United States	Corvallis Environmental
Environmental Protection	Research Laboratory
Agency	Corvallis, Oregon 97330
PRODUCTION IN COASTAL SALT MARSHES
OF SOUTHERN CALIFORNIA
H. Peter Eilers*
Department of Geography
California State University
Fullerton, California 92634

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PRODUCTION IN COASTAL SALT MARSHES
OF SOUTHERN CALIFORNIA
H. Peter Eilers*
Department of Geography
California State University
Fullerton, California 92634
~Current address:
U.S. Environmental Protection Agency
'200 SW 35th Street
Corvallis, Oregon 97330

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PRODUCTION IN COASTAL SALT MARSHES
OF SOUTHERN CALIFORNIA
by
H. Peter £ilers
Department of Geography
California State University
Fullerton, California 92634
Grant No. R805438-01-1
Project Officer
Harold V. Kibby
Environmental Research Laboratory
U.S., Environmental Protection Agency
Corvallis, Oregon 97330
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330

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DISCLAIMER
This report has been reviewed by the Corvallis Environmental Research
Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Approval does not signify that the contents necessarily reflect
the views and policies of the U.S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
ii

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ABSTRACT
Production ecology in southern California coastal
salt marshes was investigated by harvesting macrophytes
and monitoring environmental factors (substrate salinity,
pH, nitrogen, redox, water content, temperature, and tide
level) at four locations—Sweetwater River Estuary, Los
Penasquitos Lagoon, Upper Newport Bay, and Bolsa Bay—over
an annual cycle beginning fall 1977. Net aerial primary
production estimates computed by summing production in
individual species and adjusting for interval death and
shedding and disappearance of dead material averaged 3196,
3787, 2150, and 2494 g m-2yr_1 for study sites, and were
1.3 to 1.7 times greater than estimates computed by the
method of Smalley (1959). Instantaneous rates of dis-
appearance for dead material based on litter bag sets
ranged from 2.2 to 2.7 mg g-1 day-1 and were lowest at Los
Penasquitos Lagoon. Production levels were highest on
creek levees and transition to upland and lowest in back
levee depressions, fore levee slopes, and pans—suggesting
that habitat, especially drainage and salinity, exerts
greater control over macrophyte production in the marsh
than does tide level alone. High levels of production in
Salicornia virqinica and Frankenia qrandiflora at Los
Penasquitos Lagoon suggests that production in some plant
species may be increased by reduced tidal contact.
i i i

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TABLE OF CONTENTS
Abstract 				iii
Figures		viii
Tables 	 ....... 	 x
Acknowledgements		 			xii
INTRODUCTION 				1
Purpose and Scope					1
Salt Marshes and Production			1
Salt Marshes of Southern California . 		2
CONCLUSIONS							4
METHODS 		5
Study Areas ...... 	 			5
Sweetwater River Estuary . 	 		5
Los Penasquitos Lagoon 	 		7
Upper Newport Bay . 			 . . 				9
Bolsa Bay			9
Sampling Procedures—Vegetation		 . . 	12
Transect location and sample macroplots . . 			12
Vegetation sampling and treatment of samples 		13
Disappearance of dead material 			14
Calculation of above-ground net primary production ......	14
Sampling Procedures--Substrate 		15
Salinity 		 .....	15
Reaction, redox, ammonia 		15
Water content						15
Temperature			16
Elevation . . . 					 . .	16
Tidal Inundation			16
Habitat Types 		 		16
Data Analysis			17
v

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RESULTS		.. .		18
Vegetation . 				..	18
Plant species . .				18
Biomass 		 		18
Disappearance of dead material .;		 			20
Net Production of Stands . 			20
Net Production of Species ........ 			24
Substrate 						26
Salinity					26
Reaction .......... 	 			26
Ammonia							29
Redox 				29
Water content 			29
Temperature		 				33
Elevation				33
Habi tat Type 			33
Fore: Levee Slope ..... 	 . 		36
Levee Crest . 			36
Back Levee Slope ............ 	 ....	36
Back Levee Depression 				36
Slope Below Upland 					 . . .	39
Upland Transition 					39
Pan . . ; 				39
Net Production and Environment		 . 		39
Stand net producti on and el evati on 				39
Species net production, elevation and plant communities ....	39
Stand net production and habitat type		42
Species net production and habitat type . 				44
Explanatory models: net production and environment 		44
DISCUSSION 	 ........	50
Disappearance of Dead Material		50
Net Production . 		50
Role of tidal fluctuation 					50
Elevation versus habitat . 			 . . 		52
Comparision with other salt marshes and latitudinal trends . .	53
The Spartina Question		55
Effects of Long Term Removal of Tidal Access--Bolsa Bay ...... 56
vi

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LITERATURE CITED
58
APPENDICES 				64
A. Macroplot, living and dead standing crop biomass			64
8. Net production for plant species by macroplot ......... 67
C.	Substrate measurements ........ 	 	 . 70
1.	Salinity of substrate at 0 to 5 cm
2.	Salinity of substrate at 45 to 50 cm
3.	Salinity of substrate free-water
4.	Reaction (pH) of substrate free-water
5.	Ammonia in substrate free-water
6.	Redox potential of substrate free-water
7.	Water content of substrate at 0 to 5 cm
8.	Water content of substrate at 45-50 cm
9.	Temperature of substrate at 0 to 5 cm
10.	Temperature of substrate at 45 to 50 cm
D.	Macroplot elevation and habitat type 	 ..... 88
vi i

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FIGURES
Figure	Page
1.	Southern California salt marshes. Asterisk denotes seasonally
closed ocean inlet. North is toward top of the figure 	 3
2.	Sweetwater River Estuary. Square pattern denotes salt marsh;
dashed lines represent diked and degraded marsh. Paradise
marsh at left drains to Sweetwater marsh through a recently
excavated channel. E Street-Vener pond marsh is at right
center, G Street marsh at right. Arrows from top show position
of transects B, A, and C		 6
3.	Los Penasquitos Lagoon. Square pattern denotes general extent
of salt marsh. Marsh above and to the right of Atecheson,
Topeka and Santa Fe tracks is partially degraded with low
vegetation density and contains some brackish marsh. Arrows
clockwise from top show position of transects D, C, B, and A. . . . 8
4.	Upper Newport Bay. Square pattern represents salt marsh, and
arrows from left show- location of transects B and A on Shell-
maker Island, and C on Middle Island. PCH is Pacific Coast
Highway. Incised area above "Upper" is housing development on
former marsh investigated by Stevenson (1954) 			10
5.	Bolsa- Bay. North-south dike separates Inner from Outer Bolsa.
Dashed lines denote degraded salt marsh contained largely
within land owned by Signal Oil Company. Square pattern is
salt marsh within Bolsa Chica Ecological Reserve. PCH is
Pacific Coast Highway 	 11
6.	Living and dead standing crop biomass means ± S.E. (g nr2)
through the sample period for study areas. Solid line denotes
living biomass, dashed line is dead biomass 	 21
7.	Mean interstitial salinity (ppt) of substrate at 0-5 cm depth
(solid, line) and 45-50 cm (dashed line) ± S.E. for study areas
through the sample period 	 27
8.	Mean pH of substrate soil free-water ± S.E. for study areas
through the sample period		28
9.	Mean ammonia (10-SM) of substrate free-water ± S.E. for study
areas through the sample period	30
viii

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10.	Mean redox potential (Eh-mV) of substrate free-water ± S.E. for
study areas through the-sample period		 . 	31
11.	Mean water content (%-<- of moist weight) of substrate at 0-5 cm
(solid: line) and 45-50 cm (dashed line) ± S.E. for study areas
through the sample period 			32
12.	Mean temperature (°C) of substrate at 0-5 cm (solid line) and
45-50 cm (dashed Tine) ± S.E. for study areas through the
sample period-			 34
13.	Vertical range of salt marsh in four southern California
locations. SRE is Sweetwater River Estuary, L£L is Los
Penasquitos Lagoon, UNB is Upper Newport Bay, BB is Inner
Solsa Bay, BB is Outer Bosla Bay. Elevation in meters
referenced to local mean higher water 	 	 35
14.	Location of habitat types along a hypothetical marsh profile.
Habitats- from left are Fore Levee Slope, Levee Crest, Back
Levee Slope, Back Levee Depression, Slope Below Upland, Upland
Transition, and Pan . 				37
15.	Macroplot net production and elevation. Production is SSTC in
g m-^yr-1; elevation (m) referenced to local mean high water. ... 40
16.	Elevational range of plant species in macroplot samples. Peak
corresponds to elevation of maximum^ production. Elevation (m)
referenced to local mean high water	41
17.	Mean net production (g. n^yr-1, SSTC) by habitat type	43
ix

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TABLES
Table	Page
1.	Transect length and number of sample macroplots 		13
2.	Harvest dates 1977-1978 	 ....	13
3.	Species frequency in quadrant samples 		19
4.	Species diversity of macroplot samples 		20
5.	Disappearance rates for dead material computed from dry weight
of litter bag contents. Litter bag sets placed as follows:
SRE, 10/22/77, LPL, 10/28/77; UN8, 11/11/77; BB, 11/11/77 	 22
6.	Annual net production estimates based on three methods of com-
putationi ST is method of Smalley (1959); SST is sum of
individual species production based on Smalley (1959); SSTC is
SST corrected for disappearance of dead material	23
7.	Ratios of production estimates derived by the Smalley method
(ST) to the sum of individual species production (SST) and sum
of individual species production corrected for interval decom-
position (SSTC) 			24
8.	Summary of net production for plant species	25
9.	Mean elevation, number of species, and substrate conditions for
habitat types				38
10.	Mean species net production for habitat types .. 	 45
11.	Pearson correlation coefficients for net production with eleva-
tion, number of species and substrate variables 		 46
12.	Summary of stepwise multiple regression—net production with
elevation; number of species.; root zone salinity, water
content, and temperature; and soil free water ammonia, redox
and pH. ...... 			47
13.	Summary of stepwise multiple regression—net production (SSTC)
with elevation; root zone salinity and water content and soil
ammonia redox and pH.-	"			49
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14.	Disappearance rate- of dead material in salt marshes along the
Atlantic and. Gulf Coasts of North America compared to those in
southern California (mg g-1day-1). The range of values
contains, means, for plant species sampled. . . . 		
15.	Net production for salt marshes along the Pacific Coast of
North America (g m-2yr-1)		
xi

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ACKNOWLEDGEMENTS
I thank Kathleen Kunz, Michael Sweesy, and Inda Taylor for field and
laboratory assistance; their persistence and dedication is appreciated. I
also thank Jim Lamprecht for assistance in computer programming and stat-
istical analysis; Christopher Lee for help with tide level recording; Preston
Johns, Ron Hein, and Dan Frazer of the California Department of Fish and Game
for facilitating the study of Upper Newport Bay and Bolsa Bay by providing
aerial photographs and advice; and Russ Belmer and Russ Iketa of the Los
Angeles District Corps of Engineers for aerial photographs, reports, and
elevational data. Most of all, I am grateful to Harold Kibby and the Environ-
mental Protection Agency for making this study possible—and to Kay, Brandt,
and Anna Eilers for support, encouragement,, and time to complete the work.
xi i

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INTRODUCTION
Purpose and Scope
This study was designed to answer four questions about macrophyte
production in coastal salt marshes of southern California: a) what levels of
production are achieved by plant species and plant communities; b) to what
extent does production vary within and between marshes especially those with
and without regular tidal inundation; c) what physical factors control or best
explain variations in production; and d) how does production in southern
California salt marshes compare with that at other latitudes on the Pacific
Coast and at similar latitudes on the Atlantic Coast?
Salt Marshes and Production
A growing, literature suggests that coastal salt marshes are among the
most productive of natural systems (Teal 1962, Cooper 1974, Clark 1974,
Chapman 1976, Turner 1976). Salt marshes occupy a fortunate position between
the limits of tidal inundation. Essential nutrients entrained by terrestrial
runoff are transported, along with nutrients from coastal waters to marsh soils
by tidal flux (Steever et aL 1976). While primary production in the marsh is
high, marked variations in yield occur. Explanations for intramarsh
variations in production, and species distribution as well, have involved
factors related to tides; such as, frequency and duration of tidal inudation
(Mahall 1974, Eilers 1975, Mahal! and Park 1976c), tidal range (Steever et al.
1976), waterlogging (Brereton 1971), drainage density and proximity to creek
channels (Smalley 1959, Eilers 1975), and soil salinity (Adams 1963, Good
1972, Mahall and Park 1976b). Several authors (Tyler 1967, Valiela and Teal
1974, Patrick and Delaune 1976) have demonstrated the importance of soil
nitrogen (especially ammonia) to the level of production, and others (Adams
1963, Tyler 1971) have shown that species occurrence as well as yield may be
related to the abundance of soil iron.
Production by salt marsh autotrophs is onlypartially consumed by i_n situ
herbivory (Smalley 1959, Teal 1962). Much of the remaining dead leaves andi
stems of marsh macrophytes are acted upon by bacteria and. transported from the
marsh by tides as energy and nutrient-rich organic detritus (Odum and de la
Cruz 1967). This material becomes an important food source for estuarine
consumers, expecially filter feeders, and thereby aids in the maintenance of
the high level of secondary production characteristic of coastal ecosystems.
Export of particulate detritus is greatest for intertidal elevations in the
marsh and decreases with declining inundation frequency (de la Cruz 1973,
Eilers 1975, Heinle and Flemer 1976). In situ decomposition in the high marsh
is likely to be more complete due to the rarity of tidal inundation and,
1

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therefore, export materials from more elevated positions take the form of
soluble organics and nutrient ions which are carried seaward by rainfall and
extreme high tides.
Knowledge of marsh production in North American and its influence on
general coastal productivity rests almost totally on investigations conducted
along the Atlantic and Gulf Coasts. While much of the value placed on Eastern
marshes has been applied to those of the West Coast by such agencies as the
California Coastal Zone Conservation Commission (CCZCC 1975) and the San
Francisco Bay Conservation and Development Commission (SFBCDC 1969), the
productivity of Pacific marshes, especially those along the California coast,
has yet to be fully demonstrated. Turner (1976) compared production values
for salt marshes along the- Atlantic Coast and found a marked increase in yield
with decreasing latitude. If this trend is present on the Pacific Coast,, high
yields, and perhaps high detrital export, may be expected to characterize
southern California coastal marshes.
Salt Marshes of Southern California
Of the 229 km2 of coastal salt marsh in California, approximately 10
percent occurs in the southern coastal counties of Santa Barbara, Ventura, Los
Angeles, and San Diego (Speth 1970). Marshes occur in bays and lagoons
(Figure 1) and may generally be considered in two groups—those in continuous
contact with the ocean and those with seasonal or occasional contact (Purer
1942, Macdonald 1977). The former are subjected to regular tidal inundation;
the latter are closed off by down-coast movement of beach sand except during
periods of abnormally high tide or high terrestrial runoff—both of which are
most common in the winter. Diked marsh, formerly open to tidal inundation but
now removed from tidal influence., comprises a third group.
Southern California coastal marshes have been recognized as important
nesting and feeding areas for migratory birds (Frey et, al. 1970, U.S. Depart-
ment on Interior 1972, Speth et aL 1976), and it lT likely that energy
export, expecially from open marshes/ is important to coastal .fisheries
resources. However, most southern California marshes are threatened by urban
development. Indeed, many marshes have been reduced in area or completely
destroyed by encroaching urbanism. For example, Los Angeles County once
contained 2720 ha of salt marsh located mostly at Ballona Creek. At present,
only 32 ha of degraded marsh remain at Ballona Creek as a result of marina
construction and creek channelization (Darby 1964, Speth 1970). Mission Bay
in San Diego County has suffered a similar loss of marsh; 8.4 ha remain of the
nearly 960 ha once found there.
2

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PT.
CONCEPTION
SANTA BAR8ARA
.Goleta Slough
Carpenterla Marsh
Ventura River*
LOS ANGELES
Mugu Lagoon
Malibu Lagoon*
Ballona Creek
Anaheim Bay
Solsa Bay
Upper Newport Bay'"'
San Mateo Creek*
PACIFIC
OCEAN
Santa Margarita Riv.*—\
San Luis Rey River* —)
8uena Vista Lagoon*'
Aqua Hedionda Lagoon-
8atiquitos Lagoon*
San Oieguito Lagoon-
Los Penasquitos Lag.-
Mission 8ay'
OCEANS IOE
SAN 01 EGO
San D iego. Bay '
Tiajuana River —
MEXICO
Figure 1. Southern California salt marshes. Asterisk denotes seasonally
closed ocean inlet. North is toward top of the figure.
3

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CONCLUSIONS
The following conclusions may be drawn from this investigation.
1.	Estimates of net aerial primary production computed as the sum of
individual species production with accounting for interval death and
shedding and disappearance of dead material are higher than those
computed by the traditional approach of Smalley (1959), are better
suited to polyspecific stands than those of Smalley (1959) and
Wiegert and Evans (1964), and are felt to be close to true net
aerial primary production after herbivory.
2.	Macrophyte production varies within and between southern California
salt marshes.
3.	Macrophyte production, especially in Salicornia virginica and
Frankenia grandiflora, may be increased by reduced tidal contact.
4.	Habitat, especially drainage and salinity, exerts greater control
over macrophyte production in the marsh than does tide level alone.
5.	Production estimates from this study, together with those of Eilers
(1979), support an increase in salt marsh production with-decreasing
latitude.
6.	Production levels in southern California salt marshes are equal to
or greater than those of salt marshes at the same latitude on the
Atlantic Coast.
7.	Future investigations of salt marsh production should be coordinated
by a similar method to facilitate comparison of results and
recognition of trends.
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METHODS
Study Areas
Four study areas were, selected to represent the variety and latitudinal
extent of coastal salt marshes in southern California.
Sweetwater River Estuary (SRE)
The Sweetwater River drains 570 km2 of the Peninsular Range of San Diego
County. From its. headwater area near Stonewall Peak (el. 1747 m) the river
flows westward through Loveland and Sweetwater Reservoirs to the eastern edge
of San Diego Bay, 10 km north of the Mexican border, between the cities of
Chula Vista and National City.
Salt marsh occupies estuarine deltaic deposits at the mouth of the river
(Figure 2), and is floristically diverse with a predominance of mixed stands
but Spartina foliosa occurs in pure stands along the Sweetwater River channel
and locally Frankenia grandiflora, Batis martima and Salicornia virginica form
monospecific, stands. The present marsh is much reduced from its former
extent. Prior to the initiation of dredge spoil deposition on the marsh (the
D Street fill) in 1947, 232 ha of salt and brackish marsh were present. By
1977, total marshland had declined to 83 ha and fragmented.into three units:
Sweetwater marsh (42 ha), Paradise marsh (23 ha), and E Street-Vener Pond
marsh (18 ha).
The Paradise marsh, in addition to being partially filled, has been
degraded by off-road vehicle use; diking has reduced tidal access in the E
Street-Vener Pond marsh. Even though the dredge deposits exacted heavy toll
on viable marsh and forced realignment of the main channel of the Sweetwater
River, the surviving Sweetwater marsh is otherwise intact. Mudie (1970a)
considered it to be the highest quality marsh area remaining within San Diego
Bay. For this reason, and because of its estuarine setting with perennial
tidal contact, the Sweetwater marsh was selected as a primary study site.
Previous work concerning the Sweetwater marsh is limited primarily to
several ecological inventories compiled by or for government agencies (Earth
Sciences Associates 1971, Mudie 1970a, Mudie 1970b, Ford et aL 1971, San
Diego Unified Port District 1972, Browning and Speth 1973) and to the assess-
ment of environmental impact by proposed flood control of the Sweetwater River
(U.S. Army Corps of Engineers 1976). In a classic study of San Diego County
marshes, Purer (1942) referred briefly to floristic composition at Sweetwater
and' included this marsh in a group with marsh at the south end of the Bay and
at the mouth of Otay River for the presentation of monthly soil and water
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NATIONAL CITY
CHULA VISTA

SOME RR
INTERSTATE 5
AT&SF RR
STREET
FILL
lkm
SAN DIEGO BAY
Fig. 2. Sweetwater River Estuary. Square pattern denotes salt marsh; dashed lines represent
diked and degraded marsh. Paradise marsh at left drains, to Sweetwater marsh through
a recently excavated channel. E Street-Vener pond marsh is at right center, G Street
marsh at right. Arrows from top show position of transects B,, A, and C.

