico on the Louisiana continental shelf (LCS) have
received wide attention, limited information is available on the importance ofsuboxic metal cycling in the region.
Manganese, iron, and sulfur cycling were studied in muddy sediments at three stations on the Louisiana continental
shelf (LCS). The sampling locations spanned 320 km along the 20 m isobath in regions that experience summertime
bottom water hypoxia and were visited during five cruises between the spring of 2006 and summer of 2007.
Porewater Mn andFe2+ concentrations (up to 220 and 300 fimol L-l, respectively) differed with station and bottom
water oxygen levels (203 mmol m-3 in spring to 2.5 mmol m-3 in summer). Station Z02 on the eastern LCS, south of
Terrebonne Bay, had highest porewater Mn concentrations in the spring and highest Fe2+ concentrations during
summer, whereas porewater Mn andFe2+ concentrations at station Z03, 160 km further west, were both highest
during summer. The proportion of total oxalate extracted iron obtained as Fe(II) across the three stations was
higher (p < 0.001) in summer (0.52) than spring (0.25) suggesting wide-scale annual cycling of iron on the LCS.
Porewater concentrations of ortho-phosphate were as much as 30 fold higher in the summer than spring and likely
reflect mobilization of phosphorus through iron reduction. Sulfate reduction rates (1.0 to 8.4 mmol m-2 d-1) were
highest during hypoxic conditions at Z02 south of Terrebonne and were not observed to vary with water column
oxygen concentrations at Z03 on the western shelf station where potential rates for Mn andFe reduction were
determined to be greatest. The results demonstrate sulfate reduction rates, the potential for metal oxide reduction,
and changes in sediment redox in relation to bottom water oxygen concentrations vary regionally in the LCS
hypoxic zone.
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Fry B., D. Justic', P. Riekenberg, E. Swenson, R. E. Turner, L. Wang, L. Pride, N. N. Rabalais,
J. C. Kurtz, J. C. Lehrter, M. C. Murrell, E. H. Shadwick, B. Boyd (in review). Carbon
dynamics on the Louisiana continental shelf and cross-shelf feeding of hypoxia. Estuaries
and Coasts
Large-scale hypoxia regularly develops during the summer on the Louisiana continental shelf. Traditionally,
hypoxia has been linked to the vast winter and spring nutrient inputs from the Mississippi River and its distributary,
the Atchafalaya River. However, some older sediment trap results and recent models indicate low retention of algal
carbon produced from the riverine nutrients, so that much of the algal carbon load may be exported off the shelf. We
used data from five late July shelfwide cruises from 2006 to 2010 to examine carbon production and retention on the
Louisiana shelf. During these summer times of moderate river flows, shelfwide pH and POC (particulate organic
carbon) consistently showed strong signals for net autotrophy in low salinity (<25) waters near the river mouths.
POC rapidly disappeared from surface waters in the low and mid salinity ranges without producing strong
respiration signals in surface waters, indicating rapid POC removal via grazing and sedimentation in near-river
regions. This rapid removal indicates highly efficient algal retention by the shelf ecosystem. Updated carbon export
calculations for local estuaries and a preliminary shelfwide carbon budget agree with older concepts that offshore
hypoxia is linked strongly to nutrient loading from the Mississippi River, but a new emphasis on cross- shelf
dynamics emerged in this research. Cross-shelf transects indicated that river-influenced nearshore waters <15 m
deep are strong sources of net carbon production, with currents and wave-induced resuspension likely transporting
this POC offshore to fuel hypoxia in adjacent mid-shelf bottom waters.
