2003 Progress Report: Trophic Indicators of Ecosystem Health in Chesapeake Bay

EPA Grant Number: R828677C002
Subproject: this is subproject number 002 , established and managed by the Center Director under grant R828677
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: EAGLES - Atlantic Coast Environmental Indicators Consortium
Center Director: Paerl, Hans
Title: Trophic Indicators of Ecosystem Health in Chesapeake Bay
Investigators: Houde, Edward D. , Adolf, Jason , Boicourt, William C. , Connelly, W. , Harding Jr., Lawrence W. , Jordan, Christy , Jung, Sukgeun , Kimmel, David G. , Magnuson, Andrea , Miller, W. David , Roman, Michael R.
Current Investigators: Houde, Edward D. , Adolf, Jason , Boicourt, William C. , Connelly, W. , Gallegos, Charles L. , Harding Jr., Lawrence W. , Jordan, Christy , Jung, Sukgeun , Kimmel, David G. , Magnuson, Andrea , Miller, W. David , Rakocinski, Chet , Roman, Michael R.
Institution: University of Maryland , University of Maryland Center for Environmental Science
Current Institution: University of Maryland Center for Environmental Science , University of Maryland , University of Mississippi Main Campus
EPA Project Officer: Hiscock, Michael
Project Period: March 1, 2001 through February 28, 2003
Project Period Covered by this Report: March 1, 2002 through February 28, 2003
RFA: Environmental Indicators in the Estuarine Environment Research Program (2000) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Water , Ecosystems


The objectives of this research project are to: (1) develop indicators capable of determining plankton and fish community structure and function (i.e., indices of trophic transfer); (2) couple these indicators to physical-chemical and remote sensing assessments of ecosystem condition; and (3) explicitly evaluate the roles of climate, environmental factors, dissolved oxygen, and nutrient loading on community structure and trophic state.

Progress Summary:

Remote Sensing and Bio-Optics

We have continued SeaWiFS Aircraft Simulator (SAS III) flights on the main stem of Chesapeake to measure chlorophyll and temperature distributions. The Chesapeake Bay Remote Sensing Program consists of more than 20 flights per year, and a companion program has conducted 8-12 flights per year on 2 tributaries of focus, the Choptank and Patuxent Rivers River. The National Aeronautics and Space Administration (NASA) component of Atlantic Coast Environmental Indicators Consortium (ACE INC) currently supports flights, maintaining a 15-year time series that has generated data of high spatial and temporal resolution for key ecosystem properties such as chlorophyll (Chl-a) and primary productivity (PP). Examples of a spring to early summer series of Chl-a distributions from aircraft remote sensing reveal the development of phytoplankton biomass in a year of moderate flow (see Figure 1).

Distributions in Chesapeake Bay From Aircraft Remote Sensing of Ocean Color Using SAS III for Six Dates in Spring-Summer 2000

Figure 1. Chlorophyll (Chl-a, mg m-3) Distributions in Chesapeake Bay From Aircraft Remote Sensing of Ocean Color Using SAS III for Six Dates in Spring-Summer 2000.

Research cruises in support of ACE INC to characterize phytoplankton dynamics and bio-optical parameters of the water column were conducted on seven occasions in 2003. Three cruises (April, July, and October) were conducted on the Choptank and Patuxent Rivers in association with ACE INC. Four cruises (April, August, October, November) were conducted on the main stem Chesapeake Bay in conjunction with related projects, including National Science Foundation (NSF) Biocomplexity in collaboration with Bess Ward, NSF Microbial Observatory for Virioplankton Observatory with Eric Wommack and Wayne Coats, and NSF Small Grants Emergency Response that supported a post-Hurricane Isabel cruise by our ACE INC group. The first set provided coverage of the main stem bay and adjacent coastal waters; the second set gave coverage of the Choptank and Patuxent Rivers concurrent with surveys of physical properties, zooplankton sampling, and fish trawls; a third set sampled the Bay before and after passage of Hurricane Isabel in fall 2003 to measure changes in plankton and fish communities associated with this strong storm. Bio-optical measurements on all cruises supported the remote sensing efforts and included: (1) Chl-a; (2) particulate absorption; (3) CDOM absorption and fluorescence; (4) seston; (5) HPLC pigment determinations; (6) in-water profiles of downwelling irradiance and upwelling radiance from a suite of instruments to recover remote sensing reflectance; and (7) sun photometer measurements for atmospheric turbidity. The optical instruments for profiles included a Satlantic hyperspectral tethered radiometer buoy and two profilers, a Biospherical Instruments MER-2040 and a Satlantic MicroPro. Deployment of these instruments is supporting QA/QC of radiometry for ACE INC and comparisons with satellite and aircraft recoveries of key ecosystem properties.

