United States
Environmental Protectbn
Agency
Office of Research and
Development
Washington, DC 20460
EPA/620/R-01/001h
November, 2001
ยป EPA Coastal Communications
REMOTE SENSIN6 OF COASTAL AND
ESTUARINE WATERS AND HABITATS
Background
Remote sensing is the science of acquiring information about the Earth's surface by
sensing and recording reflected or emitted energy. The U.S. EPA's Office of Research and
Development's National Health and Environmental Effects Research Laboratory (NHEERL)
is conducting research in the use of aerial and satellite imagery to remotely collect
information on the environmental condition of coastal and estuarine habitats. Conventional
sea or ground-level sampling will be augmented by this remotely-sensed data to provide
synoptic information on water quality indicators [e.g., chlorophyll a and total suspended
solids (TSS)] and habitat characteristics at smaller spatial scales and shorter time
intervals. Incorporating these data into environmental assessments will assist the
States and Tribes in developing a better understanding of the effects of natural and
anthropogenic stressors on coastal and estuarine habitats across a variety of temporal
and spatial scales.
Approaches
Two of NHEERL's Ecology Divisions,
the Atlantic Ecology Division (AED),
and the Western Ecology Division
(WED) have developed remote sensing
research programs. The AED is
utilizing two approaches to under-
stand stressor effects in coastal
areas. Global scale, multi-year
satellite (AVHRR) images were
reprocessed using visualization
software, and subsequently integrated
with data from the Texas Water
Development Board to create data
sets at weekly to monthly time scales.
These data sets related changes in
coastal vegetation greenness with
regional scale climate conditions and
watershed water management
practices (see Fig. 1). In a second
approach, bio-optical models are being developed in partnership with EPA Region I, the
University of Rhode Island, Brown University, and NOAA. These models accurately
simulate the distribution of chlorophyll a concentrations in New England estuaries from
ocean color viewed from aircraft or satellite sensors.
Fig. 1. Reprocessed Advanced Very High Resolution
Radiometer (AVHRR) sensor image of the Texas Upper
Coast and Lower Galveston Bay.
(Over)
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The WED is comparing side-
scan and sediment-penetrating
sonars, underwater video
imagery and aerial photography
for mapping benthic
invertebrate habitats (Fig. 2).
These mapping tools are
designed to assist States and
Tribes in establishing criteria
that will be protective of
these important resources.
They also support EPA's
research on determining the
effects anthropogenic
stressors may have on
estuarine habitats and food
webs. Geographic image
analysis applications of color
infrared (CIR) aerial imagery
are being developed to
interpret, classify and map intertidal submerged
aquatic vegetation (SAV; e.g., Zostera spp., eelgrass) (Fig. 3).
Because eelgrass has been
Interpolated Distributions
Fig. 2. Map ofYaquina Bay, OR showing distribution and density of
two burrowing shrimp genera & two species of the seagrass Zostera.
Remote Sensing to Classify and Map Estuarine Intertidal Vegetation
Yaquina Bay Estuary, Oregon
False Color Infrared Aerial Photo Mosaic
Geographic Image Analysis:
Habitat Classification and Delineation
Qpt Zostera marina J
^f^ Macroalgae ,;
fl^Subtidal j;f
; 3 Intertidal
0.5 0 0,5 / 1.5 2 K//omerers
Fig. 3. Digital image classification algorithms are used to
classify SAV in the Yaquina Bay Estuary, OR.
identified as critical habitat
for many estuarine species,
concerns have been raised in
the Pacific Northwest (PNW)
regarding possible negative
impacts of increasing nutrient
levels to eelgrass habitat via
the stimulus of macro algae
growth. The goal of this
research is to develop
techniques to monitor changes
in estuarine habitats at a very
high resolution (~ 0.2 m).
Further Information
For further information on the data analysis and algorithm development of the bio-optical
models or watershed analyses, contact Darryl Keith keith.darryl@epa.gov. at (401) 782-
3135 at the EPA's NHEERL Atlantic Ecology Division. The NHEERL Western Ecology
Division's contacts for estuarine habitat mapping are Ted DeWitt, dewitt.ted@epa.gov.
(541) 867-4029, and David Young, young.david@epa.gov. (541) 867-4038 at the Pacific
Coastal Ecology Branch in Newport, OR. Visit the Coastal Communications Web Site at
http://www.epa.gov/ged/crc.htm.
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