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salinity measurements. However, Purer (1942) does not specify the Sweetwater
Marsh as her sampling site within the group.
Ownership of the Sweetwater marsh is divided between the California
Department of Transporation and Santa Fe Land Improvement Co. Vener Farms,
Inc. cultivate tomatoes directly to the south. The D Street fill to the north
is held by the San Diego Unified. Port. District.
Los Penasquitos Lagoon (LPL)
Located on the northern city limits of San Diego and 42 km north of
Sweetwater, Los Penasquitos Lagoon is the seaward terminus of SoleildU diui
Carmel Valleys (Figure 3). The lagoon name is after a creek in the upper
drainage basin, although reference to the wetland as Torrey Pines Lagoon after
its proximity to Torrey Pines State Reserve is also seen.
The outstanding characteristics of Los- Penasquitos Lagoon are a
depauperate flora and limited tidal access. Vigorous Salicornia virginica
dominates the marsh in extensive pure stands. Frankenia- -gyandif^ora and
Distich!is spicata occur locally. Even though the lagoon contains 156 ha of
wetland (95- ha of salt marsh) and numerous well-defined tidal channels, some
with depth to 9 m, sufficient tidal prism to maintain a perennial breech in
the coastal strand is lacking. Only in the winter months when heavy-Wefter'STrecT
runoff combines.with seasonal beach erosion does the tide penetrate the marsh.
Summer runoff, when it occurs, may be simply impounded and gradually lost by
seepage and7evaporation.
Mudie et al. (1974) presented evidence of continuous ocean contact at
least until 1888. A combination of railroad and highway construction after
this date helped create present conditions by disruption of the drainage,
system and constriction of the seaward channel. From 1965 to 1970 two sewage
treatment facilities discharged secondary overflow into the lagoon. While
this added flow helped to maintain more or less permanent ocean access during
the period, nutrient enrichment led to the production of thick algae mats and
high biological oxygen demand. With the loss, of this added, flow in 1970, and
despite efforts to maintain ocean access (Inman and Nordstrom 1978), contact
with the ocean continues to be seasonal.
Los Penasquitos Lagoon was selected as a primary study site because, even
with these human modifications, it remains the least altered of lagoons in
southern California and is an excellent representative of a wetland with
limited tidal control.
Previous study of Los Penasquitos Lagoon includes detailed ecological
descriptions (Bradshaw 1968, B.radshaw and Mudie 1972, Mudieet aH. 1974) and
investigation of physical characteristics (Carpelan 1969). Purer (1942)
included Los Penasquitos Lagoon (Soledad Station) among her 12 study sites.
Zedler and Mauriello (1979) have made preliminary comparison of salt marsh
production at Los Penasquitos Lagoon, Mission Bay and Tijuana River Estuary.
7

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TORREY PINES
STATE RESERVE
DEL MAR
lkm
PACIFIC
OCEAN
Fig. 3. Los Penasqultos Lagoon. Square pattern denotes general extent of salt marsh. Marsh
above and to the right of Atcheson Topeka and Santa Fe tracks is partially degraded
with low vegetation density and contains some brackish marsh. Arrows clockwise from
top show position of transects D, C, B, and A.

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Title to Los. Penasquitos Lagoon, including the salt marshes, is held by
the State of California. Most of the marsh area is classified as a preserve
and is under the jurisdiction of the State Department of Parks and Recreation.
Upper Newport Bay (UNB)
Newport Bay, 110 km north of Los Penasquitos Lagoon, is continuously open
to the Pacific Ocean. Two strikingly different subdivisions separated by the
Pacific Coast Highway (U.S. 101 Alt.) comprise the bay (Figure 4). Lower
Newport Bay" is.a busy small craft harbor with high density urban development
on the surrounding shore. Former salt marsh there has been^totally replaced
by slips and "structures. Upper Newport Bay, by contrast, is 44-ttle developed,
surroundedzby cliffs 10 to 30 m high (Newport Mesa), and, whi-le-some marsh has
been converted to dwellings, about 58 ha still remains. The"fiarsh vegetation
is floristica-lly diverse, but generally low in stature. Spartina foliosa is
important along, creek and pure stands of monanthocloe 1ittoralis occur at
highest levels.
Upper Newport Bay is an important avian nesting and feeding area.
Seventy species of birds are common to the bay and 89 others are occasional
visitors (Frey et al. 1970).
Although the Santa Ana River discharged into Lower Newport Bay for a t3me-
around 1900, and may have occupied the upper bay in the geological past
(Stevenson 1954), fresh water input to the upper bay is now from three low
volume sources—San Diego Creek, Delhi Channel, and Big Canyon Creek. Aside
from high nutrient loads, these sources transport great volumes of suspended
sediment during the winter from the rapidly urbanizing watershed. High
turbidity and rapid siltation of channels is of increasing concern (Stevenson
1978). Dredging of the main channel has been deemed necessary in the past and
some spoils have been deposited on salt marsh (primarily near the distal end
of Shellmaker Island).
Upper Newport. Bay was selected as a primary study site to represent salt
marsh in a bay setting with unrestricted tidal fluctuation. Its status as
ecological reserve, latitudinal position, and presence of large areas of
largely undisturbed salt marsh were also considerations.
Studies of salt marsh plant ecology in Upper Newport Bay are limited to
the work of Stevenson (1954), Stevenson and Emery (1958), and Vogl (1966).
Descriptive treatment.of the upper bay in general is provided by Frey et al/
(1970) and Stevenson (1978).
Bolsa Bay (BB)
Bolsa Bay, 16 km north of Newport Bay and about 800 ha in area, occupies
the seaward end of an alluvial-filied valley originally excavated at lower sea
level in the Bolsa Chica-Huntington Mesa of western Orange County (Figure 5).
Two subdivisions comprise the present bay. Outer Bolsa, directly to the west
of the Bolsa Chica Mesa, is tidally controlled through a narrow channel
9

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NEWPORT BEACH
BAY
NEWPORT MESA (NEWPORT
LOWER
NEWPOR
BAY
JAMBOREE
ROAD
1 km
Fig. 4. Upper Newport Bay. Square pattern represents salt marsh, arid arrows from left show
location of transects B and A on Shellmaker Island, and C on Middle Island. PCH is
Pacific Coast Highway. Incised area above "Upper" is housing development on former
marsh investigated by Stevenson (1954).

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HUNTINGTON
HARBOR
D inner bolsa."
pch
PACIFIC OCEAN
lkm
Fig. 5. Bolsa Bay. North-south dike separates Inner from Outer Bolsa. Dashed lines denote
degraded salt marsh contained largely within land owned tyy Signal Oil Company. Square
pattern is salt marsh within Bolsa Chica Ecological Reserve. PCH is Pacific Coast
Highway.

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leading to adjacent Sunset Bay. A dike emplaced in 1899 by a private hunting
club,, and containing, culverts with flap valves to prevent incursion of flood
tides, extends from the southern edge of the mesa to the beach and separates
•Outer from Inner Bolsa. Salt marsh in Inner Bolsa is
Spartina foliosa grows with low vigor on creek margins and Frankenia
grandiflora, Distich!is spicata, and Salicornia virginica occur with greater
vigor at higher elevations.
Oil Was discovered in Inner Bolsa. in 1926. Oil and gas exploitation
began in 1943" after extensive diking and well pad construction. The State1 of
California gained title to 140 ha of wetland (all of Outer Bolsa and part of
the area outsvde the drilling area in Inner Bolsa) in 1973 and established the
Bolsa Chica. Ecological Reserve under the jurisdiction of the Department of
Fish and Game. After 1973 plans were made to return tidal fluctuation to
State-held lands in Inner Bolsa (after dike construction around this port-ion
of the reserve, limited tidal fluctuation was returned after nearly 89 years
to Inner Bolsa in November 1978).
Inner Bolsa was included as a primary study site for several reasons:
Study of this.marsh before the return of the tides would provide some insight
into, the ecological effects^ of long-term tidal removal, follow-up studies
could be initiated to assess the impact of tidal restoration, and, most
important, Inner Bolsa is representative of highly disturbed salt marshes in
southern California (others are La Ballona Creek and Santa Ana River).
Several authors, provided description of Bolsa Bay natural resources
(Moffat and NichoT 1971, Speth et ah 1976, Henrickson 1976). Macdonald et
al., (19710 assessed plant succesTfon since removal of tidal fluctuation. The
most detailed treatment of the bay including, marsh ecology, however, is that
completed by Dillingham Environmental Co. (1971) for Signal Properties, the
major landowner. More recently, EDAW (1978) reviewed the work of Dillingham
(1971) and considered various development alternatives.
Sampling Procedures—Vegetation
Transect location and sample macroplots
With the aid of aerial photography, a system of transects was located in
each study marsh. Each transect was so located as to include as much variety
in vegetation pattern and habitat as possible. Semi-permanent wood stakes-
were driven into the marsh at intervals along transects to ,serve as recovery
points for sampling macroplots. Distance between macroplots was adjusted to
maximize representation of pattern and habitat, and, in some cases, avoid
creek channels. The position of the 11 transects containing 82 sample
macroplots is shown in Figures 2 through 5. Transect length and number of
macroplots along transects varied within and between study marshes (Table 1).
12

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Table 1. Transect Length and Number of Sample-Macroplots.



No. of
Marsh
Marsh
Transect
Length (m)
Macroplots
Total
SRE
A
132
14


B
56
4


C
200
13
31
LPL
A
116
8


B
13
3


C
123'
7


D.
60
3
21
UNB
A
45.
6


B
70
7


C
266
12
35
BB
A
30
5
5
Total
11
—
--
82
Vegetation sampling and treatment of samples
Sample macrop lots were rectangular, 2.0 x 2.5 m, with the center of the
short Teg adjacent to the wood stake and the long axis perpendicular to the
right side of the transect (when looking seaward). Vegetation samples were
taken at intervals of six to eight weeks for one year beginning October 1977
(Table 2). All above-ground, vascular plant material (living and dead) was
harvested from within a 20 x 50 cm wire frame systematically located in the
macroplot. Each sample was collected from a different position in the maicro-
plot, and care was taken not to disturb future samples by progressively
sampling deeper into the plot and by allowing a buffer of at least 50 cm
between harvests.
Table 2. Harvest Date 1977-1978

Session
SRE
LPL
UNB
BB
1
Oct.
14-22
Oct.
22-28
Oct.
29-Nov. 11
Nov.
11
2
Dec.
9-10
Dec.
16-17
Jan.
3-7
Jan.
7
3
Feb.
11
Feb.
17-18
Feb.
24-25
Feb.
25
4
Apri 1
14-15
Apri 1
21
April
21-22
Apri 1
28
5
June
7-8
June
12
June
14
June
15
6
July
17
July
18
July
19
July
19
7
Aug.
23
Aug.
23
Aug.
23
Aug.
23
13

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Plant material constituting each sample was placed in an opaque plastic
bag, sealed with a short length of twisted wire, and refrigerated as soon as
possible- to minimize fermentation (Milner and Hughes 1968). In the labora-
tory, samples were sorted into green, attached dead, and dead of each species
with a separate miscellaneous litter component of unsortable dead material.
Each fraction was dried, in a gravity convection oven (Thelco model 17) at 85°C
to constant weight and then weighed on a?balance sensitive to .01 g.
Disappearance of dead material
The rate at which dead material disappears from the marsh was estimated
by using, a variation of the standard litter bag technique (Wiegert and Evans
1964). At the time of the first harvest, a number of macroplots in each study
marsh wais selected to represent overall diversity of sites, and a mix of plant
material approximating the species composition from each selected plot was
divided into four plastic screen bags of 1 mm mesh. Litter bags were secured
along the edges with staples and cloth tape after the contents of each had
been weighed and an aluminum identification tag placed within. A sub-sample
of plant material from each set was retained to establish proportionate dry
weight at the initiation of the experiment. The bags, containing. 50 to 200 g
of plant material and measuring 12 x 24 cm, were placed on bare soil in the
respective macroplots and kept, in place by stout monofilament line fastened to
pegs driven into the soil.
At intervals of approximately three months, one bag from each original
group of fbur was removed and its contents, freed from soil and new growth,
dried to constant weight. If it appeared that inorganic accumulations were
present (as was common for bags from macroplots near mudflats) the contents
were combusted in a muffle furnace, and the ash-free dry weight was
substituted for the-dry weight obtained above.
Disappearance rate of dead material was calculated as
r = [(dwt - dwt.) t dwt ] r (t.-t )
o	i	o	i o
where r = disappearance rate in g-g'day, dwt is dry weight at time zero, dwt.
is dry weight at the end of the interval, ana (t.-tQ) is the interval in days.
Calculation of above-ground net primary production
Estimates of net aerial primary production (NAPP) were computed by three
methods. Initially, the procedure of Smalley (1959) was followed whereby net
production for intervals between harvests Was computed with reference to
changes in live and dead biomass, then interval net production was summed over
the annual cycle (ST).
Because this application of the Smalley (1959) method does not account
for variations in biomass of individual species which may be out of phase with
total site biomass (Eilers 1975), a second estimate of annual production was
computed (SST). In this case changes in individual species living and dead
14

-------
biomass were used with the Smalley (1959) approach to yield species annual
production. Annual production for component species was then summed and
adjusted for changes in miscellaneous litter (positive changes in miscel-
laneous litter were added according to changes in total live biomass after
Smalley 1959).
The final approach (SSTC) to NAPP was a combination of the method of
Smalley (1959) and Wiegert and Evans (1964). Here the summation of individual
species net annual production (with accounting for miscellaneous litter) was
computed as above (SST), then the average disappearance rate for the marsh in
question was applied to interval changes in individual species and miscel-
laneous dead biomass and appropriate losses added.
Sampling Procedures—Substrate
At the time of each vegetation sample harvest, a suite of substrate
measurements was taken from each macroplot;
Sali nfty
Three aspects of substrate salinity were determined after a core sample
50. cm deep and 4 cm in diameter was extracted with a suction device. The
upper and lower 5 cm sections were cut from the core, and sub-samples of each
were individually wrapped in filter paper (Whatman No. 1), placed in a
separate plastic syringe, and squeezed to force out drops of interstitial soil
water for which salt content was determined with a Goldberg refractometer
(Behrens 1965). As soil free-water percolated into the hole from which the
core had been removed, samples were withdrawn by pipette and tested for
salinity with the same instrument.
Reaction, redox, ammonia
Soil free-water, as obtained above, was further subdivided and subjected
to three additional tests using a specific ion meter (Orion model 407a).
Reaction (pH) was determined directly with a combination electrode.
Oxidation-reduction potential (Redox) was measured directly with a combination
platinum electrode and converted to Eh (Orion 1978). Analysis for NH3-N by an
ammonia electrode followed the adjustment of sample pH to 11 by addition of
sodium hydroxide (Banwart et al. 1972).
Water content
After sub-samples of the upper and lower 5 cm of the extracted soil core
were taken for measurement of interstitial salinity, the remainder of. each was
sealed in a plastic bag. In the laboratory, after initial weighing, samples
were oven dried to constant weight, re-weighed, and percent water content (c)
computed, as, c = [(w-d) -r w] • 100, where w is sample weight wet and d is
sample weight dry.
15

-------
Temperature
Substrate temperature was measured at 5 cm and 50 cm depths with a
long-stem dial head thermometer (Reotemp) placed near harvested quadrats.
Elevati on
Elevation at each of 82 macroplots was determined with transit and stadia
(Pugh 1975). At Sweetwater and Bolsa, levels were double run to nearby tidal
bench marks (National City, R. 57 1926 and Los. Patos, 3; respectively).
No tidal bench marks were found near Los Penasquitos, but numerous
positions in the marsh had been surveyed: to National Geodetic Vertical Datum
(NGVD) and monumented by the U.S. Army Corps of Engineers. Levels at Los
Penasquitos were double run to several of these monuments and then converted
to tide level by applying, a conversion factor midway between those published
by the National Ocean Survey (NOS) for Scripps Institution, La Jolla, and
Newport Bay Entrance (Corona Del Mar).
Leveling at Newport was facilitated by recent work of the NOS for the
Environmental Protection Agency (NOAA 1978). Here tide level monuments left
by this survey served in the-double run procedure. Maximum acceptable closing
error for all leveling was. set at 3 cm-.
Tidal Inundation
In-marsh tide level recordings were obtained for periods of six and four
weeks at Sweetwater and Newport, respectively, with a recording gauge (Leupold
Stevens Model 031). Inundation periods for increments of elevation were to be
computed for the two marshes, but because the required simultaneous and long
term recordings for nearby primary gauges could not be obtained from the NOS,
this aspect of the study cannot be reported.
Water levels at Los Penasquitos were recorded at each sampling period
from a stake driven into the mud of a marsh creek, but continuous recordings
there were not included in this study. After the return of tidal fluctuation
to Inner Bolsa Bay in 1978, tide levels there were monitored with a staff
gauge over one 48-hour period.
Habitat Types
In order to test the importance of location within marshes to NAPP, all
macroplots were placed in one of seven topographically determined habitat
types: 1) Fore Levee Slope, 2) Levee Crest, 3) Back Levee Slope, 4) Back
Levee Depression, 5) Slope Below Upland,. 6) Upland Transition, and 7) Pan.
16

-------
Data Analysis
Data analysis followed Snedecor and Cochran (1967). Descriptive stat-
istics were produced for all vegetation and environmental data, analysis of
variance provided a means to explore variation of NAPP within and between
study areas, and relations between variables were investigated through cor-
relation and-multiple regression analyses.
17