Greene, R. M., J. C. Lehrter, J. D. Hagy, III (2009). Multiple regression models for hindcasting
and forecasting midsummer hypoxia in the Gulf of Mexico. Ecological Applications
19:1161-1175
A new suite of multiple regression models was developed that describes relationships between the area of bottom
water hypoxia along the northern Gulf of Mexico and Mississippi-Atchafalaya River nitrate concentration, total
phosphorus (TP) concentration, and discharge. Model input variables were derived from two load estimation
methods, the adjusted maximum likelihood estimation (AMLE) and the composite (COMP) method, developed by the
U.S. Geological Survey. Variability in midsummer hypoxic area was described by models that incorporated May
discharge, May nitrate, and February TP concentrations or their spring (discharge and nitrate) and winter (TP)
averages. The regression models predicted the observed hypoxic area within 630%, yet model residuals showed an
increasing trend with time. An additional model variable, Epoch, which allowed post-199 3 observations to have a
different intercept than earlier observations, suggested that hypoxic area has been 6450 km2 greater per unit
discharge and nutrients since 1993. Model forecasts predicted that a dual 45% reduction in nitrate and TP
concentration would likely reduce hypoxic area to approximately 5000 km2, the coastal goal established by the
Mississippi River/Gulf of Mexico Watershed Nutrient Task Force. However, the COMP load estimation method,
which is more accurate than the AMLE method, resulted in a smaller predicted hypoxia response to any given
nutrient reduction than models based on the AMLE method. Monte Carlo simulations predicted that five years after
an instantaneous 50% nitrate reduction or dual 45% nitrate and TP reduction it would be possible to resolve a
significant reduction in hypoxic area. However, if nutrient reduction targets were achieved gradually (e.g., over 10
years), much more than a decade would be required before a significant downward trend in both nutrient
concentrations and hypoxic area could be resolved against the large background ofinterannual variability. The
multiple regression models and statistical approaches applied provide improved capabilities for evaluating dual
nutrient management strategies to address Gulf hypoxia and a clearer perspective on the strengths and imitations
of approaching the problem using regression models.
Guo, X., W. -J. Cai, W. -J. Huang, Y. Wang, F. Chen, M. C. Murrell, S. E. Lohrenz, L. -Q
Jiang, M. Dai, J. Hartmann, R. Gulp (2012). CO2 dynamics and community metabolism
in the Mississippi River plume. Limnology and Oceanography 57:1-17
Dissolved inorganic carbon (DIC), total alkalinity (TAlk), pH, and dissolved oxygen (DO) were determined in the
Mississippi River plume during five cruises conducted in the spring, summer, and fall. In contrast to many other
large rivers, both DIC and TAlk were higher in river water than in seawater. Substantial losses of DIC, relative to
TAlk, occurred within the plume, particularly at intermediate salinities. DIC removal was accompanied by high DO,
high pH, and nutrient depletion, and was attributed to high phytoplankton production. As a result, the carbonate
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saturation in the plume became much higher than in ocean and river waters. A mixing model was used to determine
DIC removal. We provide evidence that the use of a two-end-member (river and ocean) mixing model was valid
during late summer and fall (low discharge period). However, for other periods we used salinity and TAlk to
delineate a mixing model that included two river end members and an ocean end member. Net community
production rates in the plume, estimated using a box model, peaked in the summer and were among the highest
reported to date for large river plumes. In the summer and fall, biological production in the river plume consumed a
majority of the available nutrients, whereas during the spring only a small fraction of the available nutrients were
consumed in the plume. Biological production was the dominant process influencing pH and carbonate saturation
state along the river-ocean gradient, whereas physicochemical dynamics of mixing played an important role in
controlling the TAlk and DIC distributions of this large river plume.
Kurtz J. C., M. K. Hein, J. C. Lehrter, B. A. Schaeffer, M. C. Murrell, R. M. Greene (in
revision). Variability of phytoplankton community structure, biomass, and diversity on
the Louisiana continental shelf, TEA, TEA.