The Chesapeake Bay group has applied recently published models of PP (Harding et al., 2002) to the complete time-series of remote sensing data to generate spatially explicit outputs of PP for the main Bay. These data are now being analyzed to develop predictive capabilities for this integrative indicator of ecosystem function for the Bay. The specific approach combines data on freshwater input and nutrient loading to the estuary with the greater than 400 time point data set developed from the remotely sensed data and models applied. We reported on progress at an international symposium on primary productivity in the oceans in Bangor, Wales in March 2002. Measurements of PP on the main stem Bay and tributary cruises were conducted throughout 2002 to obtain validation data for model outputs and the data are now being processed and analyzed. Progress on this aspect of our work supported presentations at the EaGLes meeting in Bodega Bay in December, and at ASLO/TOS 2004 Ocean Research Conference in Honolulu in February, and the results are now being prepared for publication.

We have used Chl-a biomass (mg m-3), floral composition (as fraction of Chl-a - f_ Chl-a - attributable to specific taxonomic groups), and community size structure as phytoplankton indicators, each of which conveys an independent aspect of phytoplankton dynamics (see Figure 2). Major objectives of our work are to: (1) quantify the responsiveness of these indicators to environmental variability, focusing on freshwater flow and nutrient loading from the watershed; (2) quantify the relationships among these indicators, how floral composition, biomass, cell size distribution, and PP co-vary and are forced by similar environmental drivers; and (3) detail the ramifications for ecosystem function. Chl-a biomass is generally regarded as a good indicator of trophic status, as Chl-a tends to increase as a function of nutrient loading. Floral composition and cell size distribution serve as ‘qualitative’ descriptors of the phytoplankton biomass captured in Chl-a measurements, which may impact the fate of phytoplankton biomass captured in our Chl-a measurements. Further, floral composition and size structure of the phytoplankton can potentially respond to environmental forces that do not affect Chl-a biomass. Consideration of combinations of Chl-a biomass, floral composition, and size structure can be used to the estimate the fates of phytoplankton, such as sedimentation (high biomass, large diatoms) or HAB formation (high biomass, high % dinoflagellates).

The main stem of Chesapeake Bay is a diatom-dominated system wherein seasonal variability of temperature and Susquehanna River flow (SRF) explains most of the annual variability of floral composition (see Figure 2). Seasons are characterized by particular combinations of floral composition, Chl-a biomass, and PP. In our analysis of a 6-year dataset, each season was characterized by regional blooms of recurring taxa related to trophic gradients in the main stem of the Bay. Interannual variability of phytoplankton dynamics in spring and summer was primarily driven by freshwater input that stimulated diatoms. Thus, diatoms were highly responsive to large-scale nutrient inputs such as those that attended freshwater inputs. These responses were most pronounced in the lower Bay in the summer where high SRF precipitated a floral shift from picoplanktonic (< 3 μm) cyanobacteria to larger diatoms.

Conditions of Phytoplankton Floral Composition, Chl-a Biomass, and Primary Productivity in the Main Stem of Chesapeake Bay. These conditions represent long term averages derived from the LMER TIES dataset (1995-2000)

Figure 2. Conceptual Diagram Showing ‘Typical’ Conditions of Phytoplankton Floral Composition, Chl-a Biomass, and Primary Productivity in the Main Stem of Chesapeake Bay. These conditions represent long term averages derived from the LMER TIES dataset (1995-2000).

ACE INC sampling in 2002 and 2003 compared phytoplankton indicators in the Choptank and Patuxent Rivers. In 2003, flow cytometric measurements of phytoplankton community size distribution were added to core measurements of biomass and floral composition. Figure 3 illustrates seasonal relationships among floral composition, Chl-a biomass, and cell size distribution. Relative size distribution was measured with a Becton Dickinson FACSCalibur flow cytometer (see Figure 3A, B), using an empirical algorithm developed in an REU Fellowship project (Miranda Hoover, Wittenburg University) to relate side-scatter to cell size. Here, the size distribution is scaled between 0 and 1 for presentation. High flow in spring 2003 pushed biomass distributions toward the mouths of each river where phytoplankton were characterized by relatively large diatoms. The average cell size of phytoplankton was smaller in the summer than in the spring. The advantage of combining these different phytoplankton indicators is that community size distribution associated with diatom assemblages in spring (large cells) and summer (small cells) carries different ecological ramifications for the fate of algal biomass. Future studies will attempt to quantify relationships between phytoplankton and higher trophic levels, drawing on biomass, floral composition and size distribution data measured in this study.

We examined the role of synoptic scale weather patterns as a driver of indicator variability across all trophic levels. Most of the indicators that have been identified for the Chesapeake Bay exhibit strong seasonal to interannual variability associated with environmental forcing. On those seasonal to interannual time scales, much of the environmental variability is related to differences in regional-scale weather patterns. By quantifying the variability of atmospheric circulation and its associated influence on environmental variables, we hope to quantify the variability of identified indicators associated with climate variability, and by difference relate the remaining variability to changes in the ecosystem structure and function.