-------
RESULTS
Vegetation
Plant species
Fifteen vastular plant species were recorded in sample quadrats (Table
3). Salicornia virginica was most frequent followed by Frankenia grandiflora
and Batis maritima. Rare species included Cressa truxillensis found only at
Los Penasquitos, and Lotus scoparius and Cordylanthus martimus found only at
Newport. Species diversity (variety) was: greatest for Newport nearly as great
for Sweetwater, but low for both Los Penasquitos and Bolsa. Monospecific
stands comprised 28, percent of the macroplot samples (Table 4), and the mean
number of species .for the 82 macroplots was 4.4.
Biomass
Macroplot living and dead standing crop biomass for harvest sessions is
found in Appendix A. Macroplot LPL-15 recorded the living biomass high of
3915 g m-2 (session 1) but, while two macroplots located near creek channels
(LPL-13, BB-5) showed no living material for two or more sessions, all others
had living material all year. With the exception of UNB-17 and SRE-26, all
macroplots contained dead biomass throughout the year. Maximum dead biomass
for all sites was 4749 g m-? (SRE-8, session 6), and the annual mean for
living and dead material over all macroplots was 751 and. 797 g m-2, respect-
ively.
Twenty-eight percent of the macroplots recorded a single living biomass
peak, but most macroplots recorded two peaks (72%). Single peaks occurred
most often in the summer, while dual peaks were most common winter-summer and
summer-fall. No clear relationship between the number of different species,
site elevation and the presence of single or dual peaks was detected, but the
common occurrence of dual peaks suggested that the vegetation responds to
summer warmth and fall, winter, and spring precipitation.
For dead biomass in macroplots dual peaks were likewise most common (78%
of macroplots) with winter-summer most frequent. Dual peaks in dead biomass
tended to occur concomitant with dual peaks in live biomass.
Mean living and dead biomass (Figure 6) reflected the persistence of dual
peaks in dead biomass but tended to mask dual living biomass peaks. Mean
living biomass minima occurred in March samples and greatest mean living
biomass was found in June samples for all marshes with the exception of Los
Penasquitos were the maximum was present in November 1977 (an August peak was
18

-------
Table 3. Species Frequency in Quadrat Samples.
Marsh
Total
Species
Batis maritima L.
Cressa~truxi1lensis HBK. var. val1icola
(Heller) Munz
Cuscuta salinia Engelm.
Djstichlis spicata (L.) Greene var.
spicata
Frankenia grandiflora Cham. & Schlect.
Jaumea carnosa (Less.) Gray
Limonium californicum (Boiss.) Heller
Lotus scoparius (Nutt.) Ottley spp.
scoparius
Monanthocloe 1ittoralis Englem.
Cordylanthus maritimus Nutt.
Salicornia bigelovii Torr.
Salicornia virginica L.
Spartina folipsa Trin.
Suaeda californica Wats.
Triglochin maritimum L. •
Number of Species
Abbr.
SRE(31)a
LPL(21)
UNB(25)
BB(5)
Freq(82)
Bama
23

19

42
Crtr

1


1
Cusa
4
2
2

8
Oi sp
11
1
13
3
28
Frgr
21
6
13
2
42
Jaca
11

13

24
Lica
16

11

27
Lose


1

1
Moli
8

6

14
Orpu


1

1
Sabi
14

10

24
Savi
28
20
19
3
70
Spfo
9

16
3
28
Suca
16

4

20
Trma
17

13

30

12
5
14
4
15
^ Total number of sample macroplots
Nomenclature after Munz (1974)

-------
Table 4. Species Diversity of Macroplot samples.
No. of
No. of
%.
No. of
No. of
%
Species
Macroplots

Species
Macroplots

1
23
28
6
6
1
2
10
12
7
11
14
3
4
5
8
5
6
4
6
7
9
6
7
5
7
9
10
3-
4
apparent in 1978). Relatively large standard errors for living and dead
biomass means, especially for Los Penasquitos and Bolsa, emphasized the
heterogeneity of vegetation along transects.
Disappearance of dead material
Dead plant material in most litter bag sets decomposed rapidly in the
first interval after placement in the marsh, then the rate of disappearance
declined (Table 5). This was expected because bags contained some recently
living plant parts, and leaching of organic matter is most rapid in the first
few days after death occurs (Odum et aL 1972). Site mean rates-ranged from
.67 to 3.74 mg g-1 day-1; a single bag recovered from BB-4 after 106 days
recorded the highest rate (9.43 mg g-1day-1), and the grand mean for LPL was
well below that for the other study marshes. The lower rate at LPL was
probably related to the woody Salicornia virginica placed in bags and dryness
resulting from infrequent tidal submergence.
Net Production of Stands
NAPP varied with the method of computation (Tables 6 and 7). The Smalley
(1959) method applied to changes in living and dead biomass without accounting
for growth in individual species (ST) provided estimates that were an average
of 1.44 times less than Smalley method applied to component species (SST) and
1.46 times less than SST corrected for decomposition of dead material between
sample intervals (SSTC). Thus the Smalley method as orignally applied
(Smalley 1959) appears to have severely underestimated NAPP, especially for
multispecies stands, and much better estimates were provided for all stands
when species growth patterns and litter decomposition were included. Yet,
while SSTC was considered the best estimate of the three computed for each
macroplot, values could be improved by accounting for losses to herbivory;
Production estimates (SSTC) ranged from 164 g nHyr-1 at BB-5 to 6369 g
m-2yr-i at LPL-9 with an overall mean for the four study marshes of 2986 g
m-2yr-i. Los Penasquitos Lagoon was clearly the most productive marsh; Upper
Newport Bay the least. Analysis of variance between marsh means showed that
differences in production were significant (P<.001).
20

-------
B
oO
¦w
£
O
1800 -

1600 -

1400 -
SRE
1200 -

1000 -

800 -
600 -
T
•
i.
|

0'
1
400 -
200 -

0 -

1800
£ 1600
1400
1200
1000
800
600
400
200
0
LPL
A
V
i/'K
—I	[—
N D
19 7 7
I
H
I	1—
A M
1978
~~r
A
1800 -
1600 "
1400 -
1200 -
1000 -
800
600-
400-
200-
0-
1800-1
e
00
S
o
H
S
£ 1600-
o
1400
1200-
1000-
800
600
400-
200-
0-
UNB
BB
r
0

-1	r~
N D
1977
~1
J
~r~
M
~T~-	1—
A M
1978
i
A
Figure 6. Living and dead standing crop biomass means ± S.E. (g in-2) through the sample period for study
areas. Solid line denotes living biomass, dashed line is dead biomass.

-------
Table5. Disappearance Rates for Dead Material Computed from Dry Weight
of Litter Bag contents. Litter Bag Sets Placed as Follows:
SRE, 10/22/77; LPL,. 10/28/77; UNB, .11/11/77; BB, 11/11/77.

Days in
Rate
Site x

Days
Marsh
Marsh
nig •g* day
mq-g-dav
Marsh
Marsh
SRE 1
113
3.45

UNB 1
106

306
.98


215

357
1.23
1.89

288
9
113
5.92


337

229
1.97

3
106

306
1.90


215

357
1.62
2.85

288
13
113
5.66


337

229
2.71

7
106

306:
2.25


2.5

357
2.10a
3.18

288
14
113
1.59 J


337

229
4.06




306
2.94*




357
2.27
2.27


15
113
.71

BB 2
106.

229
.26


145

357
1.04
.67

216
16
113
4.51


292

229
1.83

4
106

306
1.76




357
2.21 _
2.57




Grand x
2.38


LPL 4
113
2.57




301
.36




351
.26
1.06


13
113
2.83




228
1.62




301
1.83




351
2.02
2.08


15
228
2.37




301
2.17




351
1.47
2.00


20
113
1. 50




228
3.08*




301
1.58




351
1.89 _
2.18




Grand x
1.83


Rate
Site x
mg»g»day mg«g«day
2.26
1.40
1.15
1.07
6.42
3.07
2.67
2.79
4. 31
2.27!
2.26
2.14
Grand x
.4_43
3.50
1.06
1.58
9.43 _
Grand x
1.47
3.74
2.75
2.65
2.64
9.43.
2.64
(9.43)
* Computed from ash free dry weight
Two values were used at BB.
22

-------
Table 6. Annual Net Production Estimates (g m-Syr-1) Based on Three Methods
of Computation. ST is Method of Smalley (1959); SST is Sum of
Individual Species Production based on Smalley (1959); SSTC is SST
Corrected for Disappearance of Dead Material.
Marsh
ST
SST
SSTC
Marsh
ST
SST
SSTC
SRE 1
3256
3284'
3576
LPL 6
4990
5438
5710
2
993
1703
1769
7
2131
2131
2289
3
3517
5708
5824
8
3006
4396
4616
4
2361
3163
3321
9
2784
5778
6369
5
1918
3019
3135
10
2909
2909
3056
6
2447
3554
3723
11
5073
5073
5303
7
3484
4100
4220
12
2390
4615
5416
8
3800
5459
5573
13
1464
1464
1767
9
2280
3133
3243
14
2531
2531
2690
10
1410
2143
2232
15
5649
5649
5848
11
1750
2857
3048
16
2896
2896
3224
12
1633
2346
2412
17
1737
1737
2047
13
1869
3692
3789
18
4968
4968
5219
14
1614
1614
1824
19
2563
4431
4737
15
620
620
665
20
2264
2264
2417
16
491
1414
1430
21
1501
1501
1582
17
3691
5184
5402




18
2457
2457
2659
X
3084
3539
3787
19
5734
5734
6231
S.D.
1259
1448
1528
20
1318
3100
3192




21
1047
3016
3096




22
1376
4674
4768
UNB 1
1356
1556
1708
23
1531
2643
2718
2
1265
1648
1790
24
1702
3264
3355
3
1609
2461
2574
25
2355
3388
3429
4
1287
2154
2234
26
885
1770
1782
5
1040
2057
2292
27
1364
2993
3102
6
1215
1215
1339
28
1848
2979
3208
7
1187
1572
1687
29
1284
1289
1318
8
2540
4007
4104
30
2121
2479
2532
9
918
1819
1849
31
1349
2469
2492
10
1646
2390
2552




11
1331
1931
1847
X
2049
2943
3196
12
1371
2142
2263
S.D.
1117
1203
1330
13
2389
2389
2621




14
1214
2607
2691
LPL 1
4777
4777
5011
16
780
1125
1161
2
1924
1924
2088
17
1005
1354
1380
3
3137
3137
3155
18
1322
2289 ,
2331
4
2972
2972
3067
19
592
954
, 976
5
3113
3736
3922
20
1168
1224
1376
conti nued
23

-------
Table 6. (cont.)
Marsh
ST
SST
SSTC
Marsh
ST
SST
SSTC
UNB 21
1133
2321
2414
BB 1
4282
4380
4638
2 Z
895
1380
1393
2
T152
2214"
2372"
23
2906
2906
3217
3
205S
3522
3622
24
3432
3933
4055
4
1158
1561
1676
25
1722
1722
1969
5
164
164
164
X
1469
2035
2150
X
1762
2368
2494
S.D.
673
770
795
S.D.
1559
1652
1731




ALL x
2120
2833
2986




S.D.
1220
1339
1408
Table 7. Ratios of Production Estimates Derived by the Smalley Method (ST)
to Sum of Individual Species (SST) and Sum of Individual Species
Corrected for interval Decomposition (SSTC).

ST
SST
SSTC
SRE
T. 00
1.65
1.71
LPL
1.00
1.17
1.26
UNB
1.00
1.45
1.53
BB
1.00
1.49
1.35
ALL
1.00
1.44
1.46
Net Production of Species
Species net production estimates based on the Smalley (1959) method
corrected for interval decomposition (SSTC) are presented by macroplot in
Appendix B and summarized by marsh in Table 8. It may be found that summing
of component species production in macroplots yields a value less than total
SSTC for the site as presented above. The reason for this discrepency is that
harvested dead standing crop biomass often graded from parts recognizable as
to species to amorphous duff with no recognizable species affinity.
Accounting for this miscellaneous plant material, therefore, could not be
included in species estimates (this material was included in macroplot
estimates).
Overall, the most productive plant species were Frankenia grandiflora,
Salicornia virginica and Spartina foliosa. Qn an individual marsh basis,
these species were most important at Sweetwater but at Newport Frankenia was
conspicuously subdued, especially on transects A and B where it was all but
replaced by Monanthocloe littoral is. Sparti na was not present at Los
24

-------
Table 8. Summary of Net Production for Plant Species (g m-2yr-x)
Marsh
Species
X
Min.
Max.
Freq.
Marsh
Species
X
Min.
Max.
Freq.
SRE
Bamaa
264
6
980
23
UNB
Savi
634
10
3160
19

Cusa
72
2
238
4

Spfo
819
9
3217
16
(31 sites)
Disp
240
4
1426
11

Suca
120
10
142
4

Frgr
880
4
6231
21

Trma
204
20
511
13

Juca
442
1
2395
11







Lica
200
1
862
16
BB
Disp
901
74
1452
3

Mol i
232
43
562
8

Frgr
2318
72
4564
2

Sabi
231
1
713
14
(5 sites)
Savi
1035
459
1525
3

Savi
1176
22
3732
28

Spfo
486
164
1032
3

Spfo
611
3
2659
9






Suca
161
1
882
16







Trma
159
7
792
17






LPL
Crtr
127


2
All
Bama
221
5
980
42

Cusa
1


1
MARSHES
Coma
8


1
(21 sites)
Oisp
1184


1
TOGETHER
Crtr
127


2

Frgr
3274
1871
4864
6

Cusa
42
1
238
7

Savi
2789
1176
5848
20
(82 sites)
Disp
362
4
1561
28







Frgr
1046
4
6231
42







Juca
338
1
2395
24
UNB
Bama
168
5
620
19

Lica
203
1
862
27

Coma
8


10

Lose
5


1

Cusa
3
1
5
2

Moli
509
6
1351
14
(25) sites)
Oisp
278
8
1561
13

Coma
8


1

Frgr
90
4
491
13

Sabi
173
1
713
24

Jaca
249
21
554
13

Savi
1483
10
5848
70

Lica
209
3
816
11

Spfo
716
3
3217
28

Lose
5


1

Suca
153
1
882
20

Mol i
877
6
1351
6

Trma
178
7
792
30

Sabi
93
1
466
10






a Species abbreviations from Table 3.

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Penasquitoes. Distich!is spicata was more productive than Spartina at Bolsa.
Indeed, Spartina at Bolsa appeared to partially die back in early 1978 with
only poor aerial growth evident" the following summer, expecially at BB-5. Low
production species—Cuscuta sal ina, Lotus scoparius, Cordylanthus maritimus—
were of limited occurrence.
Substrate
Salinity
Substrate interstitial salinity at the upper root zone (0 to 5 cm) and
sub'-root zone depth (45 to 50 cm) by harvest session is found in Appendices
C.l and C.2. Appendix C.3 contains salinity values for substrate free water.
The peak, root zone1 salinity recorded was 125 ppt (LPL-17, session 2); the
minimum root zone value was 5 ppt (UNB-7, session 2; UNB-7 and UNB-8, session
3). The sub-root zone salinity maximum1 of 105 ppt occurred at SRE-15 (session
7); the minimum of 3 ppt occurred at UNB-1 (session 3). Free-water salinity
minimum and maximum were, respectively, 103 ppt (SRE-15, session 3) and 3 ppt
(UNB-1, session 2 and; 3). In general, root zone, salinity for most macroplots
was low in spring (sessions 3 and. 4) and high in summer (sessions 5, 6, 7).
Sub-root zone salinity followed somewhat similar patterns, and free water
salinity tended to be intermediate between root and sub-root zones.
Comparison of mean harvest session salinities by depth and marsh (Figure
7) showed a summer peak for Sweetwater, Newport and Bolsa, a winter peak for
Los Penasquitos. Comparison of salinities over the year in the root zone and
sub-root zone revealed that winter precipitation reduced surface concentration
and increased salinity at depth, while: summer drought tended toward greater
concentration of salts at the surface. Los Penasquitos and, to a degree
Bolsa, were somewhat out of phase with Sweetwater and Newport with higher
surface salinities persisting through fall and winter and lower suface
salinities in the summer. Perhaps the lack of tidal inundation during the
summer at Los Penasquitos and Bolsa was responsible, but the reason for this
is obscure. Annual mean salinities for the two depths were remarkably close,
suggesting that overall variation for the substrate profile was slight.
Overall "saltiness" as revealed by annual means was greatest at Sweetwater,
least at Bolsa, and intermediate at Newport and. Los Penasquitos, although the
former recorded greater mean surface salinity than the latter.
Reacti on
Substrate pH (Appendix C. 4) ranged from 5.2 (UNB-17, session 7) to 8.8
(UNB-1, session 2). Marsh harvest session means (Figure 8) for Sweetwater,
and Newport peaked in the neutral range in the spring and revealed a shift to
slightly acid conditions in the summer; means for Los Penasquitos peaked at
slightly basic in the fall and reached a minimum of slightly acid in the early
summer; means for Bolsa remained neutral to slightly basic throughout the
year.
26

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Figure 7. Mean interstitial salinity (ppt) of substrate at 0-5 cm depth (solid line) and 45-50 cm (dashed
line) ± S.E. for study areas through the sample period.

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Ammonia
Ammonia in substrate free-water varied greatly (Appendix C.5). The
lowest value "of 1 x 10-5M occurred in. numerous macroplots in spring; the high
value was 120 x TO-5 M (UNB-25, session 1). Occasionally an.insufficient
quantity of soil free-water to test with the specific ion electrode was
recovered, but it was felt that the data available did adequately represent
trends in NH3. Mean NH3 values were generally highest in summer and lowest in
spring (Figure 9). Sweetwater and Newport showed an increase in soil ammonia
from spring to early summer, then a decrease in middle and late summer fol-
lowed by a second increase in fall. Ammonia at Bolsa did not follow this dual
maxima pattern, and the lack of data; for session 1 at Los Penasquitos leaves a
question of where this marsh fits. With reference to annual means, Bolsa was
clearly the best supplied with NH3, followed by Newport.
Redox
Redox potential (Eh) of substrate free-water (Appendix C.6) was lowest at
BB-4 (-126 mV^, session 3) and highest at UNB-12 (542 mV, session 2). Low
(<200 mV) and- negative potentials were most persistent at Bolsa;. Sweetwater
displayed most consistantly high potentials. Gaps in the redox record (e.g.,
LPL, session 1; SRE, Session 2) were caused by a malfunction of the platinum
electrode and, after the defective electrode was replaced, by insufficient
sail free water to obtain a measurement. Even thougfr-data-for-aW-HnaeropTotj
over all sessions was lacking, mean redox values (Figure 10) did reveal that
low potentials, and hence prolonged anaerobic conditions—values <200 mV
suggest the presence of reduced iron and manganese (Hesse 1972, Stolzy and
Fluhler 1978)—were characteristic only of Bolsa and that the other study
marsh substrates were- predominately aerobic. This was not surprising,
through, because only at Bolsa were sample sites waterlogged at each visit,
and only there was H2S frequently sensible.
Water content
Appendices C.7 and C.8 present root zone and sub-root zone percent water
content of substrate samples. Minimum and maximum for each depth were 0
(UNB-7, session 5) and 89 (BB-3, session 3; BB-5, session 4), and 16 (LPL-8,
session 1) and 70 (UNB-5, session 4), respectively. Means for harvest
sessions (Figure 11) revealed that root zone water content was very frequently
above water content at depth. This is explained by the nearly universal
nature of substrate profiles—superficial fine-grained silts and clays, often
with high organic content, over sand and silty sand with low organic content.
Thus, even when both depths were saturated, the root zone carried the greater
water proportion. A curious variation on this theme was discovered on
transects UNB-A and UNB-B. Here the upper ends of both transects extended
onto old dredge spoil deposits of high sand and shell content. Because spoil
overlayed the old marsh surface, water content was often greater in deeper
samples. However, lower extensions of both transects support the more common
pattern.
28

-------
*UNB
OBB
i	1	1	1	1	1	1	1	1	1	1	1
OND	JF	HAM	J	J	A	S
1977	1978
Figure 8. Mean pH of substrate soil free-water ± S.E. for study areas through the sample period.