Phytoplankton communities on the Louisiana continental shelf (LCS) are influenced by nutrient loading from the
Mississippi and Atchafalaya rivers and the resulting enhanced phytoplankton biomass contributes to large areas of
seasonal hypoxia in the region. A series samples were collected during spring and fall to characterize the
phytoplankton communities in the region as how they change in response to nutrient loading and water quality
conditions. Diatoms dominated the phytoplankton community in both seasons, accounting for 64-97% of numerical
abundance and 73-98% of total biovolume in surface samples, with Chaetocerous, Skeletonema, and the potentially
harmful algae genera Pseudo-nitzschia dominant in both seasons. During spring phytoplankton biovolume was
higher than during fall; and the spring. 2005 samples had the highest species diversity. These coupled water-
quality'/phytoplankton community data may allow for more accurate model parameterization of community
attributes on the LCS for predictive models. Rather than the six phytoplankton categories currently used for model
simulations ranging in size from 1.09-1.25 x 103 jjLm, our data indicated that much larger species were dominant,
including large genera like Cosinodiscus (2.6-1000x 103 ^m) andDitylum (11.3-176x 103 jjLm). Incorporating the
results of these community studies, and simplifying the category structure may provide more accurate and precise
productivity models and improve the linkages between phytoplankton production and incidence of hypoxia on the
LCS.
Lehrter J. C., D. L. Beddick, Jr., R. Devereux, D. F. Yates, M. C. Murrell (2012). Sediment-
water fluxes of dissolved inorganic carbon, O2, nutrients, and N2 from the hypoxic
region of the Louisiana continental shelf. Biogeochemistry 109:233-252.
Globally, hypoxic areas (<63 mmol O2 m-3) in coastal waters are increasing in number and spatial extent. One of
the largest coastal hypoxic regions has been observed during the summer in the bottom-water of the Louisiana
continental shelf. The shelf receives the sediments, organic matter, and nutrients exported from the Mississippi River
watershed, and much of this material is ultimately deposited to the sea floor. Hence, quantifying the rates of
sediment-water dissolved inorganic carbon (DIC), oxygen (O2), and nutrient fluxes is important for understanding
how these processes relate to the development and maintenance of hypoxia. In this study, the sediment-water fluxes
of DIC, O2, nutrients, andN2 (denitrification) were measured on the Louisiana shelf during six cruises from 2005
to 2007. On each cruise, three to four sites were occupied in or directly adjacent to the region of the shelf that
experiences hypoxia. DIC fluxes, a proxy for total sediment respiration, ranged from 7.9 to 21.4 mmol m-2 day-1 but
did not vary significantly either spatially or as a function of bottom-water O2 concentration. Overall, sediment
respiration and nutrient flux rates were small in comparison to water-column respiration and phytoplankton
nutrient demand. Nitrate fluxes were correlated with bottom water O2 concentrations (r = 0.69), and there was
evidence that decreasing O2 concentrations inhibited coupled nitrification-denitrification. Denitrification rates
averaged 1.4 mmol N m-2 day-1. Scaled to the area of the shelf, the denitrification sink represented approximately
39% of the N load from the Mississippi River watershed. The sediment-water fluxes reported from this study add
substantial information on the spatial and temporal patterns in carbon, O2, and nutrient cycling available for the
Louisiana continental shelf and, thus, improve the understanding of this system.
Lehrter, J. C, B. Fry, M. C. Murrell (accepted). Potential contribution of microphytobenthos
production to sub-pycnocline O2 dynamics in the hypoxic region of the Louisiana
continental shelf. Bulletin of Marine Science
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Over much of the Louisiana shelf, the water-column is entirely euphotic during spring and summer. This condition
provides the potential for high rates of benthic primary production and photo synthetic O2 production by the
microphytobenthos (MPB). In this study, we evaluate the hypothesis that MPB production substantially contributes
to the carbon and O2 budgets of the seasonally hypoxic (O2 < 63 mmol m-3) bottom waters. Observed MPB
production rates ranged from 0.0 to 5.9 mmol O2 m-2 d-1 across 4 sites selected based on their proximity to
Mississippi and Atchafalaya River inputs and corresponding light attenuation (KPAR, averages range from 0.15 to
0.52 m-1). Highest rates were oberved at sites with lowest KPAR. On the western shelf, where the lowest KPAR
were observed, MPB O2 production rates were observed to be greater than sediment O2 respiration. A simple
scaling calculation based on shelf-wide measurements of KPAR, bottom depth, and MPB production, suggested that
MPB communities strongly influence net sediment O2 exchanges on the western shelf. These findings provide a
more precise understanding of the processes involved in the development ofhypoxia, which is necessary to improve
prediction and potential mitigation of human activities contributing to coastal hypoxia.
