Grantee Research Project Results
2004 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, 2004 through September 30, 2005
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 alterations 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 relevant scales. The effects of simultaneous, multiple stressors have not, however, previously 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, from their role as spawning and nursery grounds for finfish, and as a refuge habitat for juvenile fish and crabs. The end points for our model will be those indicators being used as de-listing criteria for the Chesapeake Bay, namely chlorophyll, water clarity (diffuse attenuation coefficient), and dissolved oxygen.
Progress Summary:
Progress has been made on development of a 3-compartment subestuary model. The model domain includes three segments, with different volumetric dimension, lying between boundaries at the mouth and at the head of the subestuary. The watershed is considered to be an upstream boundary where multiple stressors such as inorganic nutrients, sediments, and dissolved organic matter are discharged. The downstream boundary is considered to be the Chesapeake Bay, or in some cases, a major tributary such as the Potomac or James River. Each subestuary segment has multiple ecological components (26 state variables), including dissolved inorganic nitrogen and phosphorus in water column, dissolved inorganic nitrogen and phosphorus in a phytoplankton cell (cell quota), size-fractionated phytoplankton (3 size classes) and zooplankton (3 size classes), dissolved organic nitrogen and phosphorus, bacteria, and detritus. Nitrogen and phosphorus are tracked separately to allow for spatial or temporal changes in the limiting nutrient (double-currency system), and light propagation through water column is computed based on empirical bio-optical algorithms. The bio-optical model creates depth- and wavelength-resolved underwater light fields which are used in primary production calculation. Surface light forcing that initiates the light propagation is calculated by a radiative transfer model (System for Transfer of Atmospheric Radiation) at given meteorological conditions and the astronomical position of the sun. The model assumes that each segment is vertically well mixed and horizontally exchanged with neighboring boxes. It does not, however, incorporate realistic features of the 3-dimensional advection and diffusion process. The coding of the physical exchange (with biological sources and sinks eliminated) and biological state equations (with physical exchange eliminated) were tested to ensure that the model conserves mass.
One project objective is to analyze how the geographic variability in physical structure and human use among the linked watershed-subestuary systems of the Chesapeake Bay affects estuarine response. The descriptive portion of this task has been completed. We have identified 128 Chesapeake Bay systems that fit our local watershed-subestuary paradigm and have captured the boundaries of these systems in a geographic information systems (GIS) database. Subestuary areas range from 0.1 to 101 km2 and their associated local watershed areas range from 6 to 1664 km2, with NLCD land cover percentages ranging from 6 to 81 percent forest, 1 to 64 percent cropland, 2 to 38 percent grassland, and 0.3 to 89 percent developed land. We also analyzed digital shoreline and bathymetric data to calculate a number of subestuary metrics, including subestuary area and water volume, mouth width and area of vertical profile, proportion of shallow water ( less than or equal to 2 meters) area, elongation ratio, fractal dimension, the ratio of subestuary perimeter to subestuary area, and the ratio of local watershed area to subestuary volume.
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, more than 1,600 samples have been collected from 97 streams flowing into 31 shallow tributary subestuaries.
Future Activities:
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) |
Exit Exit |
Supplemental Keywords:
Chesapeake Bay, modeling, water quality, dissolved oxygen, water clarity, chlorophyll, sub-estuaries, UV radiation, wetlands, suspended sediments,, 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.