-------
^0 n
30 -
X.
in
z.
o
o
cn
20 -
10
0 J
* UNB
O BB
* SRE
$ LPL
i	1	1	1	1	——i	1—	1	r
ONDJFMAMJ
1977	1978
~i
A
Figure 9. Mean ammonia (10-^m) of substrate free-water ± S.E. for study, (areas through the sample period.

-------
>
e
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X (D
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tr ^3
500 -i
400-
300-
£ 200 H
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N	D
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T"
F
~T"
M
—r
A
0
	r~
M
1978
1	1	r
J	J	A
Figure 10.
(lean redox potential (Eh-mV) of substrate free-water ± S.E. for study areas through the sample
period.

-------
SRE
LPL

%

5			1
I	~l	1-
O N D
1977
~r
F
M
~I	r~
A M
1978
~r
J
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80
70
60
50
40
30
20
10
0
2
l-
w
T. 80
o
in
70
60
50
AO
30
20
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UNB
BB
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i-	£--- —s-'

~i	r~
N D
1977
r~
F
P
M
~r
A
~r
*1
1978
~~r
J
"T"
A
Figure 11. Mean water content (% of moist weight) of substrate at 0-5 cm (solid line) and 45-50 cm (dashed
line) ± S.E. for study areas through the sample period.

-------
Seasonal fluctuations in substrate- water content, while not of great
magnitude, were nevertheless apparent. Most macroplots and, indeed, most
marsh harvest session means, showed minimums. in the root zone during the
summer and maximums between October and April. Subr-root zone water
percentages foljowed the general pattern of root zone water content, but were
less, seasonally variable. Annual water content means suggested that Bolsa was
wettest at the surface and driest below, and that Los Penasquitos was driest
overall. Soil dryness at Los Penasquitos was revealed by surface cracks and,
on many occasions, tremendous pressures were required to force the coring
device-into the soil substrate.
Temperature
Substrate temperature' varied with time of year and depth (Appendices C.9
and C.10). The highest temperature recorded for the root zone was 27.8°C
(UNB-7, session 7), for the sub-root zone 23.3°C (SRE-15, session 5). Mini-
mums were 8.3°C (LPL-18, session 3) and 11.7°C (several macroplots at LPL,
session 3) for root zone and sub-root zone, respectively. In general, the
substrate was warmer in the summer than it was in the winter. Root zone
temperatures exhibited a greater annual range than those"atr sub-root levels
and, in most macroplots, annual means for the root zone were higher by about
1°C. However, with reference to harvest session means (Figure 12), it was
clear that an annual pattern of temperature contrasts between the two levels
was present. In December and January temperature increased with depth; little
change of temperature with depth was present February to April, although the
root zone tended to be somewhat cooler in the early part of this period then
somewhat warmer than the sub-root zone in the latter part; June to July temp-
eratures in the root zone were higher than those below; by October a shift to
cooler root zone temperatures then those below was apparent.
Certainly variations in solar radiation through the year exert control on
substrate temperatures, but temperature is also likely to be influenced by
soil mositure from precipitation and tidal inundation and by foliar density of
marsh plants.
Elevation
Sample macroplot elevations referenced to mean high water (MHW) ranged
from -1.12 to 1.17 m (Appendix D). Most macroplots were located above MHW
but,, conspicuously, all macroplots at Bolsa were below this tide level (Figure
13). Because macroplots were positioned to represent the variety of
vegetation patterns in study marshes, macroplot elevations provided a good
approximation of the vertical range of salt marsh.
Habitat Type
Each macroplot was assigned to one of seven habitat types during the
final field session (Appendix 0). This classification represented a priori
judgement and was not based on later knowledge of site_producti.on and analysis
33

-------
1978
Figure 12.
Mean temperature (°C) of substrate at 0-5 cm (solid line) at 45-50 cm (dashed line) ± S.E. for
study areas through the sample period.

-------
1.5 -r
1.0 -
0.5 -
o
S MHW H
-0.5 -
UNB
SRE
LPL
BBC
BBa
-1.0 -
-1.5 -»¦
Figure 13. Vertical range of salt marsh in four southern California
locations (m). SRE is Sweetwater River Estuary, LPL is Los
Penasqu.itos Lagoon, UNB is Upper NewB.ort._BayBB. i_s Inner
Bolsa Bay, BB is Outer Bolsa Bay. Elevation in meters
referenced to local mean higher water.
35

-------
of seasonal trends in environmental variables. The distribution of habitat
types along a hypothetical marsh profile is shown in Figure 14.
Fore Levee Slope (FLS)
Located adjacent to creeks and river channels and bounded on the upland
side by a levee, the Fore Levee Slope habitat had the most intimate contact
with tide waters and occurred at the lowest elevations (Table 9). Species
diversity was low—usually only Spartina foliosa and, less "frequently,
Salicornia virginica and Salicornia bigelovii were present. At marshes with
and Without tidal fluctuation (Sweetwater and Newport versus Los Penasquitos
and Bolsa), substrate salinity in this habitat fluctuated very little; most
readings were near that of sea water. Redox potentials were generally low
and, especially at Newport, often negative. The soil surface tended to heat
rapidly by exposure to the sun at low tide.
Levee Crest (LC)
Levees along water courses were conspicuous in the field although they
were often only 10 cm or less above adjacent marsh. This was often the site
of vigorous growth in Salicornia virginica but, even at Los Penasquitos with
its general low species diversity, multispecies stands were more common.
Salinity extremes were greater here than in Fore Levee Slope, yet less extreme
than other habitats. At Los Penasquitos mean salinity was lowest on levees.
This habitat type was among the best drained; redox was high, soil water fow,
and ammonia low.
Back Levee Slope (BLS)
On the opposite side of the levee from Fore Levee Slope, and at higher
elevations, Back Levee Slope extended away from water courses. This habitat
was fairly well drained, generally high in species diversity, and the most
widespread habitat at Sweetwater and Los Penasquitos. At Sweetwater mean root
zone salinity was highest in Back Levee Slope. * This habitat was universally
low in ammonia.
Back Levee Depression (BLD)
Where water courses were well developed—Sweetwater, Los Penasquitos,
Newport but not Bolsa—Back Levee Slope often ended in poorly drained shallow
depression in which water remained on the surface for long periods after tidal
inundation. Subsequent evaporation of impounded water in this habitat created
high substrate salinity, especially at Los Penasquitos and Newport. Low redox
values and high soil water content suggested persistent anaerobiosis.
Ammonia levels were often high in this habitat, although not as high as those
of Fore Levee Slope.
36

-------
SBU
BLS
BLO
FLS
r~		—		;—;							
DISTANCE
Figure 14.
Location of habitat types along a hypothetical marsh profile. Habitats from left are Fore
Levee Slope, Levee Crest, Back Levee Slope, Back Levee Depression, Slope Below Upland, Upland
Transition, and Pan.

-------
Table 9. Mean Elevation, Number of Species, and Substrate Conditions for Habitat Types
	Annual	Mean 	
Elevation	No.	Salinity	NH^ Redox	Soi1	Sdi1
Marsh Habitat (m)	Species	(ppt)	pH (10-s) (Eh)	Water (%) Temp. (PC) n
M	mV
FLS
-.25
2.0
40
6.5
2.6
340
44
18
3
LC
.31
5.8
48
6.5
1.5
417
46
17
6
BLS
.28
7.6
58
6.3
1.0
405
48
17
8
BLD
. 18
7.1
48
6.5
1.8
335
60
18
8
SBU
.34
5.7
47
6.9
1.2
380
54
17
3
UT
.48
2.0
44
7.0
1.7
384
39
17
2
P
.52
1.0
90
6.9
.7
427
30
19
1
FLS
.21
1.0
39
6.9
2.2
342
48
16
1
LC
.28
1.2
33
6.5
2.5
324
53
15
5
BLS
.21
1.2
39
6.8
2.1
333
48
15
9
BLO
. 16
1.0
44
6.9
1.9
293
43
15
2
UT
.49
2.3
39
6.5
2.5
366
34
16
4
FLS
.30
2.9
35
6.6
12.6
190
65
17
7
LC
.54
6.0
38
6.7
1.7
321
52
16
2
BLS
.50
8.0
38
6.3
1.0
333
69
16
4
BLD
.65
6.6
58
6. 1
3.5
300
71
17
7
SBU
.77
9.0
39
7.2
1.0
344
23
16
3
UT
1.11
2.5
33
8.3
1.0
352
9
18
2
FLS
-1.10
1.5
41
7.3
24.0
-3
78
17
2
SBU
-.91
3.0
29
7.3
6.3
102
80
15
2
UT
-.57
2.0
20
7.0
3.3
208
53
15
1

-------
Slope Below Upland (SBU)
Below* the landward border, a sloping habitat—here labeled Slope Below
Upland—often extended toward a water course or Back Levee Depression. Well
drained and high in species diversity, this habitat type was generally low in
ammonia and moderate in salt concentration.
Upland Transition (UT)
At the ecotone between marsh and upland, the most elevated habitat type-
Upland Transition—was, identified. High redox potentials and Tow root zone
water content denoted good drainage: Relatively low salinity and moderate- to
low ammonia: were characteristic. Species, diversity at Los Penasquitos was
highest in this habitat, but elsewhere the number of species was lower than
might be expected. At Sweetwater and Bolsa, Frankenia grandiflora dominated
this habitat; at Newport Monanthocloe 1ittorlis and an occasional upland plant
species (e.g., Lotus scoparius) were important; at Los Pensquitos upland
transition was taken by a combination of Frankenia grandi flora, Distichli:s
spicata and Cressa truxillensis. Abnormally high pH in this habitat at
Newport was most likely due to disintegration of shell in the substrate.
Pan (P)
Slight depressions at high marsh elevations collected water only from the
highest tides. Through evaporation, expecially in the summer, salts were then
concentrated and left at the surface. The Pan habitats were present in all
four study marshes, but generally they contained little vascular plant life.
At Sweetwater, however, a pan containing stunted growth of Salicornia
v-irginica was sampled (SRE-15). Mean root zone salinity for this site was the
highest recorded for all macroplots. Redox potential and root zone tempera-
tures were high; ammonia and soil water were low. This habitat represents
perhaps the most extreme marsh environment.
Net Production and Environment
Stand net production and elevation
Strength of the relationship between macrpplot NAPP and elevation varied
between study marshes (Figure 15). At Bolsa production increased dramatically
with elevation (R = .85); relationships were positive but less dramatic at Los
Penasquitos (R = .55) and Sweetwater (R = .43). No correlation between net
production and elevation was detected at Upper Newport (R = -.08).
Species net production, elevation and plant communities
Plant species occupied marsh with certain elevational limits in study
areas, and elevations of peak species production were generally unique (Figure
16). Moreover, vertical distribution of species and production peaks sug-
39

-------
7000
6000
z 5000
o
£ 4000
g 3000
£ 2000
1000
0
SRE
/
—i	1	1	1	1
-.2 0.0	.2
1	1	1	1
.4	.6

7000

6000 -

5000-
z

o

H
H
4000 -
o

n

o
o
3000 -
at

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2000 -
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z


1000 -

0 -
LPL
(	1	1	1	1	1	1——i	1	t-	1—
2 0 0	2	.4	.6	.8
ELEVATION (m)
Figure 15.
Macroplot net production and elevation,
referenced to local mean high water.
7000
6000 -
5000 -
4000 -
3000
2000 -
1000-
0
UNB
i	r~
.2
—i	1	1	1	1	1	1	1	1
.4.6	.8 1.0 1.2
7000 t
6000-
5000-
4000"
3000-
2000"
1000-
0-
BB
i	r
-1.2
—i	1	1	1	1	t	'	»~
•1.0 -.8	-.6 -.4
ELEVATION (ra)
- . 2
Production is SSTC in g m-^r-1; elevation (m)

-------
lose jk
igure 16. Elevational range of plant speqjes in macroplot samples. Peak corresponds to elevation
maximum production. Elevation (m) referenced to local mean high water.

-------
gested several plant communities along, the elevation gradient in each marsh.
At Sweetwater pure stands of Spartina foliosa extended to mudflat, but at
elevations between -.1 and .1 m MHW, Spartina foliosa joined Salicornia
virginica,. Salicornia bigelovii and Bat is mantima to form a multispecific
commumty—Low Marsh. The High Marsh community at Sweetwater occurred between
.1 and .5 m and was highly diverse; the Upland Transition community consisted
of pure stands of Frankenia grandiflora above .5 m.
Communities similar to those present at Sweetwater occurred at Newport
but with some notable exceptions. Spartina foliosa dominated the entire Low
Marsh and"; Frankenia grandi flora did not constitute the Upland Transition.
Instead Monanthocloe 1ittoralis, Distichlis spicata and occasionally Limonium
californicum occupied the highest levels.
Only High Marsh and Upland Transition communities were discernible at Los
Penasquitos. Salicornia virginica and Frankenia grandiflora dominated the
former; the latter was dominated by Frankenia grandiflora, Distichlis spicata
and Cressa. tfuxillensis.
Low Marsh, High Marsh and Upland Transition were present at Bolsa. Pure
stands of Spartina foliosa comprised Low Marsh; Salicornia virginica and
Oistichlis spicata, with Some Sparti na foliosa and Frankenia grandiflora,
inhabited High Marsh; Frankenia grandiflora and limited Distichlis spicata
occurred in Upland Transition. Plant communities recognized in this study
were essentially synonomous with the "low," "middle," and "high littoral" of
other authors (Purer 1942, Vogl 1966).
That peak production for each species usually occurred at an elevation
unique to the species supported the principle of competitive exclusion (Gause
1934) that I observed in an investigation of species-elevation relationships
in Oregon salt marshes (Eilers 1976). But it should be noted that in both
investigations arrayment of plant species along an abstract elevation gradient
suggested "abstract communities and, that in the field, the vegetation appeared
more' as a complex mosaic.
Stand net production and habitat type
Variation in production between habitats was significant (pc.QOl).
Clearly two habitat types, Levee Crest and Upland Transition accounted for the
greatest macroplot production (Figure 17). This suggested that good drainage
and associated aerobic soils., moderate salinities, and moderate to low soil
ammonia provided conditions associated with optimal plant growth. In
contrast, Fore Levee Slope and Back Levee Depression showed the lowest mean
production (with the exception of Pan habitat) and thus anaerobic substrate,
high root zone water content,, high soil salinity, and high ammonia were less
supportive of high yield.
Back Levee Slope and Slope Below Upland habitats recorded moderate yield
which was perhaps a reflection of moderate environmental conditions comprising
these types. Of the two, however, Slope Below Upland tended to be the more
productive; the difference was likely attributable to slightly higher eleva-
42

-------
5000
4000-
3000-
2000
1000-
0-
5000
4000-
3000-
_T 2000-
I
^ L000
I
E
30
z
o
a
O
a:
a.
fr-
bJ
Z
0 ™

5000 -j

4000 -

3000 -


T
2000-
¦ O
' X
1000 -

0 -

5000 i

4000 -

3000-

2000-
T
1000-
f
0
1
0 -
1
BB
FLS
—r-
LC
BLS
BLD
HABITAT
SBU
UT
Figure 17.
Mean net production (g . nryr-1, SSTC) by habitat type (±S.E.).

-------
tion in this habitat. Inhibitory effects of high salinity appeared to out-
weigh benefits of high elevation and good soil aeration in the Pan habitat
type.
Species net production and habitat type
Even though most plant species occurred in more than one habitat type,
each displayed maximum production and therefore maximum affinity to a par-
ticular type in each marsh (Table 10). Fore Levee Slope was favored by
Spartina foljosa, and Salicornia bigelovii grew best in this habitat only at
Sweetwater. Sal icornia virginTca achieved maximum production in Levee Crest
where this habitat was available. Jaumea carnosa, Triglochin maritimum and
Cuscuta salinia did best in Back Levee Slope and Back Levee Depression; Batis
maritima produced at maximum in Back Levee Depression at Newport and Slope
Below Upland at Sweetwater. Peak production of Limonium californicum and
Suaeda californica occurred in Slope Below Upland.
Habitat affinities of several species varied from one marsh to the next.
Most curious in this regard was Frankenia grandiflora. Upland transition was
its most productive habitat at Sweetwater and Bolsa; at Los Penasquitos, while
more productive in Back Levee Slope, it produced high yield_s in Upland
Transition. However, at Newport, its maximum growth (a low 134 g m-2yr-1)
occurred in poorly drained Back Levee Depression habitat. Two explanations
were possible. Competition with Monanthocloe littoral is may have excluded
Frankenia grandiflora from Upland Transition at Newport, or perhaps, coarse
grained substrate there favored Monanthocloe littoral is but did not retain
enough moisture- for establishment of Frankenia grandiflora. At any rate,.the
low production of Frankenia grandiflora at Newport merits further investiga-
tion. Distich!is spicata" displayed the greatest variation in habitat
affinity; it achieved maximum production in a different habitat in each study
marsh.
From the foregoing it was clear that, while for some species maximum
production always occurred in the same habitat or closely related habitats
(e.g., Sparti na foliosa, Jaumea carnosa), peak production for other species
(e.g., Distich!is spicata) was prone to intermarsh variability.
Explanatory models: net production and environment
Pearson correlation coefficients which indicate the degree to which two
variables covary were computed for NAPP (as SSTC) with macroplot elevation,
number of species, and annual values (mean, minimum, maximum and range) for
substrate variables (Table 11). On the strength of coefficients, eight
independent variables were selected for stepwise multiple regression analysis
as noted in the table. Table 12 resulted from the initial analysis. For
Sweetwater, root zone temperature entered the regression equation on the first
step with a significant R2 of .54. The addition of root zone water content,
root zone salinity, elevation, and free water ammonia on successive steps
created a regression model that explained 72 percent of the observed variation
in._macr.op lot production. Subsequent steps did not add to the model. Salinity
44

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Table 10. Mean Species Net Production for Habitat Types (g m-Syr-1)
SRE
LPL
UNB
BB
Habitat
Species
FLS
LC
BLS
BLD
SBU
UT
Bama

96
151
215
919

Cusa

2
238
74
28

Disp

238
443
78


Frgr

773
488
137
698
4838
Juca

104
465
981


Li ca

288
68
157
476

Moli

303
241
49


Sabi
458

182
330
3

Savi
1122
2196
1048
810
1020
131
Spfo
2034
3
166
175


Suca

149
83
97
363

Trma

43
166
178
197

Crtr





127
Disp





1184
Frgr

2574
3347


3459
Savi
1767
4006
2499
2636

1585
Bama
155
198
.81
509
45

Coma




8-

Cusa
1


5


Disp

780
444
70
152
401
Frgr

27
14
134
101

Juca
284
96
392
184
88

Lica

3
67
57
522
357
Lose





5
Mol i



6
969
1175
Sabi
1
1
223
67
1

Savi
324
1980
175
764
357

Spfo
1661
50
52
194.