Lehrter, J. C., D. -S. Ko, M. C. Murrell, J. D. Hagy, B. A. Schaeffer, R. M. Greene, R. W. Gould,
B. Penta. (2013). Nutrient distributions, transport pathways, and fate on the inner margin
of a river-dominated continental shelf J. Geophysical Research. 118:4822-4838.
Physical and biogeochemical processes determining the distribution and fate of nutrients delivered by the
Mississippi and Atchafalaya rivers to the inner Louisiana continental shelf (LCS) were examined using a three-
dimensional hydrodynamic model and observations of hydrography, nutrients, and organic carbon collected during
12 shelf-wide cruises. Two specific aspects of nutrient transport and fate on the inner LCS (< 50 m depth) were
evaluated: 1) along shelf and across shelf transports and; 2) sinks and sources of nutrient species. Nutrient and
organic carbon transport pathways were predominantly westward along the shelf. The westward export of dissolved
inorganic nitrogen (DIN) was calculated to be about one-quarter the combined DIN load from the Mississippi and
Atchafalaya rivers, whereas the westward export of dissolved organic nitrogen (DON) was 2.8-fold larger than the
combined DON load from the rivers. Different from dissolved inorganic nutrients, for which the rivers were the
primary transport pathway to the shelf, the dominant transport pathway to the inner shelf for organic nutrients was
advection from offshore. Net transformations from inorganic to organic nutrients were evident at salinity of 20 to
30. Above salinity of 30 organic nutrients were the dominant forms. Overall, we estimated that the inner LCS was a
net sink for total nitrogen in the amount of-3.14 mmol N m-2 d-1 and net sink for total phosphorus in the amount of
-0.28 mmol P m-2 d-1 These sinks were equivalent to 33% and 59% of the total N and P transports, respectively,
delivered to the inner LCS.
Lehrter, J. C., M. C. Murrell, and J. C. Kurtz (2009). Interactions between Mississippi River
inputs, light, and phytoplankton biomass and phytoplankton production on the Louisiana
continental shelf. Continental Shelf Research 29:1861-1872.
We examined the effects of freshwater flow and light availability on phytoplankton biomass and production along
the Louisiana continental shelf in the region characterized by persistent spring- summer stratification and
widespread summer hypoxia. Data were collected on 7 cruises from 2005 to 2007, and spatially-averaged estimates
of phytoplankton and light variables were calculated for the study area using Voronoi polygon normalization. Shelf-
wide phytoplankton production ranged from 0.47 to 1.75 mg C m-2 d-1 across the 7 cruises. Shelf-wide average
light attenuation (kd) ranged from 0.19-1.01 m-1 and strongly covaried with freshwater discharge from the
Mississippi and Atchafalaya Rivers (R2 =0.67). Interestingly, we observed that the euphotic zone (as defined by the
1% light depth) extended well below the pycnocline and to the bottom across much of the shelf. Shelf-wide average
chlorophyll a (chl a) concentrations ranged from 1.4 to 5.9 mg m-3 and, similar to kd, covaried with river discharge
(R2=0.83). Also, chl a concentrations were significantly higher in plume versus non-plume regions of the shelf.
