Grantee Research Project Results
2003 Progress Report: A Shallow-water Coastal Habitat Model for Regional Scale Evaluation of Management Decisions in the Virginian Province
EPA Grant Number: R830878Title: A Shallow-water Coastal Habitat Model for Regional Scale Evaluation of Management Decisions in the Virginian Province
Investigators: Gallegos, Charles L. , Weller, Donald E. , Jordan, Thomas E. , Neale, Patrick J. , Megonigal, J. P.
Institution: Smithsonian Environmental Research Center
EPA Project Officer: Packard, Benjamin H
Project Period: June 1, 2003 through September 30, 2007
Project Period Covered by this Report: June 1, 2003 through September 30, 2004
Project Amount: $746,433
RFA: Developing Regional-Scale Stressor-Response Models for Use in Environmental Decision-making (2002) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Aquatic Ecosystems , Climate Change
Objective:
Management decisions to protect estuaries are being made in the context of unprecedented environmental changes. For example, increased ultraviolet (UV) radiation, especially the damaging UV-B, has been documented and is expected to continue even at temperate latitudes. The carbon dioxide concentration of the atmosphere rose by 30 percent in the 20th century and is continuing to climb at a rate of about 1 percent per year. The effects of CO2 and other greenhouse gases on global climate change are highly uncertain, but alteration of rainfall and runoff patterns are considered likely. Interactions between altered flow regimes and changes in land use patterns will have consequences for the delivery of sediments and nutrients to estuaries. Projecting the effectiveness of management actions must proceed on the basis of predictions from mathematical models, because experimental manipulations cannot be made on the relevant scales. However, the effects of simultaneous, multiple stressors previously have not been incorporated into models of ecosystem processes.
Our modeling efforts focus on shallow tributary embayments and small tidal creeks of the Chesapeake Bay, because the ecological importance of shallow systems far exceeds their volumetric contribution to the Bay. Their importance derives from the many hectares of potential habitat for submersed aquatic vegetation created by their highly indented shorelines and from their role as spawning and nursery grounds for finfish and as refuge habitat for juvenile fish and crabs. The endpoints for our model will be indicators used as delisting criteria for the Chesapeake Bay, namely chlorophyll, water clarity (diffuse attenuation coefficient), and dissolved oxygen.
The objective of this research project is to represent shallow subestuaries as well-mixed compartments that receive and process inputs from their local watershed and exchange materials at their seaward boundaries. Mass balance modeling techniques will be employed for the model structure, with rate processes dependent upon interactions among stressors. For stressor interactions in the watershed, we will consider interactions between climate-induced flow alteration with changes in land use as they impact delivery of nutrients and sediments to the estuary. We also will consider the interactions between rising CO2 in wetlands and wetland distribution on delivery of dissolved organic matter. In the estuary, we will model interactions among nutrients, sediments, dissolved organic matter, and UV-B on plankton growth and light penetration. We will use a Monte Carlo approach that will facilitate investigation of alternative management scenarios and predict cumulative distribution functions of the delisting criteria for comparison with reference curves, which currently are under development.
Progress Summary:
Progress-to-date has consisted of the identification of component models from the literature for selected processes, identification of data sets for model testing, and preliminary analyses of morphometric features of a number of tributary embayments and their watersheds. We have completed a preliminary geographic information systems (GIS) analysis of the watersheds of 60 subestuaries arranged around the shore of Chesapeake Bay. Twenty-seven of the 62 are overlapping with subestuary-watershed systems that are the focus of our ongoing project with the Science To Achieve Results (STAR) Eagles program. The preliminary analysis documents the range of sizes and land use possibilities among the watersheds of the 60 subestuaries. Watershed areas range from 22-602 km2 with land cover percentages ranging from 1-75 percent forest, 0-85 percent cropland, 3-31 percent grassland, and 0.1-90 percent developed land. Further analyses will be undertaken to add additional subestuaries, incorporate updated land cover data, and develop a geographic description of the volume and shape of each subestuary.
We also have reviewed available watershed modeling tools, including models developed at the Smithsonian Environmental Research Center (SERC) and by scientists at other institutions. Under separate funding, we currently are leading a comparison of watershed models that have been applied in the Patuxent River watershed/subestuary system. The review and comparison will identify the best models for the objectives of our STAR project. A postdoctoral researcher will implement the watershed model analyses for the STAR project at the SERC in September 2004.
We have reviewed recent developments in modeling effects of UV radiation on phytoplankton photosynthesis. Models developed within the SERC photobiology group represent the state-of-the-art in that field. Existing models of UV response for Rhode River assemblages focus on photosynthesis and use a modification of the photosynthesis-irradiance equation to include a factor dependent on UV exposure:
where PB is the rate of photosynthesis normalized to chlorophyll-a content (gC g chl a-1 h-1), is a saturated rate of photosynthesis in the absence of photoinhibition, and Es is a saturation parameter for photosynthetically active radiation irradiance (EPAR, W m-2). E*inh is a dimensionless inhibition index derived from the UV irradiance spectrum using an appropriate weighting function. We evaluated the effectiveness of this model in predicting the growth of estuarine phytoplankton using existing data from culture chamber experiments with and without UV. The estimates were conservative; that is, growth was reduced at least as much as predicted. However, in some cases, greater than predicted inhibition occured apparently because of sensitivity to DNA damage from the artificial lamps in the chamber. This supports use of the model for estuarine work, because in-water exposure to DNA-damaging UV is very low. A report discussing the results has been submitted to Marine Ecology Progress Series.
A field program for determining the concentration of colored dissolved organic matter (CDOM) in runoff from different land uses and in marsh pore water as a function of CO2 concentration was instituted in the spring of 2004. To date, 350 samples have been collected from 85 streams flowing into 26 shallow tributary subestuaries.
Future Activities:
In the coming year we will focus on GIS analysis of small tributary embayments, coding and testing of model components, and analysis of CDOM flux data.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 23 publications | 4 publications in selected types | All 4 journal articles |
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Type | Citation | ||
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Litchman E, Neale PJ. UV effects on photosynthesis, growth and acclimation of an estuarine diatom and cryptomonad. Marine Ecology Progress Series 2005;300:53-62. |
R830878 (2003) R830878 (2004) R830878 (Final) |
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Supplemental Keywords:
Chesapeake Bay, modeling, water quality, dissolved oxygen, water clarity, chlorophyll, subestuaries, UV radiation, wetlands, suspended sediments, anthropogenic, anthropogenic stress, aquatic species vulnerability, atmospheric chemistry, biodiversity, climate, climate model, climate variability, climatic influence, coastal ecosystem, ecological models, ecosystem assessment, environmental measurement, environmental stress, global change, land use, meteorology, plankton, regional anthropogenic stresses., RFA, Scientific Discipline, Air, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, climate change, State, Air Pollution Effects, Monitoring/Modeling, Regional/Scaling, Environmental Monitoring, Ecological Risk Assessment, Atmosphere, anthropogenic stress, coastal ecosystem, aquatic species vulnerability, biodiversity, environmental measurement, ecosystem assessment, meteorology, climatic influence, Virginia (VA), global change, anthropogenic, climate models, UV radiation, greenhouse gases, environmental stress, coastal ecosystems, plankton, water quality, ecological models, climate model, Global Climate Change, land use, regional anthropogenic stresses, atmospheric chemistry, stressor response model, climate variabilityProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.