Suca

16


155

Trma:
63
261
352
187
53

Disp




891
74
Frgr




72
4564
Savi
459



1323

Spfo
598





665
45

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Table11. Pearson Correlation Coefficients for NAPP with Elevation, Number of
Species and Substrate Variables. Variables Selected for Regression
Analysis are Indicated.
Variable
SRE
LPL
UNB
BB
AL-t
Elevation a
.43
.55
-.08
00
en
.07
Number of Species a
.13
.51
.02
.60
.09
Salinity x3''3
-.30
-.53
-.39
-.79
.27
min.
-.17
-.24
-.32
-.76
-.19
max.
-.27
-.19
-.18
-.41
.06
range
-.20
-.15
-.02
.62
.13
pH xa
.10
-.45
.07
-.70
-.06
min.
.01
-.28
.02
-.79
-.08
max.
.01
-.31
.24
-.37
-.04
range
-.12
-. 07
.34
.09
.01
NHS- x
-.10
-.38
-.03
-.57
-.26
min.
.17
-. 32
-.19
.19
-.19
max.
-.18
-.38
.09
-.86
-.25
range
-.18
-.38
.09
-.86
-.25
Redox x
.45
.05
.04
.70
.30
min.a
.45
.32
.26
.74
.37
max.
.23
-.03
.21
.37
.18
range
-.27
-.38
-.16
-.86
.39
Soil Water x3'*3
-.19
-.14
-.19
1
cn
-.32
min.
-.29
-.12
-.25
-.48
-.38
max.
-.03
-.20
-.17
-.51
-.19
range
.38
.03
.34
.40
.31
Temperature xa'^
-.74
-.08
-.66
-.73
-.42
min.
-.46
.31
.01
-.68
-.38
max.
-.13
-.38
-.45
-.85
-.24
range
.18
-.49
-.37
-.93
-.11
^Selected as independent variables for regression analysis.
Root zone
46

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Table 12. Summary of Stepwise Multiple Regression—NAPP with Elevation;
Number of Species; Root Zone Salinity, Water Content, and Temp-
erature; and Soil Free-Water Ammonia, Redox and pH.

Step
Variable
Enteri ng.
Multiple R
R2
Simple R
SRE
1.
Temp
.74
.54
-.74

2.
Water
.76
.58
-.19

3.
Salt
.79
.62
-.30

4.
Elev
.83
.68
.43

5.
nh3
.85
.72
.17

6.
Sped es
.85
.72
.14

7.
Redox
.85
.72
.45
LPL
1.
Salt
.53
.28
-.53

2.
Spp
.73
.54
.51

3.
Elev
.78
.61
.55

4.
Temp
.79
.63
-.08

5.
Water
.79
.63
-.14

6.
Redox
.79
.63
.32

7.
pH
.79
.63
-.45

8.
nh3
.79
.63
-.32
UNB
1.
Temp
.70
.49
-.70

2.
Water
.74
.54
-.23

3.
Salt
.75
.56
-.39

4.
Species
.77
.60
.00

5.
Redox
.78
.61
.26

6.
nh3
.79
.62
-.20

7.
pH
.79
.63
.15

8.
Elev
.79
.63
-.01
BB
1.
Elev
.85
.73
.85

2.
Species
.99
.98
.60

3.
Water
.99
.99
-.53
entered the equation first for Los Penasquitos (R2 = .28) followed by species
and elevation. The three variables together accounted for 61 percent of the
variation in production; continuation of the stepwise process.added little.
Temperature was again the first independent variable to enter for Newport (R2
= .49) and, on the next step, it was joined by root zone water content to
explain 54 percent of NAPP variation. Addition of the remaining variables
increased the explanation by small increments to 63 percent. Elevation and
number of species provided a strong combined R2 of .99 for Bolsa, but soil
water content was the only additional variable to enter and it added little.
47

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Analysis to this point suggested that high root zone temperature was an
important constraint on NAPP in tidally controlled marshes. It might be
expected that more frequent inundation at lower elevation moderates temp-
eratures, yet the correlation between mean root zone temperature and elevation
at .Sweetwater was strongly negative (R = -.67). At Newport, however, this
correlation was moderately positive (R = .23) and supportive of a tide-
temperature relationship. A check of mean temperatures recordied for Newport
macroplots revealed that those contributing most to the-positive- correlation
were located on old dredge spoil and thus this apparent positive relationship
should be approached cautiously. Furthermore, the question of temperature
modification by marsh plants needed to be considered. It was reasoned that
high production should correlate well with low root zone temperature because
of shading by high foliar density and, therefore, high production itself could
be partially responsible for lower soil temperature. Inclusion of number of
species was also questionied because, as a vegetation characteristic, its
presence in the analysis would not help to explain variation in NAPP in terms
of environmental factors.
With these considerations in mind, temperature and number of species were
excluded from the independent variables and regression models recomputed
(Table 13). Redox, elevation, and root zone salinity combined in a new model
for Sweetwater to explain 56 percent of NAPP variation; addition of NH3 and
water content of the root zone increased the R2 to .66. The combination of
salinity, elevation, NH3, salinity, and pH produced R2 = .56 at Los
Penasquitos. Salinity and redox were most important (combined R2 = .26) at
Newport, but the expansion of the regression equation to include elevation,
soil water, and pH increased the R2 by .11. Elevation, soil water and soil
salinity entered the equation for Bolsa (R2 = .99). Treatment of all marshes
together produced a combined R2 for redox and salinity of .29, but further
addition of variables did not improve the multiple R2.
A combination of variables provided at least a partial explanation of
NAPP variation in each study marsh, but variables related to soil aeration and
waterlogging (redox, soil water content, and, in some ways, elevation) and
soil salinity were consistently important constraints on production. The
models suggested that high production was most likely to occur at well-
drained, aerated, low-salinity locations (such as Levee Crest and Upland
Transition habitats) and that low production could be expected in sites where
water collects on the marsh and remains for long periods (Back Levee
Depression and Fore Levee Slope habitats). Low production could also be
expected where elevated soil salinity results from evaporation of surface
water (Back Levee Depression at Los Penasquitos and Newport and Pan at
Sweetwater). Production was apparently not limited by nitrogen (NH3) as
suggested by Valiela and Teal (1974). Only in the regression model for
Sweetwater did a positive relationship with ammonia occur.
Strength of regression models varied between marshes, but the general
levels of explanation for differences in macroplot production were high and
significant (all < .14). A search for the source of unexplained variation in
production (1 - R2) through computation and graphic presentation of residuals
to each model produced no consistent patterns. Perhaps the inherent vari-
ability of marsh vegetation and limitations imposed by sampling each time at a
48

-------
Table 13. Summary of Stepwise Multiple Regressiorr-NAPP with Elevation;
Number of Species; Root Zone Salinity, Water Content, and Temp-
erature; and Soil-Free Water Ammonia, Redox and pH.

Step
Variable
Enteri ng
Multiple R
Multiple R2
SimpleR
SRE
1.
Redox
.45
.21
.45

2.
Elev
.59
.36
.43

3.
Salt
.75
.56
-.30

4.
nh3
.78
.62
.17

5.
Water
.81
.66
-.19

6.
PH
.81
.66
. 10
LPL
1.
Salt
.53
.28
-.53

2.
Elev
.69
.47
.55

3.
nh3
.71
.50
-.31

4.
Water
.72
.52
.32

5.
Redox
.75
.56
.32

6.
PH
.75
.57
-.45
UNB
1.
Salt
.39
.15
-.39

2.
Redox
.51
.26
.26

3.
Elev
.53
.28
-.01

4.
Water
.56
.31
-.28

5.
PH
.61
.37
.14
BB
1.
Elev
.85
.73
.85

2.
Water
.93
.87
-.54

3.
Salt
.99
.99
-.79
All
1.
Redox
.37
.14
.37

2.
Salt
.54
.29
27

3.
nh3
.54
.29
-.19

4.
PH
.54
.29
-.06

5.
Water
.55
.30
-.32

6.
Elev
.55
.30
.07
different position within macroplots were factors. Other variables not
included in this investigation (such as soil texture, soil nutrients other
than ammonia-N, water table depth, and animal trampling and herbivory) could
have provided additional explanation.
49

-------
DISCUSSION
Disappearance of Dead Material
The rate at which dead material disappears from the marsh is closely
related to several factors including temperature, precipitation, tides, and
the organic nature of marsh plants (Kirby and Gosselink 1976). Rates could be
expected to vary with seasons and with the mix in species composition as was
observed in this study. Wiegert and Evans (1964) suggested two methods-
litter bags and' paired plots—by which to estimate the disappearance of dead
material and applied each in a study of old field vegetation in Michigan.
Subsequently, several authors applied one or the other of these techniques to
investigations of salt marshes along, the Atlantic and Gulf Coasts of North
America, The range of their estimates,, those of Wiegert and Evans (1964), and
estimates generated by this study are presented in Table 14. Disappearance
rates for southern California marshes compare closely to those obtained by the
litter bag technique elsewhere, but litter bag estimates are, in general,
lower than values obtained by utilization of paired plots. Litter bags
exclude larger detritivores and retard water movement that might otherwise
remove dead material (Hopkinson et aK 1978). The paired plot technique is
more sensitive to tidal deposition and removal of dead material and to
consumer activity. Therefore, paired plots are likely to approximate decom-
position under natural conditions better than the Titter bag methods. Thus,
even though disappearance rates determined by the litter bag technique provide
insight into the decomposition process and allow adjustments to dead biomass
for computation of NAPP, resultant production is probably somewhat under-
estimated by this method.
Net Production
Role of tidal fluctuation
The importance of tidal action to nutrient cycling and production in salt
marshes is well recognized (Odum 1961, Teal 1962, Steever et ah 1976) and
most, if not all, previous investigations have been confined to salt marshes
with unrestricted tidal access. The inclusion of Los Penasquitos and Bolsa in
this study allows comparison of production with and without regular tidal
control. It appears that in southern California, salt marsh macrophyte pro-
duction may be helped by restricted tidal contact. Mean production at Los
Penasquitos was 1.3 to 1.6 times greater than that at Sweetwater and 1.9 to
2.2 tiroes greater than Newport (based on ST and SSTC values). Waterlogging
reduced production at Bolsa and the anomalously low. level of the marsh there
prevents direct comparison with Los Penasquitos or other sites, but it may be
noted that production of macroplot BB-1:was above that of all Newport sites
50

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Table 14. Disappearance Rate of Dead Material in Michigan and Salt Marshes
along the Atlantic and Gulf Coasts of North America Compared to Salt
Marshes in Southern California (mg g-1day-1). The Range of Values
Contain Means for Plant Species Sampled.
Method
Source
Locale
Litter
Bags
Pai red
Plots
Wiegert and Evans (1964)
Michigan
.3 - 4.6
1.3-13.6
Linthurst and Reimold (1978)
Mai ne to
Georgia

.1 - 34.8
Odum and de la Cruz (196?)
Georgia
1.2. - 3. la

Kirby and Gosselink (1976)
Louisiana
4.9 - 6.3a

White et a1_. (1978)
Louisiana
CM
CO
i

Hopkinson et ah (1978)
Louisiana

4.0 - 18.9
This Study
California
.7 - 3.7

aSpartina alterniflora only.
and above the mean for Los Penasquitos. Conditions in the lagoon are perhaps
near ideal for growth of Salicornia virginica and Frankenia grandiflora;
elsewhere both exhibit greatest vigor in well-drained levee and high marsh
sites with infrequent inundation. Tidal access to Los Penasquitos is
restricted to winter and spring months when the marsh is less photo-
synthetically active. Lack of tidal fluctuation may further support high
production in Salicornia virginica and Frankenia grandiflora by reduction of
species diversity.
Nearly all plants recorded in all sample macroplots occurred at
Sweetwater and Newport, and polyspecific stands were very common in both.
Monospecific stands characterized Los Penasquitos and Bolsa, and the total
flora recorded from these sites was limited to five and four species,
respectively. Furthermore, the mean disappearance rate of dead material at
Los Penasquitos was 1.3 times Tower than that for Sweetwater and 1.5 times
lower than that for Newport. This implies that nutrient cycling at Los
Penasquitos is retarded in comparison to tidally controlled sites; but higher
production, larger litter accumulation, and infrequent inundation at Los
Penasquitos suggests that nutrients tend to remain on site and benefit marsh
plants rather than estuarine organisms as is likely to be the case with
regular tidal flushing.
51

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Elevation versus habitat
In an earlier investigation of an Oregon coastal salt marsh (Eilers
1979), I observed an increase in macrophyte production with elevation, but
production in certain sites such as creek levees ancLback.._lev.ee depressions
did rrart conform to the general gradient pattern. Little reference to
production ecology appears in the literature, but numerous authors who have
studied Atlantic and Gulf Coast marshes report higher production of Spartina
alterniflora on creek banks than in inland areas (for example, Smalley 1959,
Kirby and Gosselink 1976). Brereton (1971) found that Salicornia grew with
greatest vigor in aerated, soils; Puccinellia maritima performed best in water
logged soils. This^ leads- to the question of the relative importance of
elevation and habitat in terms of production levels. The current investiga-
tion of southern California marshes sheds some light on this question. It.
appears that the strength of the relationship between production and tide
levels depends on the marsh under consideration. A very strong positive
relationship occurred at Bolsa-, no relationship was detected at. Newport, and a
moderately positive relationship was observed at Los Penasquitos and Newport.
Winfield and Zedler (1976) found a parabolic relationship between net pro-
duction and elevation classes in salt marshes of the Tijuana River Estuary
(southern California) with-the dip at mid-elevations. Mahal 1 and Park (19.76a)
recorded minimum production at the Spartina-Salicornia ecotone in San
Francisco Bay. To. relate production to elevation alone may, therefore,
produce conflicting results. As this investigation suggests, production in
salt marsh vegetation is more tuned to a combination of environmental
factors—soil water content, redox potential, salinity, inundation period, and.
elevation—than to an abstract elevation gradient alone. Indeed, elevation
controls inundation period, but microtopography and soil texture control
drainage. The degree of drainage in turn influences soil aeration, salinity,
redox potential, pH and nutrient levels. At any given elevation, several
different habitats—each composing a different combination of environmental
variables—may occur. Back levee depressions may be found at the same
absolute elevation as levee segments, and intramarsh Pan may occur at the same
elevation as Upland Transition. Furthermore, microtopography may be
influenced by tide level to create- strongly contrasting habitats. Poorly
drained areas at low elevation—Back Levee Depressions—are perpetually water-
logged, but frequent tidal inundation prevents extreme salt concentrations.
Infrequent tidal flooding of elevated depressions—Pan habitat—leads to very
high salt concentrations in the soil root zone through prolonged evaporation,
but soils are generally not waterlogged and redox potentials are high. It
appears, then, that habitat exerts greater control over production of salt
marsh vegetation than does elevation (and tidal inundation) alone. This
suggests that if a strong relationship between production and elevation is
observed, as at Bolsa, the various, habitats are not fully represented and/or
the spatial arrangement of habitats supports the production-elevation
relationship. Creek levees and Back Levee Depressions are hot present at
Bolsa and, because soil salinity and waterlogging decrease sharply with
increased elevation, the strong positive relationship is not surprising. The
weak production-elievation relationship at Newport attests to the occurrence of
contrasting habitats (and hence different levels of production) at similar
elevations.
52

-------
Comparison with other salt marshes and latitudinal trends-
Reported studies of production in salt marshes along the Pacific Coast of
North America are scarce, and thus a comparative treatment is difficult. The
task if further complicated by the lack, as Kirby and Gosselink (1976) found
when they sought comparisons for their work in Louisiana, of uniformity in
methodology among studies. Table 15 brings these reported studies together
and comparisons, at least among estimates dierived by similar methods, are
possible. Production in the four southern California marshes studied is from
1.5 to 2.8 times greater than that of Nehalem Bay. This is not unexpected
because production in Oregon is confined to the warm months, and aerial
portions die back to ground level each fall.
That all four marsh estimates (SST) from1 this study are well above values
computed for Tijuana River Estuary by Zedler and Maurillo (1979) is curious.
Sweetwater is located closest to Tijuana; they are similar in species com-
position and. setting (estuaries with some fresh water inflow), but production
in monospecific stands of Spartina foliosa is 2.5 times greater at Sweetwater
(2033 versus 832 g m-Syr-1). Steever et al. (1976) found that production of
Spartina alterniflora in Connecticut marshes increases with tidal range.
Sparti na foliosa is the ecological equivalent of Sparti na alterni flora in
California marshes. Tide range (MLLW to MHHW) at Sweetwater is 1.8 m; tide
range at Tijuana has not been published. However, the National Ocean Survey
has operated a tide recording station on the municipal pier at Imperial Beach
since 1971. The pier extends into the Pacific Ocean 2.5 km northwest of the
entrance to Tijuana Estuary, and tide range there is 1.6 m—very close to that
at Sweetwater. Warme (1971) reported poor establishment of Spartina foliosa
at Mugu Lagoon where tidal range is reduced to .4 m by a sill of accumulated
sand at the lagoon entrance. The disparity in production levels for Spartina
(and perhaps other species) between Sweetwater and Tijuana suggests that a
reduced tidal range similar to that at Mugu Lagoon is present at Tijuana.
There could also be differences in method between the two studies that are not
apparent. Obviously, more research into this matter is needed.
Zedler and Mauriello's (1979) production estimate of 2792 g m-2yr-1 for
pure stands of Salicornia virgi ni ca at Los Penasquitos in 1978 is close to
pure stand mean of 3062 g m-^yr-1 (SST) produced by this study. This level of
production Los Penasquitos may not, however, be achieved every year for Zedler
and Mauriello (1979) reported Salicornia virginica growth in July-August 1978
to be 2.4 times that of 1977 for the same period. They contend that greater
rainfall and partial impoundment of runoff due to late spring entrance closure
in 1978 are responsible for the disparity. This interpretation is open to
question. I observed water levels in June 1977 to be-.4 m higher than in June
1978 (entrance closed at both times) and, while 1978 was indeed the wetter
year, August 1977 was one of the wettest on record (NOAA 1977, 1978). This
suggests that prolonged inundation of the marsh in late spring and summer 1977
held July-August production to an abnormally low level and that high
production returned with the more favorable inundation-moisture balance of
1978.
Because production estimates of Eilers (1979), Hoffnagle et a]_. (1976)
and those of this study are based on nearly identical methodology, some
53

-------
Table 15. Net Production for Salt Marshes Along the Pacific Coast of North America (g m-2yr-1)
Source
Locale
Production
Method
Burg et aK (1975)
Puget Sound
750a, 90-1400b
Max.-min. live standing

Washington
a h

Eilers (1979)
Nehalem Bay
1400 , 227-2800°
SST9

Oregon


Hoffnagle et al_. (1976)
Coos Bay
380-1100°
SST

Oregon
r r

Cameron (1972)
San Francisco Bay
1200-1700
Peak live standing crop

California


Mahal 1 and Park (1976a)
San Francisco Bay
960C, 690C
Peak live standing crop

California

k
This Study
Bolsa Bay
2494 (2368)a
SSTC (SST)

California



Upper Newport Bay
2150 (2034)a


California



Los Penasquitos Lagoon
3787 (3539)a


Cali fornia



Sweetwater River Estuary
3196 (2943)a


California


Zedler and Mauriello (1979)
Los Penasquitos Lagoon
2792C
Increase in live + increase

California

in dead standing crop

Mission Bay
544C


Cali fornia
H a f


Tijuana River Estuary
832°, 971 , 944
SST
k Marsh mean
Community means
^ Salicornia virqinica mean
Spartina~~fol losa mean
e
f
9
Middle marsh mean
High marsh mean
Method of Smalley (1959) applied to species with
summation of species production.
SST corrected for losses due to disappearance of dead
material.