When integrated through the water-column, shelf-wide average chl a ranged from 26.3 to 47.6 mg m-2, but did not
covary with river discharge, nor were plume versus non-plume averages statistically different. The high integrated
chl a in the non-plume waters resulted from frequent sub-pycnocline chl a maxima. Phytoplankton production rates
were highest in the vicinity of the Mississippi River bird's foot delta, but as with integrated chl a were not
statistically different in plume versus non-plume waters across the rest of the shelf. Based on the vertical
distribution of light and chl a, a substantial fraction of phytoplankton production occurred below the pycnocline,
averaging from 25% to 50% among cruises. These results suggest that freshwater and nutrient inputs regulate shelf-
wide kd and, consequently, the vertical distribution of primary production. The substantial below-pycnocline
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primary production we observed has not been previously quantified for this region, but has important implications
about the formation and persistence ofhypoxia on the Louisiana continental shelf.
Murrell, M. C., R. M. Greene, J. D. Hagy III, J. C. Kurtz, and J. C. Lehrter. 2007. Gulf of
Mexico Hypoxia: 2002-2005 Survey Report. U.S. Environmental Protection Agency,
EPA/600/X-07/016, Washington, DC. 124 p.
No abstract.
Murrell, M. C. and J. C. Lehrter (2011). Sediment and lower water column respiration in the
seasonally-hypoxic region of the northern Gulf of Mexico. Estuaries and Coasts 34:912-
924.
We report integrated measurements of sediment oxygen consumption (SOC) and bottom water plankton community
respiration rates (WR) during eight cruises from 2003 to 2007 on the Louisiana continental shelf (LCS) where
hypoxia develops annually. Averaged by cruise, SOC ranged from 3.9 to 25.8 mmol O2 m—2 day-1, whereas WR
ranged from 4.1 to 10.8 mmol O2 m—3 day-1. Total below pycnocline respiration rates ranged from 46.4 to 104.5
mmol O2 m—2 day-1. In general, below-pycnocline respiration showed low variability over a large geographic and
temporal range, and exhibited no clear spatial or inter annual patterns. SOC was strongly limited by dissolved
oxygen (DO) in the overlying water; whereas, WR was insensitive to low DO, a relationship that may be useful for
parameterizing future models. The component measures, WR and SOC, were similar to most prior measurements,
both from the LCS and from other shallow estuarine and coastal environments. The contribution of SOC to total
below-pycnocline respiration averaged 20 ± 4%, a finding that differs from several prior LCS studies, but one that
was well supported from the broader estuarine and oceanic literature. The data reported here add substantially to
those available for the LCS, thus helping to better understand oxygen dynamics on the LCS.
Murrell, M. C., R. S. Stanley, J. C. Lehrter, J. D. Hagy (2013). Plankton community respiration,
net ecosystem metabolism, and oxygen dynamics on the Louisiana continental shelf:
implications for hypoxia. Continental Shelf Research 52:27-38
We conducted a multi-year study of the Louisiana continental shelf (LCS) to better understand the linkages between
water column metabolism and the formation ofhypoxia (dissolved oxygen <2 ml O2-1) in the region. Water column
community respiration rates (WR) were measured on 10 cruises during spring, summer and fall seasons from 2003
to 2007 at multiple sites distributed across the Louisiana continental shelf, overlapping the region where bottom-
water hypoxia occurs. We found consistent broad scale patterns in WR rates that followed depth and salinity
gradients across the shelf. Observed WR rates were highest at low salinity inner shelf stations (<30 m depth) and
deer eased with increasing water depth. Surface waters had higher WR rates than bottom waters, a pattern most
pronounced near the Mississippi river during spring and early summer. Surface water WR rates were highest in
eastern transects and decreased westward; a trend that was not evident in bottom waters. WR tended to be higher in
spring and summer compared to fall months, but overall the seasonal variability was small. We combined the WR
rate measurements with contemporaneous measurements ofphytoplankton productivity rates (reported in Lehrter et
al, 2009, Continental Shelf Research, 29: 1861-1872) to estimate net water column metabolism. There was
consistent evidence of net heterotrophy, particularly in western transects, and in deeper waters (440 m depth),
indicating a net organic carbon deficit on the LCS. We offer a simple scale argument to suggest that riverine and
inshore coastal waters may be significant sources of organic carbon to account for this deficit. This study provided
unprecedented, continental shelf scale coverage of heterotrophic metabolism, which is useful for constraining
models of oxygen, carbon, and nutrient dynamics along the LCS.