-------
observations on latitudinal trends in production along the Pacific Coast are-
possible. I suggested earlier (EiTier's 1979) that salt marsh production might
be expected1 to decrease with decreasing latitude as summer aridity increases
soil salinity. While maximum soil salinity, in Oregon marshes (Eilers 1975) is
3 to 10 times less than that observed in this study, net production based on
marsh means is 1.5 to 3.0 times greater in southern California. It appears
that summer drought and increased soil salinity at lower latitudes are more
than compensated for by the warm temperatures and high _light levels that
promote a year-long growing season. But these observations are" tentative at
best. Clearly, more work and a convergent methodology are needed before
latitudinal trends in production along this coast can be firmly-established.
Turner (1976) reviewed: and', in some cases, recalculated estimates, of
macrophyte production in salt marshes of the Atlantic and Gulf Coasts and
observed an increase in production with decreasing latitude. Comparsion of
estimates recalculated by the Smalley (1959) method with those of this study
suggest that marsh production in southern California is close to, if not
greater than, that of similar latitudes. For example,, net production of tall
Spartina alterniflora in Mississippi is 1964 g m-2yr-x (de la Cruz 1974 in
Turner_ 1976); the ST mean for all pure^ stands of Spartina foliosa sampled at
Sweetwater and Newport is 2051 g m-2yr-1. Kirby and Gosselink (1976)
estimated net production of Sparti na alterni f1ora on creek banks and inland
sites in Louisiana coastal marsh at 2645 and 1323 g: m-2yr-1, respectively,
using the method of Wiegert and Evans (1964). The comparable SSTC mean for
pure stands of Sparti na foliosa (2272 g m-2yr-1) is near the creek bank value,
but mean production for this study based on SSTC for all macroplots (3135 g
m-2yr-i) is greater than both figures. Hopkinson et ah (1978) studied pro-
duction in seven marsh: macrophytes in Louisiana by the Wiegert and Evans
method. Mean production in pure stands of Salicornia virginica at Los
Penasquitos (SSTC = 2789 g m-^r-1) is- nearly equal to that of Distich!is
spicata; greater than Phragmites communi s, Sagittaria falcata, Spartina
al term flora and Sparti na cynosuroides; but less than half that of Spartrna
patens. That the high level of salt marsh production reported for low
latitudes on the Atlantic Gulf Coasts is duplicated in southern California
marshes, supports the universality of a latitude-production gradient.
The Spartina Question
Sparti na fol iosa dominates . low marsh environments from northern
California (Humboldt Bay) to the southern most extent of salt marsh at Laguna
Ojo de Liebre, Baja California (Phleger 1965, Macdonald 1967). A tall (1 m)
rhizomatous grass with prominent aerenchyma tissue, Spartina foliosa is
capable of withstanding long submergence (Purer 1942). Macdonald 0~977)
recognizes two distinct groups of estuaries and coastal lagoons in southern
California based in part on the presence of this grass. The first of these is
characterized by having deep channels, large tidal prism, perennial ocean
contact and well-developed, pure stands of Spartina foliosa directly above
mudflat. The second group includes those with insufficient tidal prism to
prevent seasonal or long-term closure of their ocean inlets. Invariably,
according to Macdonald (1977), Spartina foliosa is absent from the second
group. The results of this investigation do, for the most part, support
55

-------
Macdonald's observation; vigorous stands of Spartina foliosa were present at
Newport and Sweetwater; Sparti na foliosa was absent at Los Penasquitos. But,
presumably, the tidal prism at Los Penasquitos was once greater for Purer
(1942) reported not only the' presence of Sparti na foliosa there, but that it
was. more luxuriant than elsewhere, twice as tall, greener and stiffer and less
subject to being matted, and becoming blown down. The restricted distribution
of Spartina foliosa at Mugu Lagoon where tidal fluctuation is reduced (Warme
1971), and its absence from diked marsh at La Ballona Creek (Clark 1979),
lends further support, to the Macdonald (1977) model. The occurrence of
Spartina foliosa at Bolsa where tidal fluctuation has not been permitted since
1899 is, therefore, difficult to explain. Perhaps the unique environment
created by artifical removal of tides is a factor. Yet, because the salinity
regime and soil alkalinity at BB-3, 4, 5, where: this grass was sampled were
characteristic of sea water, and because elevations there were well below MHW,
it is likely that some sea water inflow through the permeable beach sands
occurred and thus permitted Spartina, which was probably present in the bay
before 1899, to persist. The answer to this question, however, may never be
known, for with the return of partial tidal fluctuation to Bolsa in November
1978, Spartina foliosa sites were drowned and the most plants deceased.
Effects of Longterm Removal of Tidal Access—Bolsa Bay
Vegetation and environmental measurements together suggest that the
absence of tidal fluctuation for 80 years strongly influenced but did not
totally alter the salt marsh system of Inner Bolsa Bay. Net production of
vascular plants, except for Spartina at.macroplot 5 which appeared to be dying
out as the study progressed, is comparable to that observed elsewhere.
Negative redox potentials and attendant anaerobisis were among the more
significant effects of diking and removal of the tides. Peat accumulations 15
to 20 cm thick in each macroplot indicated poor nutrient turnover and
restricted nutrient contribution to the adjacent mudflat and channel. Yet,
nitrogen, which has been shown to be a limiting factor in other salt marshes
(Valiela et aL 1975) did not appear to be limiting during the sampling period
at Bolsa or at the other three study sites.
Comparison of the vertical range of salt marsh vegetation at Inner Bolsa
with that of Outer Bolsa and the other southern California salt marshes
included in this study (Figure 13) identified what appears to be the major
alteration resulting from the removal of tidal flucutation. Apparently, in
the 80 year absence of periodic inundation, salt marsh plants abandoned
positions at or above MHW and re-established at anomalously low elevations.
Frankenia grandif1ora, for example, was located over 1.0 m below its normal
elevation and .25 m below the lowest Spartina foliosa or Salicornia virqinica
found elsewhere. Yet, this anomalous condition may not be due to the removal
of tidal fluctuation alone but a combination of tidal removal and subsidence
(resulting from oil or ground water withdrawls or both). Moffatt and Nichol
(1971) studied bench mark levels for the time period 1933 to 1964 and
estimated subsidence at between 23 and 46 cm. Orange County bench marks along
the west side of Inner Bolsa have been repeatedly surveyed and show continued
56

-------
loss of elevation. For example, bench mark IJ-29-68 near the sampling
transect descended by 8.4 cm between 1968. and 1976. From the available data,
a mean subsidence rate for Inner Bolsa may be estimated at about 1 cm per
year.
Subsidence, then, could account for a marshland shift downward of approx-
imately 80 cm since the removal of tidal fluctuation and, together with some
re-establishment or vegetation extension of marsh plants to lower levels, may
be responsible for the anomaly. Whatever the cause, however, it is obvious
that restoration of unrestricted tidal access to Inner Bolsa (as with a new
channel to the Pacific Ocean which is under consideration) will lead to pro-
longed inundation and destruction of some existing salt marsh.1
1 Following the construction of a parking lot for visitors and a new dike to
prevent inundation of land owned by Signal (Figure 5), partial tidal
contact as mentioned above was returned to 52 ha of Inner Bolsa by removing
flap valves on culverts through the old dike. The marsh is now (August
1979) in an advanced state of decay and, due to the restricted nature of
the culverts, water fluctuation is limited to about .5 m above -.75 MHW.
57

-------
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Bradshaw, J.S. 1968. Report on the biological and.ecological relationships in
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California Coastal Zone Conservation Commission. 1975. California coastal
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Chapman, V.J. 1976. Wet coastal formations. Elsevier Publishing Company,
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Clark, J. 1974. Coastal ecosystems. Conservation Foundation, Washington,
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Cooper, A.W; 1974. Salt marshes. Pages 55-98 m H.T. Odum et aK , editors.
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Estuarine and Coastal Marine Science 8:399-410.
Ford, R.F., A. Bradon, and M.V. Needham. 1971. Marine algae, grasses,
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Good, R.E. 1972. Salt marsh production and salinity. Bulletin Ecological
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Hesse, P.R. 1972. A textbook of soil chemical analysis. Chemical Publishing
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Hoffangle, J.,, et aK 1976. A comparative study of salt marshes in the Coos
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Hopkinson, C.S., J.G. Gosselink, and R.T. Parrondo. 1978. Above-ground
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Inman, D.L., and C.E. Nordstrom. 1978. Opening of coastal lagoons by sand
fluidization. University of California Sea Grant College Program Annual
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Kirby, C.J., and J.G. Gosselink. 1976. Primary production in a Louisiana
Gulf Coast Spartina alternif1ora marsh. Ecology 57:1052-1059.
Macdonald, K.B. 1967. Quantitative studies of salt marsh mollusc faunas from
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60

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Moffatt and Nichol, Engineers. 1971. Historic tideland investigation of
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63

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Appendix A. Macroplot living and dead standing crop biomass (g m-2).
Marsh Macroplot
Living Biomass
Dead Biomass



Harvest Session




Harvest
Session


1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
1955
1377
680
1327
2093
1725
1379
829
971
789
2056
1752
1248
1374
2
678
390
269
438
771
762
369
123
107
113
68
250
234
186
3
682
1185
650
1189
1512
1565
1534
967
1945
1616
1250
2371
1558
1230
4
555
1059
239
544
476
1136
754
114
574
297
622
593
700
641
5
462
1023
215
337
486
968
867
860
643
386
712
990
904
525
6
999
476
759
735
1313
1238
1211
700
1516
822
967
1518
780
1428
7
365
619
236
344
739
529
1461
154
510
247
563
1190
655
1148
a
489
566
181
705
1385
1095
1545
193
895
71
507
1458
987
895
9
1737
525
446
709
777
688
526
505
438
406
300
807
636
446
10
227
534
503
510
729
738
280
159
358
510
238
280
786
397
11
702
980
599
619
1158
1150
980
690
845
544
669
1018
652
1106
12
250
575
316
606
678
826
789
376
449
250
356
811
961
697
13
1008
456
857
962
1153
1391
921
667
915
771
757
1604
1496
1507
14
995
401
149
318
470
496
831
88
969
1309
213
606
453
385
15
188
85
47
195
204
293
376
157
297
167
72
164
326
232
16
660
539
426
431
322
443
387
33
92
102
194
263
167
55
17
845
1385
674
647
1186
173
1705
2097
1381
743
616
1301
1040
1435
18
845
687
254
180
896
455
807
466
1230
701
706
1360
603
664
19
715
973
894
1150
2840
2364
3430
2696
1548
2095
1269
1728
1159
2204
20
527
778
865
1511
1193
914
910
545
297
631
461
678
562
401
21
832
552
383
673
590
590
999
778
233
230
275
375
379
661
22
1072
586
564
743
1169
963
1097
743
697
486
1039
941
1095
1183
23
374
146
347
523
1419
1362
887
85
196
134
197
388
449
397
24
736
297
608
579
1012
797
724
709
326
450
138
699
375
599
25
218
900
333
1300
1902
1190
845
211
225
407
497
266
381
649
26
185
78
174
810
629
723
322
0
147
181
206
285
267
246
27
462
438
420
745
1094
1042
654
302
460
333
803
364
502
364
SRE
continued

-------
Appendix A. cont.
Marsh Macroplot
Living Biomass
Dead Biomass


1
2
Harvest Session
3 4 5
6
7
1
2
Harvest
3 4
Session
5 6
7
SRE
28
861
349
417
602
824
563
631
261
472
383
1319
796
409
552

29
45
455
99
553
474
233
120
198
300
111
378
186
478
153

30
552
589
259
1033
579
515
831
221
363
102
643
439
137
448

31
790
417
225
439
427
1023
1043
72
173
159
269
150
559
296
LPL
1
2564
960
1325
583
1623
2258
1180
1247
834
1481
466
514
532
607

2
1164
1567
1127
722
1624
1744
1203
760
892
534
447
580
814
952

3
989
2983
1459
1059
1471
1734
1738
858
830
634
176
68
185
523

4
2509
1912
1421
514
1252
1467
1665
839
1017
560
243
1123
1110
743

5
1390

1213
1317
1556
1578
1435
2838
—
2469
1156
1942
2780
1669

6
831
2607
813
1991
2119
2308
2637
2786
2111
2566
2057
2634
3447
2079

7
2880
1767
1269
1488
1158
1584
2434
839
1498
1557
1229
1091
1149
1281

8
502
274
202
213
583
663
598
4183
4552
2696
2345
4543
4749
2872

9
1181
853
467
654
1038
1625
1556
1940
2864
2133
1687
2049
2904
2556

10
2323
1228
425
1041
1040
1082
2050
1091
1677
419
475
762
1012
646

11
3303
1993
1548
2597
2965
2031
1858
806
836
1280
575
887
3713
2421

12
1269
58
802
1067
920
574
484
2197
3336
2008
2507
2159
2010
2177

13
45
10
0
24
0
1
21
1036
1508
845
1409
715
642
762

14
1164
746
945
882
393
1199
538
1688
1137
1017
964
855
1329
1262

15
3915
1931
1206
1898
1949
1787
946
1523
1901
856
1800
1458
1802
988

16
1003
625
476
411
1750
1390
1292
1501
1620
487
917
484
1402
2134

17
457
1306
1050
1180
353
808
599
1647
1603
1963
989
1367
1374
1675

18
3238
3241
703
1242
1605
2225
1916
1272
1774
830
1965
770
1535
1445

19
1308
718
780
1091
1061
1783
1684
1613
2860
1832
2142
1500
1383
2033

20
1009
1256
1003
657
729
2391
1143
1303
1029
1353
1483
657
868
1416

21
551
938
731
960
1018
1276
1214
1073
1043
824
597
798
1066
840
continued

-------
Appendix A. cont.
Marsh Macroplot
Living Biomass
Dead Biomass

1
2
Harvest Session
3 4 5
6
7
1
2
Harvest
3 4
Session
5
i
6
7
1
908
1023
414
569
1178
487
573
365
401
352
316
222
345
346
2
636
418
325
762
922
587
552
486
412
304
331
656
219
313
3
597
922
556
954
1231
1004
1056
236
491
254
403
533
329
352
4
623
382
358
620
711
667
556
349
341
325
228
1075
561
574
5
464
395
464
425
315
789
665
357
539
504
814
790
898
638
6
854
221
139
288
503
294
756
502
966
834
1125
1049
895
683
7
263
356
172
585
360
670
426
750
573
393
314
595
890
557
8
553
538
297
919
1554
795
1070
162
586
171
770
762
656
469
9
211
349
341
714
858
717
425
216
45
83
183
129
403
223
10
878
355
315
629
769
948
467
554
364
342
405
944
929
737
11
243
206
411
692
1177
814
420
147
96
106
114
456
243
271
12
493
833
718
863
662
511
377
301
491
253
327
634
713
470
13
1679
181
139
301
398
687
561
267
637
495
1134
1218
922
807
14
292
546
318
624
973
808
889
454
389
227
239
230
48
260
15
225
436
234
590
656
559
739
416
511
138
127
534
183
263
16
15
50
82
385
524
347
421
334
207
116
204
98
36
145
17
591
429
186
279
666
784
724
345
293
119
0
388
236
434
18
645
423
327
1156
1035
860
1140
321
136
141
253
457
493
435
19
257
175
94
310
520
425
212
72
196
92
171
92
142
243
20
685
221
71
379
241
377
547
326
845
738
696
1195
856
784
21
1075
449
481
447
369
683
593
473
354
331
501'
558
367
304
22
115
156
152
528
855
789
866
208
151
137
130
48
97
171
23
728
604
210
544
191
813
339
1137
1184
625
1072
598
1440
865
24
870
734
209
719
245
736
1294
570
417
145
917
355
985
1456
25
614
266
104
457
338
295
349
610
958
322
694
1491
1194
998
UNB
continued

-------
Appendix A. cont.
Marsh Macroplot
Living Biomass
Dead Biomass



Harvest Session




Harvest
Session



1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
149
1633
642
956
2059
1563
1270
927
732
143
1088
1233
873
1467
2
628
622
274
969
709
662
630
784
495
411
505
445
608
887
3
598
349
135
817
639
474
519
1046
411
320
380
1083
938
1602
4
423
28
4
61
37
203
0
1231
770
208
702
295
1096
578
5
16
50
2
0
0
0
0
62
51
2
72
16
34
62
BB

-------
Appendix B. Net Production for Plant Species in Macroplots (g m-^y-1)

Bama Crtr
Cusa
Oisp
Frgr
Juca
Lica Lose
Moli Coma
Sabi
Savi
Spfo
Suca
Trma
1



3445




131



2
137


342

88


998

121
103
3
6


1357
1



3138

391

4
107


404
2
1


2167

130

5
175



504



1435



6



1147


43

1811

33
18
7
68

47
422

10
49

2814

3
47
8
209
238
4
1349

136
204
1
2218
15
82
80
9
70


549

127
246

1804

7
99
10
40

80
206

65
122

554

33
409
11
221


504


550

1249



12
176


718

12
82

942

1
29
13

2
315
542
10
575
562

892

43
67
14









1824


15








620



16
81


12
284


366
517
5

57
17


160
415
3



3732
3


18









2659


19



6231








20
955




320

4
1319

33

21
841




862

1
482

179
197
22
980
28

698

245


1258

882

23
779

114




713
869


26
24
420
18
99
34
263
208

55
926

168
7
25
129

114

2395


272
153
345


26
3

15
5

1

632
156


792
27
375

263

845
60

355
22
98
383
25
28
28

1426
68
169
7

25
663

93

29
20


4

476

273
45


376
30
95


24
381


458
1122
545


continued

-------
Appendix B. cont.
Site	Bama Crtr Cusa Disp Frgr Juca Lica Lose Moli Coma Sabi Savi Spfo Suca Trma
LPL
UNB
1








5011
2








2088
3








3155
4








3067
5



1831




1905
6



4864




574
7








2287
8

250
1184
2962





9



3175




1994
10








3056
U








5303
12

4

4240




1176
13








1767
14








2690
15








5848
16








3224
17








2047
18








5219
19


2574





1370
20








2417
21








1582
1





357
1351


2
5


12

348
892
8
295
3
72

64
112
154
403
833

333
4
222

1

414


1
216
5
231



407



747
6









7


401



5 999


8
58

239
175
21
816
1182
1
443
9
26

43
16
470
123

466
125
10
205

1561

94



44
10
312	20
790	31
663	95
1339
142	85
511
52	235
continued

-------
Appendix B. cont.
Site	Bama Crtr Cusa Disp Frgr Juca Lica Lose Moli Coma Sabi Savi Spfo Suca Trma
11
36
162
18
554
6
103
323
9

388
12
75
780
27
96
3
1
799


261
13







2621


14
620
33
491


149
1077



15
75

184


6 4
1048



16
185
27
40

13

579
98
25

17
509

34



340
387


18
437
202

203

74
1203
55

65
19
7
13
51
151
61
40
179
49

334
20
14


32


10
1320


21
43
5 77
4
198
97

923
382

325
22
58
8
7
499
72
101
206
95

274
23







3217


24
320





3160
50
16

25
320






1969


1

74
4564







2

1178




1120



3

1452
72



1525
262


4






459
1032


5







164



-------
Appendix C.l. Salinity of Substrate at 0 to 5 cm (ppt).
Marsh
Harvest Session
Marsh
Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6
7
SRE 1
41
42