Rabalais N. N., R. E. Turner, B. K. Sen Gupta, D. F. Boesch, P. Chapman, and M. C. Murrell
(2007). Hypoxia in the northern Gulf of Mexico: Does the science support the plan to
reduce, mitigate, and control hypoxia? Estuaries and Coasts 30:753-772.
We update and reevaluate the scientific information on the distribution, history, and causes of continental shelf
hypoxia that supports the 2001 Action Plan for Reducing, Mitigating, and Controlling Hypoxia in the Northern Gulf
of Mexico (Mississippi River/Gulf of Mexico Watershed Nutrient Task Force 2001), incorporating data,
publications, and research results produced since the 1999 integrated assessment. The metric of mid-summer
hypoxic area on the Louisiana-Texas shelf is an adequate and suitable measure for continued efforts to reduce
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nutrients loads from the Mississippi River and hypoxia in the northern Gulf of Mexico as outlined in the Action
Plan. More frequent measurements of simple metrics (e.g., area and volume) from late spring through late summer
would ensure that the metric s representative of the system in any given year and useful in a public discourse of
conditions and causes. The long-term data on hypoxia, sources of nutrients, associated biological parameters, and
paleoindicators continue to verify and strengthen the relationship between the nitratenitrogen load of the
Mississippi River, the extent of hypoxia, and changes in the coastal ecosystem (eutrophication and worsening
hypoxia). Multiple lines of evidence, some of them representing independent data sources, are consistent with the
big picture pattern of increased eutrophication as a result of long-term nutrient increases that result in excess
carbon production and accumulation and, ultimately, bottom water hypoxia. The additional findings arising since
1999 strengthen the science supporting the Action Plan that focuses on reducing nutrient loads, primarily nitrogen,
through multiple actions to reduce the size of the hypoxic zone in the northern Gulf of Mexico.
Schaeffer B. A., G. A. Sinclare, J. C. Lehrter, M. C. Murrell, J. C. Kurtz, R. W. Gould, Jr.
(2011). Spatial and temporal characteristics of light attenuation in the northern Gulf of
Mexico hypoxic zone. Remote Sensing of Environment. doi:10.1016/j.rse.2011.09.01
The Sea-viewing Wide Field-of-View Sensor (SeaWiFS) derived diffuse light attenuation along the Louisiana
continental shelf (LCS) was examined at monthly scales from 1998 to 2007 to characterize temporal and spatial
patterns, and responsible physical forcing conditions. The Sea WiFS diffuse light attenuation ranged from 0.10 to
2.64 nT1. Stepwise multiple linear regression analysis suggested that spatial and temporal patterns in diffuse light
attenuation were influenced by wind speed, nutrient loading, and river discharge from the Mississippi and
Atchafalaya River Basin. SeaWiFS daily integrated surface photo synthetically active radiation (PAR, 400-700 nm)
and diffuse light attenuation were used to calculate the absolute PAR and percentage of surface PAR that reached
the sediment water interface (SWI) on the LCS. Large portions of the LCS were euphotic to the SWI especially
during April and May. This finding implied that significant primary production was possible beneath the pycnocline
during spring and early summer. In addition, this study was the first to demonstrate that the euphotic depth was
correlated to the depth at which the water column turned hypoxic on the LCS. The development of hypoxic waters
may be influenced by decreased light availability below the pycnocline in addition to aforementioned physical
forcing.
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EPA/600/R-13/257 | September 2013 | www.epa.gov/ged
United States
Environmental Protection
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$300
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