48
47
48
LPL
1

80
16
15
11
36

2
48
50

35
52
64
52

2

104
27
22
11
25

3
38
41
20

48
58
45

3

66
16
12
10


4
52
41

33
53
65
61

4

92
22

10
27

5
53
51

36
50
60
60

5
64
108
14

11


6
41
42
22
30
52
55
52

6

93
8
12
11
32

7
55
50

37
42
56
58

7
48
44
21
20
15
30

8
61
51


56
58
60

8


18




9
61
42


64
72
75

9


20




10
67
60

36
105
72
70

10

102
20

7
28

11
59
58


96
72
75

11

85
15

10
15

12
55
54


72
75


12




13


13
45
44
26

50
64


13
62
40
31
46
15
38

14
43
40
34
38
40
44
44

14

101

30
16


15
106
121
42

78
96
96

15

79
22
16
11
23

16
44
48
33

54
62
60

16

97
26
15
8


17
52
50
34

49
68
62

17

125

15
10


18
47
43
28
32
40
44
40

18
42
67
20
14
10
27
28
19
48
38
25


62


19

102
14

12


20
41
44
28
48
54
62
53

20

94

16
13


21
48
50
27
38
62
68
60

21

115

29
10


22
43
40
24
42
60
57
49









23
47
44
35
50
46
58
55
UNB
1
44
15




41
24
42
45
26
40
53
55
56

2
49
10
11

90


25
54
43
28
44
48
58
55

3
59
9
28
40
58
42
50
26
60
45
28
45
46
60
60

4
39
26
23
37
46
46
43
27
42
45
28
42
45
58
54

5
41
27
25
33
43
35
43
28
41
45
31
42
56
60
56

6
35
20
24
30
37
40
41
29
41
45
31
42
56
64
56

7

55





30
44
44
31
40
45
64
55

8
45
5
5
34
64
44
64
31
44
41
30
40
42
52
48

9
42
22
28
35
54
50
52
continued

-------
Appendix C.1. cont.
Marsh
Harvest,Session
Marsh
Harvest Session

1
2
3
4
5
6
7
UNB 10
40
18
24
32
41
44
44
11
47
22
24
37
48
50
41
12
40
22
22
34
60
50
47
13
38
29
37
36
42
38
37
14
60
44
34
64
77
76
70
15
55
44
34
55
82
85
81
15
55
44
34
55
82
85
81
16
55
43
35
56
83
91
83
17
61
57
35
48
56
68
61
18
45
41
31
42
61
51
48
19
42
25
29
40
60
63
52
20
37
37
31
35
40
40
38
21
40
28
27

41
45
38
22
41
26
24
40
52
51
47
23
36
25
22
34
37
36
36
24
40
27
30
34
40
49
42
25
37
27
30
35
40
38
35

1
2
3
4
5
6
7
1
22
7
10
7
20
28
45
2
30
10
13
13
30
34
36
3
37
29
16
27
35
48
38
4
38
33
34
35
48
45
44
5
39
33
27
47
54

44
BB

-------
Appendix C.2. Salinity of Substrate at 45 to 50 cm (ppt).
Marsh
Harvest Session
Marsh
Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6
7
SRE 1
43
42


40
47
48
LPL
1
26
50
47


25
20
2
52
53

45
44
49
60

2

60


25
25

3
49
53


42
50
51

3
40
50


21
25
12
4
55
50
50

47
55
55

4

51
44

20

20
5
55
50

49
48
47
48

5
39
70


21

25
6
63
44


42
50
54

6

71
32

17


7
57
53
44

36
43
61

7
26
81
41
22
25
10

8
70
59
44

36
51
56

8

64





9
77
62
54
42
54
60
66

9







10
71
72


61
61


10

64





11
93
70


55
61
62

11

75
41




12
67
68

70
60
64


12







13
60
50


36
49
62

13
55
51

36
44
54
60
14
54
42
42
35
38
40
40

14
56
55





15
95
102
102
98
82
104
105

15
24
55

14

28
22
16
50
61
49
44
49
58
60

16

58



52
68
17
53
40
47

39
60
55

17

66



55
62
18
44
40

35
36
40
40

18
28
37
55




19
50
38
30
27
44
42
48

19

58





20
40
50
42
49
45
46
49

20

63



55

21
42
54
46
44
45
58
52

21

69



54
64
22
50
50
35
45
42
48
52









23
58
48
53
36
49
51
61
UNB
1
52
37
3



48
24
55
51
42
38
38
50
55

2
48
41
22

30
40
48
25
45
48
41
40
42
62
55

3
44
36
21
25
32
36
45
26
45
50
45
48
48
58
62

4
44
37
42
32
35
40
46
27
46
53
37
42
40
53
56

5
43
36
32
30
32
39
40
28
48
39
44
44
42
48
48

6
36
32
33
42
36
36
48
29
60
48
39
42
43
57
58

7
49
32
4



50
30
48
46
36
42
38
62
54

8
54
39
18
27
22
43
34
31
42
42
37
40
32
41
42

9
49
37
34
32
48
59
55
continued

-------
Appendix C.2. cont.
^arSli	Harvest Session	Marsh	Harvest Session

1
2
3
4
5
6
7
UNB 10
40
37
34
32
33
42
44
11
45
37
33

44
55
52
12
40
33
25
36
45
50
48
13
38
37
34

37
40
35
14
67
65
69


64
68
15
72
67
70

78
60
65
16
63
65
63
62

66
60
17
53
68
56


64
62
18
51
52
46
45
44
48
44
19
60
51
42
54

58
62
20
38
38
39

40
34
30
21
43
34
26


50
45
22
44
41
40
32
40
43
46
23
35
35
28
32
35
34
37
24
38
35
36
32
36
40
48
25
36
35
29
30
38
34


1
2
3
4
5
6
7
1
22
22
19
22

20
25
2

20
27
29
31
35
36
3
34
31
35
35
41
35
29
4
41
34
39
35
45
32
42
5
36
36
40
36
48
47
38
BB

-------
Appendix C.3. Salinity of Substrate Free-water (ppt),
Harvest Session	Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6
7
SRE 1
40
47
20

48
46
50
LPL
1
32
50
33
9



2
55
50
34
47
44
55
60

2

54
40
12
15


3
48
40
28

47
48
50

3
56
26
6
19
26


4
52
43
38

40
50
50

4

51
33
16
10
27

5
46
45
30
34
42
48
50

5

56
20
10
10
20

6
43
40
24


49
50

6

61
28
16
6


7
52
44
29

40
47
47

7

35
32
16
15
26
20
8
54
50
36

45
58
60

8


24




9
62
45
42

54
65
66

9


29
25



10
57
61
26

60
68
62

10

54

16
15

65
11
58
52
26


72
65

11

65
20
10
16
20
46
12
61
54
37


70
54

12


31




13
35
40
22


47
52

13

51
35
5
10
55
62
14
37
40
33

36
40
40

14

51
24
22
18
48

15
94
72
103



102

15
32
45
33
8
13
16
34
16
48
48
44

47
54
58

16

54
41
28
16
60
70
17
40
43


37



17
62
57
34
15
18
55
62
18
38
37

31

40
40

18
25
35
23
3
25
16

19
45
37
27



42

19

55
28
25
20
25

20
55
44
27
38
51
54
52

20

54
26
12
17
52

21
55
45
31
38
50
58
60

21

61
32
8
22
60

22
50
39
28
42
40
48
50









23
50
44
30
35
45
57
60
UNB
1

3
3



34
24
52
44
27
37
48
52
54

2
46
10
12


48
48
25
52
42
30

45
55
56

3
39
14
18
23

44
48
26
50
43
32

50
57
55

4
42
39
30
30

40
44
27
50
43
30

43
54
52

5
42
36
25
28

38
42
28
43
45
42

38
42
45

6
35
19
22
30
34
36
34
29
48
43
30

46
53
50

7

5
3




30
50
40
38

46
54
52

8
40
24
11
11

45

31
42
37
30
34
40
40
42

9
45
39
32
32

50
52
continued

-------
Appendix C.3. cont.
Marsh	Harvest Session	Marsh	Harvest Session

1
2
3
4
5
6
7
UNB 10
38
33
25
26
35
38
40
11

34
28
30
50
38
44
12
34
28
23
31

42

13
35
23
22
32
34
34
34
14
61
40
45
48

70
71
15
70
57
44
50

78
74
16
70
46
61
56

68
65
17
65
56
40
44

60
65
18
49
44
37
46
45
46
50
19
41
39
36
34

50
62
20
41
30
27
34

35
28
21
38
27
22
32

36
42
22
40
30
22
35

48
45
23
33
30
23
28
41
34
34
24
37
28
22
28

38
38
25
36
33
21
25
31
35
30

1
2
3
4
5
6
7
1
31
13
14
7
15
20
25
2
37
9
16
18
29
30
32
3
31
26
16
26
40
41
40
4
37
26
25
35
48
45
47
5
37
26
9
41
42
50
42
BB

-------
Appendix C.4. Reaction (pH) of Substrate Free-Water by Harvest Session (Assume One Decimal Place).
Harvest Session	M . .	Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6 7
SRE 1
62
68
70

67
66
70
LPL
1

68
67
67


2
63
66
66
66
64
66
65

2

73
69
69
67

3
56
60
62

62
62
58

3

65
63
68
63
65
4
59
60
63

60
61
62

4

66
66
66
67
68
5
61
67
71
73
68
68
66

5

64
67
69
66
72
6
61
64
64


63
60

6

66
67
68
67

7
63
62
65

64
62
62

7

59
60
63
64
69
8
60
65
64

64
66
62

8

72




9
61
66
64

61
67
62

9


70
70


10
64
65
67



62

10

63
62
70
65

11
63
67
70


66
64

11

64
64
69
63
66 63
12
69
68
67


66
64

12


70



13
69
65
72


62
64

13

68
67
70
72

14
63
69
65

65
65
63

14

67
67
68
61
70
15
64
76
67





15

64
63
63
66
68
16
70
60
61

61
61
59

16

70
65
68
64
67 76
17
62
55


69



17
73
67
69
66
69
67
18
64
62

70

66
64

18

63
67
71
62
63
19
72
74
76


70
72

19

70
67
68
63
78
20
70
67
72
62
69
66
69

20

74
68
69
66

21
67
66
70
68
67
67
68

21

73
71
69
67
73
22
69
69
73
78
66
66
70








23
68
67
79
70
66
68
70
UNB
1

88
85



24
68
67
69

68
67
71

2
75
77
72


72 71
25
65
60
69

66
65
68

3
74
74
72
69

70
26
63
61
64

63
61
63

4
63
61
64
62

61 62
27
61
57
63

64
60
63

5
74
61
65
61

62 60
28
60
59
59

60
58
60

6
67
65
66
63
68
66 65
29
60
60
62

60
59
60

7

82
78



30
60
55
66

60
57
62

8
70
74
73
70

69
31
63
59
66
69
65
67
64

9
62
63
64
67

62 62
continued

-------
Appendix C.4. cont.
Marsh
Harvest Session
Marsh.
Harvest Session

1
2
3
4
5
6
7
UNB 10
62
62
63
61
68
59
70
11

63
62
62

66

12
65
66
67
65

64

13
64
69
68
68
68
70
69
14
61
64
63
66

63
61
15
60
60
64
61

61
57
16
60
60
62
61

62
65
17
67
61
68
63

59
52
18
57
57
62
55
59
60
57
19
63
61
63
63

63
63
20
67
66
67
66
69
65
72
21
61
64
63
63

66
61
22
61
63
62
61

62
68
23
68
64
72
64

65
65
24
61
64
75
80

64
62
25
68
68
68
71
66
65
64

1
2
3
4
5
6
7
1
74
70
72
70
69
72
68
2
77
77
74
69
69
71
71
3
79
73
75
70
68
72
72
4
71
73
69
70
73
68
72
5
80
78
76
72
74
72
74
BB

-------
Appendix C.5. Ammonia in Substrate Free-Water (10-5 M).
Marsh	Harvest Session	Marsh	Harvest Session
1 2 3 4 5 67	1 2.3 4 5 6 7
SRE 1	9	1	24	9	60 LPL 1	11	4	7
2	15	1	3	9	5	9	2	4	1	7 25
3	4	1	15	6	29	3	9	1	5 54 19
4	12	17	2	10	9	66	4	4	1	7 41 41
5	23	5	22 21	34	25	5	4	1	6 22 23
6	17	1	7	15	6	29	1	8 64
7	6	15	1	10	20	7	11	3	19 55 230
8	11	1	20	20	12	8	2
9	18	1	41	6	13	9	2	10
10	8	3	6	8	10	42	2	17 39
11	5	1	10	14	11	6	2	6 20 52 27
12	2	9	14	12	1
13	13	3	7	10	13	10	4	20 54
14	36	111	11	5	20	14	2	3	6 18 18
15	13	2	15	1	2	8 24 35
16	15	1	11	15	7	16	6	3	5 39 33
17	24	14	18	17	8	3	5 41 42
18	10	11	12	16	18	10	2	5 25 42
19	36	1	10	6	19	1	1	5 43 22
20	30	1	24 11	6	23	20	1	3	6 28
21	30	1	9	4	5	7	21	3	6	6 380 28
22	24	14	1	15 8	4	9
23	60	10	1	4 5	6	9 UNB 1	7	3
24	60	10	1	15 4	4	5	2	21 2	8 8 6
25	40	13	1	3	4	7	3	22 2	4	38	4
26	34	18	1	3	6	5	4	41 16	6	19	5 5
27	34	18	1	3	9	6	5	16 32	3	12	17 6
28	5	12	1	3	8	9	6	580 440	105	66 320 102 25
29	19	17	1	344	7	2	25
30	7	17	1	3	3	7	8	18 2	4	10	5
31	9	17	1	19 20	290	7	9	12 3	6	14	12 6
continued

-------
Appendix C.5. cont.
|Yjars^	Harvest Session	Marsh	Harvest Session

1
2
3
4
5
6
7
UNB 10
12
4
3
15
18
9
6
11

7
4
9
16
26

12
24
3
3
18

36

13
105
42
26
132
360
640
77
14
96
7
3
47

6
18
15
45
12
15
55

8
20
16
105
26
88
75

65
59
17
100
3
210
134

35
6
18
22
5
4
6
30
17
4
19
11
4
3
56

20
8
20
25
26
21
32
54
5
6
21
26
5
7
19

7
3
22
15
3
3
24

6
8
23
108
8
13
33
130
66
26
24
45
6
5
30

6
8
25
120
13
6
14
54
49
87

1
2
3
4
5
6
7
1
43
30
15
8
42
24
67
2
39
5
3
4
7
32
550
3
72
3
3
6
10
56
94
4
730
4
36
88
64
860
610
5
75
6
11
78
17
690
95
BB

-------
Appendix C.6. Redox Potential (Eh*mV) for Substrate Free-Water.
Marsh
Harvest Session
Marsh
Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6
7
SRE 1
407

382

497
422
367
LPL
1

427
312
307



2
447

427
367
492
417
447

2

437
357
352
262


3
317

357

482
427
407

3

442
302
412
272
252

4
297

407

427
427
247

4

437
292
402
232
282

5
372

407
317
442
397
407

5

367
292
422
237
289

6
412

377


427
442

6

337
322
417
327


7
387

397

467
397
432

7

437
282
352
182
347
377
8
427

432

472
402
397

8


317




9
447

397

512
312
387

9


222
447



10
457

432



322

10

387
122
392
162


11
407

407


407
342

11

372
232
362
167
317
242
12


427


417
342

12


337




13
392

407


412
427

13

407
342
392
227


14
247

297

462
317
392

14

327
332
407
272
187

15


427





15

327
312
417
187
247

16
392

367

482
417
302

16

397
237
372
257
237
347
17
447



457



17
422
297
227
372
142
267

18
377


357

327
257

18
342
367
482
462
292
292

19
362

347


302
397

19

392
322
382
312
272

20
372

407
302
472
332
377

20

392
262
392
287


21
277

422
297
457
347
377

21

302
472
242
292
317

22
382

407
292
462
352
407









23
407

392
302
-18
367
347
UNB
1

422
382




24
447

422

467
372
392

2
342
357
337


387
247
25
447

427

467
402
297

3
317
357
262
377

372

26
397

447

477
392
307

4
347
360
247
397

367
267
27
397

442

477
87
347

5
262
364
187
397

177
397
28
442

447

467
467
417

6
-78
382
82
407
-113
-43
-43
29
327

447

472
387
427

7

512
127




30
432

442

472
387
402

8
297
462
337


412

31
197

307
257
472
352
359

9
197
392
362
387

259
292
continued

-------
Appendix C.6. cont.
Marsh	Harvest Session	Marsh	Harvest Session

1
2
3
4
5
6
7
UNB 10
337
537
337
357
217
367
297
11

472
327
447
277
217

12
222
547
232
337

352

13
-63
442
-98
-23
-73
-38
-98
14
237
432
267
277

232
397
15
227
392
357
397

357
267
16
272
338
182
407

357
367
17
177
381
-98
257

259
342
18
347
412
172
337
257
397
257
19
217
376
212
407

447
387
20
-38
417
11
397
147
357
262
21
137
362
167
347

377
367
22
192
422
197
397

382
337
23
67
384
237
297
97
47
72
24
212
382
247
267

422
287
25
-43
369
237
182
219
307
267

1
2
3
4
5
6
7
1
147
342
127
87
277
122
357
2
212
289
22
137
57
42
322
3
47
288
-33
37
27
-23
12
4
-88
299
-126
-63
-43
-58
-73
5
7
317
7
-53
-53
-78
-53
BB

-------
Appendix C.7. Water Content (Percent) of Substrate at 0-5cm.
Marsh
Harvest Session
Marsh
Harvest Session

1
2
3
4
5
6
7


1
2
3
4
5
6
7
1

52
39
33
38
39
37
LPL
13
50
48
49
59
53
42
38
2
65
59
64
48
66
47
41

14
40
41
52
51
50
41
35
3
57
63
58
46
42
48
38

15
49
49
54
54
54
53
45
4
59
64
64
63
59
62
54

16
35
40
51
54-
51
39
31
5
56
53
53
56-
53
54
47

17
32
39
45
57
53
36
32
6
75
64
51
45
53
42
46

18
50
45
55
55
55
50
44
7
56
47
50
40
54
52
30

19
44
43
56
53
58
41'
35
8
42
49
42

35
38
42

20
32
34
50"
55
47
35
28
9
48
49
44
38
42
35
37

21
38
43
42
44
42
36
32
10
41
42
41
40
33
38
36









11
41
42
43
43
37
33
39
UNB
1
8
21
14
8
1
9
5
12
51
45
41
37
37
39
34

2
15
21
20
18
11
19
11
13
47
39
40
30
31
35
33

3
28
32
29
28
21
30
22
14

45

45
44
44
43

4
69
72
75
72-
69
69-
71
15

38
31
27
25
28
31

5
68
71
70
58
67
66
63
16
59
63
62
59
55
50
61

6
65
68
68
67
65
68
62
17
41
41
44
37
46
42
40

7

20
12
4
0
9
1"
18
47
47
49
47
46
45
48

8

29
32
25
19
30
22
19
38
43
32
40
30
31
37

9

76
72
68
65
74
69
20
64
61
55
51
65
52
50

10

73
65
71
67
66
64
21
51
48
49
48
58
49
61

11

77
71
74
68
68
68
22

57
59
47
47
52
53

12

57
53
64
43
53
45
23
66
64
69
63
69
68
45

13

70
64
43
62
63
63
24
70
74
53
56
60
56
51

14
69
74
71
43
68
71
69
25
54
64
64
69
66
66
65

15
73
76
75
75
68
72
67
26
51
67
67
68
63
62
64

16
75
76
76
75
69
70
69
27
64
61
65
61
63
41
61

17
65
73
72
75
65
69
69
28
55
59
61
59
56
55
55

18
72
77
80
78
72
77
78
29
56
59
57
58
58
56
55

19
69
73
71
72
65
68
67
30
44
57
52
56
52
52
50

20
69
68
69
70
71
72
68
31
50
42
40
41
41
44
38

21
69
71
73
68
65
66
66









22
63
66
67
66
62
62
66
1
49
41
63
63
69
57
33

23
62
63
64-
62
56
61
59
2
46
42
55
67
57
50
39

24
52
58
48
57
47
51
44
3
47
45
61
55
55
56
41

25
57
63
57
58
56
53
56
4
59
51
68
59
60
48
26









5
49
48
53
54
62
51
38
BB
1
42
50
37
78
64
46
51
6
51
56
63
54
57
47
43

2
78
80
83
73
60
73
78
7
51
57
57
61
61
55
52

3
85
86
89
77
86
85
86
8
27
13
40
35
33
22
20

4
74
80
82

72
79
80
9

28
41
33
34
20
17

5
76
65
82
89
79
75
77
10

55
60
58
57
50
44









11
54
55
58
66
66
61
49









12
27
22
33
37
37
21
10









82

-------
Appendix C.8. Water Content (Percent) of Substrate at 45-50 cm.
Harvest Session	Marsh	Harvest Session


1
2
3
4
5
6
7


1
2
3
4
5
6
7
SRE
1

34
30
26
23
21
35
LPL
11
27
28
27
37
30
28
27

2
45
48
47
47
47
48
53

12
27
28
31
25
27
28
25

3
46
47
47
42
42
42
41

13
32
36
30
37
29
33
27

4
48
62
51
40.
56
47
29

14
29
30
18
33
34
28
29

5
50
56
52
55
54
51
56

15
30
31
31
35
34
25
33

6
30
34
37
40
30
3 V
32

16
28
28
27
31
30
30
27

7
32
36
32
46
31
31
31

17
27
28
25
28
29
27
27

8
30
30
31
20
28
29
56

18
40
40
40
43
42
39
40

9
33
33
34
30
32
28
30

19
21
27
21
38
23
26
28

10
32
31
31
27
29
28
28

20
22
29
27
28
30
45
29

11
25
32
26
26
27
28
30

21
27
21
26
31
29
29
30

12
27
26
27
25
24
27
24










13.
26
24
23
20
24
26
27
UNB
1
16
23
22
19
16
22
19

14
34
38
26
54
38
40
40

2
25
23
25
25
23
36
23

15

23
22
23
22
19
22

3
23
29
55
24
57
60
52

16
35
35
32
32
34
37
36

4
46.
45
48
59
47
44
30

17
42
47
33
33
43
46
42

5
61
51
50
70
67
29
45

18
47
45
47
47
47
44
57

6
52
56
54
54
52
55
55

19

44
41
40
45
41
39

7

20
22
10
19
20
18

20
56
57
59
57
56
56
54

8

32
65
25
56
62
61

21
53
56
54
45
56
47
52

9

34
24
27
29
23
24

22
49
50
50
49
49
48
47

10

29
26
31
25
30
22

23
51
50
58
50
52
36
67

11

22
23
23
23
29
21

24
53
52
65
36
35
29
37

12
23
27
33

21
23
20

25
65
54
54
52
48
53
51

13

42
39
24
39
29
32

26
68
55
47
53
49
48
51

14
40
22
23
22
31

43

27
50
55
55
52
49
67
49

15
20
21
20
32
21
21
20

28
32
54
52
50
54
51
50

16
57
21
29
39
21
22
20

29
37
44
39
44
51
41
48

17
21
47

24
33
20
20

30
50
38
45
40
44
38
45

18
35
38
34
36
26
29
25

31
38
56
56
42
47
38
42

19
23
21
21
20
22
21
19










20
22
26
26
30
23
24
24
LPL
1
19
'
21
30
20
22
20

21
28
23
22
26
20
20
19

2
19
17
19
22
21
25
19

22
44
42
39
45
34
30
35

3
23
26
30
29
29
33
27

23
40
32
40
35
25
28
27

4
27
37.
36
45
31
35
31

24
51
56
46
54
39
43
54

5
36
37
40
42
40
42
33

25
28
33
31
34
30
31
31

6
22
38
27
38
32
35
32










7
42
45
44
46
47
46
46
BB
1
23
25
27
28
23
24
22

8
15
19
19
23
22
17
12

2
18
22
22
22
48
23
23

9

21
23
25
22
22


3
39
36
20
23

21
36

10
32

31
32
31
32
28

4
32
20
35
28
24
22
32










5
37
19
25
21
23
41
42
83

-------
Appendix C.9. Temperature (°G) of Substrate at 0-5 cm.
Marsh,	Harvest Session
1
21.5
2
22.0
3.
21.5
4
21.5
5
22.5
6
22.0
7
21.5
8
23.0
9
22.0
10
18.5
11
22.0
12
23.0
13
21.5
14
23.0
15
23.3
16
23.0
17
23.5
18
22.5
19
22.5
20
23.0
21
22.5
22
21.5
23
21.5
24
22.5
25
22.5
26
23.5
27
22.5
28
22.0
29
23.0
30
21.5
31
22.0
1
19.5
2
18.5
3
18.5
4
18.5
5
18.5
6
18.5
7
18.2
8

9
18.0
10
18.0
16.5
11.7
16.5
11.1
17.0
11.1
17.0
11.7
17.5
11.1
16.5
11.1
16.5
11.1
16.5
11.1
16.5
11.1
16.5
11.7
16.0
11.1
17.5
11.7
16.5
11.7
16.5
12.8
17.0
12.2
17.5
11.7
16.5
11.7
17.5
12.2
16.5
11.7
16.5
11.1
16.5
12.2
15.5
11.7
16.0
12.2
16.5.
11.7
16.5
11.7
16.5
12.8
16.5
12.8.
16.5
12.2
17.0
12.8
16.5
11.7
17.5
12.2
13.9
11.1
13.3
11.1
13.3
10.6
1.3.3
11.1
12.8
10.6
13.3
10.6
13.3
11.1
13.3
11.1
13.9
10.6
14.4
11.1
15.0
17.2
15.6
17.8
15.0
17.8
15.0
17.8
15.0
18.3
14.4
17.2
15.6
17.8
13.9
18.9
14.4
21.1
14.4
19.4
14.4
18.3
15.0
19.4
14.4
18.3
15.6
20.0
16.7
23.3
15.6
20.0
14.4
18.3
14.4
20.0
13.9
16.7
15.0
17.8
13.9
18.3
13.9
17.8
14.4
18.9
14.4
18.3
13.9
18.3
15.6
19.4
14.4
18.9
14.4
17.8
16.7
20.0
14.4
18.9
16.7
20.6
13.9
18.9
13.9
16.7
15.0
18.1
13.9
17.0
13.3
16.1
13.3
15.9
14.4
17.0
13.9
17.5
13.9
17.2
14.4
17.2
17.8
16.7
18.9
18.3
18.3
17.2
18.9
17.2
19.4
17.8
17.8
17.2
18.9
17.8
18.3
17.8
19.4
18.9
19.4
18.9
18.9
17.8
19.4
18.9
17.2
17.8
19.4
18.3
22.8
20.0
20.0
18.9
19.4
16.7
19.4
18.3
17.2
17.2
18.3
17.8
19.4
20.0
18.9
17.8
19.4
18.9
18.9
18.9
18.9
18.3
20.0
20.0
18.9
18.9
18.9
18.3
21.1
20.6
20.6
18.9
21.1
20.0
17.8
17.2
17.8
16.1
17.8
17.2
19.4
18.3
16.9
16.1
16.7
15.0
17.5
14.4
17.2
14.4
17.8
17.2
18.3
16.7
84
continued

-------
Appendix C.9. cont.
Marsh	Harvest Session


1
2
3
4
5
6
7
LPL
n
18.0
14.4
11.1
14.4
17.2
18.3
16.7

12
18.0
10.6
12.2
14.4
18.9
20.0
20.6

13
16.5
8.9
12.8
15.6
18.9
22.2
18.3

14
17.5
9.4
11.1
13.3
17.2
19.1
16.1

15
16.5
9.4
11.7
13.3
17.2
17.5
13.9

16
17.5
12.8
10.0
13.9
17.8
20.9
16.7

17
17.5
11.1
9.4
13.3
17.8
20.9
15.6

18
17.0
11.1
8.3
12.2
18.3
18.9
14.4

19
17.5.
11.1
11.1
13.3
19.4
18.0
14.4

20
17.0
10.0
11.1
13.9
18.3
19.4
16.1

21
17.0
10.0
9.4
14.4
18.3
17.8
14.4
UNB
1
22.0
13.3
11.7
13.9
22.2
19.4
19.4

2
20.0
12.2
11.7
13.9
20.0
20.3
17.2

3
20.0
12.8
11-. 7
13.9
20.0
19.7
17.2

4
20.0
13.3
12.8
14.7
18.9
18.0
17.2

5
19.0
1.2.8
12.2
15.3
18.9
19.4
16.7

6
19.0
13.3
13.3
15.3
19.4
19.7
16.7

7
19.0
12.2
11.7
15.0
20.6
23.3
27.8

8
18.0
12.8
11.7
13.3'
17.8
17.8
17.2

9
19.0
12.2
12.2
14.4
18.3
19.2
18.3

10
18.0
12.2
11.7
13.9
17.2
16.7
16.1

11
21.0
13.9
13.9
14.4
18.3
17.8
17.2

12
19.0
14.4
13.9
14.7
18.3
17.8
15.6

13
19.0
13.9
13.3
15.6
19.4
20.0
17.2

14
22.5
12.2
13.3
15.0
20.6
19.4
16.7

15
22.0
12.2
12.8
14.4
20.6
20.6
17.2

16
22.5
11.7
14.4
15.6
19.4
21.7
18.3

17
20.5
12.8
13.9
16.1
19.4
20.3
17.8

18
18.5
11.7
14.4
14.4
18.9
17.8
17.2

19
23.0
12.2
13.3
16.1
22.8
18.9
17.2

20
18.5
12.8
13.9
16.1
21.7
17.5
17.2

21
19.0
12.2
12.8
14.4
20.9
17.8
16.7

22
19.5
12.8
13.9
16.1
20.6
18.0
16.7

23
17.5
13.3
13.9
15.0
19.4
17.5
16.1

24
18.0
12.2
12.8
14.4
20.0
16.7
15.6

25
18.5
13.3
14.4
15.0
20.0
16.7
16.1
BB
1
14.5
12.2
12.2
15.0
17.2
17.2
17.2

2
14.0
11.7
12.2
15.0
16.7
16.9*
17.2

3
15.0
12.8
12.8
18.9
17.8
17.8
17.8

4
17.0
13.3
13.9
16.7
18.9
18.9
19.4

5
15.5
13.9
14.4
20.0
20.0
18.3
20.0
85

-------
Appendix C.10. Temperature (°C) of Substrate at 45-50 cm.
Marsh	Harvest Session
1
18.9
2
19.4
3
19.4
4
19.4
5
19.4
6
19.4
7
19.4
8
18.9
9
19.4
10
19.4
11
19.4
12
20.0
13
20.0
14
20.0
15
20,6
16
20.6
17
19.4
18
20.0
19
19.4
20
19.4
21
20.0
22
19.4
23
19.4
24
19.4
25
20.0
26
20.6
27
20.0
28
19.4
29
21.1
30
20.6
1
17.8
2
16.7
3
17.8
4
17.8
5
17.8
6
17.8
7
17.2
8

9
18.3
10
16.7
11
16.7
13.9
12.8
13.9.
13.3
13.9
12.8
13.9
12.8
15.0
12.8
14.7
12.8
14.7
12.8
14.7
12.8
14.7
12.8
14.7
12.8
14.7
12.2
15.0
12.8
15.0
12.8
15.6
13.9
15.3
12.8
15.3
13.3
15.0
12.8
15.6
13.9
13.9
12.8
13.9
12.8
14.4
12.8
14.4
12.8
13.9
13.3
14.4
12.8
14.4
13.3
15.6
13.9
13.9
13.3
14.4
13.3
15.6
13.9
15.0
13.9
13.9
12.2
13.0
11.7
14.4
12.8
13.9
12.2
13.9
12.2
14.4
12.2
13.9
12.2
14.4
11.7
13.3
11.7
13.9
12.8
13.9
12.8
13.9
16.7
15.0
17.2
14.4
17.2
14.4
17.8
11.4
17.8
13.9
17.2
14.4
17.8
14.4
18.3
14.4
17.8
15.0
18.3
14.4
17.2
15.0
18.3
14.4
17.2
16.1
18.9
16.7
23.3
15.0
18.3
15.0
17.2
15.6
17.8
13.3
15.0
13.3
15.0
15.0
17.2
14.4
16.7
15.0
17.8
15.0
17.8
13.9
17.2
15.6
18.3
15.6
17.8
14.4
17.2
16.7
18.3
15.6
19.4
13.9
18.3
13.9
17.0
15.0
17.5
13.9
16.7
13.3
16.1
13.3
16.1
13.9
17.2
13.9
16.7
13.9
16.7
13.9
17.0
14.4
18.1
17.2
17.8
18.3
18.9
16.7
17.8
18.3
18.9
17.2
18.3
16,1
17.2
17.8
18.9
18.3
18.3
18.3
18.9
18.9
18.9
18.3
18.3
18.9
19.4
17.8
17.8
18.9
18.9
22.2
20.6
18.3
18.3
18.3
18.3
17.8
18.3
15.6
17.2
15.6
17.2
16.7
17.2
16.7
17.8
18.3
18.9
17.2
18.3
17.8
17.8
18.3
20.0
17.8
18.3
17.8
18.3
18.9
20.0
18.9
19.4
16.9
17.2
16.9
16.7
17.5
16.7
16.7
15.6
15.6
15.6
15.6
15.6
17.2
16.1
17.0
16.7
17.0
16.7
16.9
16.7
17.2
17.2
continued
86

-------
Appendix C.10. cont.
Marsh	Harvest. Session
12
16.7
13.3
12.2
15.0
17.8

17.8
13
17.8
12.8
12.8
15.0
18.9
18.6
17.8
14
17.2
12.2
12.2
13.9
17.2
17.8
16.7
15
17.8
12.8
12.2
13.9
18.9
16.7
16.7
16
17.2
12.8
12.8
14.4
17.8
17.8
18.3
17
16.7
12.2
12.2
13.9
17.2
17.8
16.7
18
16.7
12.2
11.7
13.3
17.2
17.0
17.2
19
17.2
12.8
11.7
13.9
17.8
16.7
16.1
20
16.7
11.7
11.7
13.3
17.2
17.8
17.2
21
17.8
12.2
11.7
13.9
16.7
16.7
16.1
1
18.3
19.8
12.8
15.0
19.4
18.3
17.8
2
16.7
12.2
12.2
15.0
19.4
18.0
17.2
3
16.7
13.9
12.8
14.4
17.2
17.8
17.2
4
16.7
13.9
12.8
14.7
17.8
17.5
17.2
5
16.7
13.9
12.8
15.0
17.0
17.2
17.2
6
16.7
13.3
13.3
15.0
18.9
17.8
16.7
7
18.3
12.8
12.2
15.6
20.6
19.7
18.9
8
16.7
12.2
12.2
15.0
18.3
17.8
17.2
9
17.8
13.3
12.8
15.0
17.8
18.0
18.3
10
16.1
12.8
12.2
13.9
17.2
16.4
16.1
IT
16.1
12.8
12.2
13.9
17.2
16.4
16.1
12
16.7
13.3
12.8
14.4
18.3
16.9
16.7
13
16.7
13.9
13.3
15.3
18.3
17.8
17.2
14
17.8.
13.9
13.3
15.6
18.9
18.3
18.3
15
17.8
13.9
13.3
16.1
20.0
19.2
18.3
16
17.8
13.9
12.8
16.1
20.0
19.2
18.9
17
17.8
13.9
13.3
16.7
19.4
19.7
18.3
18
17.2
13.3
13.9
15.0
17.2
17.2
17.2
19
17.8
13.3
12.8
15.6
18.9
18.9
18.3
20
17.8
13.9
13.9
15.6
18.9
17.5
17.2
21
17.9
13.3
13.3
15.0
18.3
17.8
17.2
22
16.7
13.9
13.9
15.6
18.3
17.8
17.2
23
16.7
14.4
13.9
15.0
17.8
17.2
16.7
24
16.7
14.4
13.3
13.9
17.2
16.9
16.7
25
16.7
14.4
13.9
15.0
17.8
16.9
16.7
1
14.4
12.8
12.2
14.4
17.2
17.2
17.2
2
14.4;
12.8
12.8
14.4
17.2
16.7
16.7
3
15.6
13.9
13.3
15.0
17.2
17.2
17.2
4
16.7
14.4
13.9
15.6
18.9
18.0
18.9
5
17.8
14.4
15.0
16.1
18.9
18.3
18.9
87

-------
Appendix; D. Macroplot Elevation and Habitat Type. Habitat as Follows:
Fore- Levee Slope (1), Levee Crest (2), Back Levee SI0De C3").
Back Levee Depression (4), Slope Below- Upl-and (5-).,. Up-Vand
Transition (6), Pan (7).
Marsh
SRE
LPL

ETevati on
Habitat
Marsh
Elevation
Habitat
1
. 34a
6-
LPL 12
.51
6
2
.15
4
13
.21
1
3
.35
2
14
.29
3
4
.42
2
15
.27
2
5
.08
2
16
.15
4
6
.33
2
17
.17
4
7
.22
4
.8
.31
2
8
.39
3
19
.33
2
9
.34
3
20
.25
3
10
.38
3
21
.25
3
11
.37
3



12
.35
3
UNB 1
1.05
6
13
.49
2
2
.84
5
14
-.30
1
3
.69
5.
15
.52
7
4
.44
¦T
16
.13.
4
5
.40
1
17
.33
2
6
.27
1
18
-.27
1
7
1.17
6
19:
.61
6
8
.77
5
20
.27
5
9
.51
3
21
.33
5
10
.47
3
22
.41
5.
11
.49
3
23
.20
4
12
.55
2
24
.24
4
13
.18
1
25
.18
4
14
.70
4
26
.15
4
15
.70
4
27
.11
3
16
.70
4
28
.14
3
17
.62
4
29
.14
4
18
.65
4
30
.11
3
19
.59
4
31
-.17
¦1
20
.33
1



21
.56
4
1
.17
3
22
.54
3
2
.19
3
23
.31
3
3
.08
3
24
.53
2
4
.17
3
25
.22
1
5
.22
3



6
.28
3
BB 1
-.57
6
7
.25
2
2
-.87
5
8
.59
6
3
-.96
5
9
.57
6
4
-1.07
1
10
.24
6
5
-1.12
1
11
.24
2



aMeters; reference is local MHW.
88

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