Spring and summer Chl-a Biomass

Figure 3. Spring and summer Chl-a Biomass (bars, mg m-3), Floral Composition (colored lines, fraction of Chl-a - f_Chl-a), and Relative Size Distribution (heavy black line). Taxa are represented by colors: diatoms (brown), chlorophytes (green), dinoflagellates (red), cryptophytes (orange), cyanobacteria (blue), haptophytes (yellow). Panels A and B show representative cytograms from assemblages dominated by: (A) small and (B) large cells.

Recent work has focused on developing a water balance model for the Susquehanna River basin, the primary freshwater source for Chesapeake Bay. Variability of freshwater flow from the Susquehanna influences phytoplankton biomass, particularly in the spring when nutrients and sediments associated with flow determine the light and nutrient conditions of the Bay of (see Figure 4). By developing a water balance model that is forced by synoptic-scale weather patterns, we have been able to identify and quantify the type of weather that most strongly influences phytoplankton dynamics.

Synoptic climatology is a statistical approach to classifying and quantifying variability in atmospheric circulation at a regional spatial scale. Each day’s weather is clustered into one of ten dominant patterns. These weather patterns have distinct meteorological conditions associated with them, including probability and amount of precipitation, temperature, and wind speed and direction. These parameters then are used in a water balance model to estimate freshwater flow from the river basin. This approach allows us to predict monthly to seasonal freshwater flow based on earlier months’ atmospheric circulation and thereby predict phytoplankton biomass on seasonal and regional time and space scales.

Conceptual Links of Atmospheric Circulation, Precipitation, River Flow, and Phytoplankton Dynamics

Figure 4. Conceptual Links of Atmospheric Circulation, Precipitation, River Flow, and Phytoplankton Dynamics

Oxygen and Residence Time Component Indicators

Dissolved oxygen and residence time have been proposed as component variables for incorporation into useful indicators of estuarine health. Both field and analytical efforts are being employed to develop meaningful formulations of these variables.

In the analytical arena, two approaches are being employed. First, a below-pycnocline residence time is being calculated for compartments of stratified estuaries to examine whether such a formulation will represent an index for nutrient loading and oxygen dynamics. This formulation will be used to compare the Chesapeake Bay and the Neuse River, as well as stratified tributary estuaries such as the Choptank, Patuxent, and Pocomoke Rivers. Such a formulation may well work with macro-tidal estuaries with lower stratification, such as the Parker River/Plum Island Sound and North Inlet estuaries, but modifications may be necessary.

A simple advection-diffusion model has been constructed that is expected to provide a convenient assessment of residence time for estuarine sub-regions. This model has been coded, debugged, and successfully run for the Choptank River. A strong advantage of this modeling approach is that it can provide an accounting of salt storage (and residence time) within the tributary estuary and significantly improved estimates of exchange between the tributary and the main stem estuary. The longitudinal structure of exchange coefficients in the Choptank River showed a marked maximum in mid-estuary, where peak values were a factor of 5 greater than in surrounding regions. Further analysis revealed a confined region of elevated gravitational circulation located between the 1-layer circulation in the upper reaches and the pulsed, wind-driven circulation in the lower reaches. A similar structure has been discovered in the Pocomoke River estuary.

Efforts are underway to tune the coefficients, test the accuracy of the model on the ACE INC surveys, and then apply the model to the Patuxent River and Pocomoke River estuaries. Although residence time formulations are being developed for this model, the utility of a two-dimensional model also is being explored. Such an approach is expected to directly capture the gravitational circulation in key reaches of these tributaries. A two-dimensional model is not expected to provide a convenient indicator, as a result of the effect of spin-up effort, but it will likely provide helpful tests of candidate formulations.

For the field effort, we are focusing on the exchange dynamics and short-term oxygen variability of the Patuxent River and Choptank River estuaries, using shipboard axial surveys and moored sensors. These field measurements, while undertaking a comparative approach, also extend the time-series program in the Choptank that was initiated in the CISNet study. In addition to employing standard CTD surveys, a rapid sampling towed vehicle, the ACROBAT, has been used to delineate the fine structure in the physical field, and the fine structure of oxygen, chlorophyll, and zooplankton distributions. In 2002, the ACROBAT resisted attempts to achieve stable flight performance with its heavy instrument payload. Acquisition of larger control surfaces, and refinement of the trim settings proved successful in 2003, enabling reliable performance in the tributary surveys.

Part of the field effort has been evaluation of in situ oxygen sensors in the hostile conditions of high bio-fouling and anoxia common to coastal waters during the summer season. The Stephens-Greenspan oxygen sensor was deployed in a variety of environments in the Choptank River and main stem Chesapeake Bay to test its ability to handle the deleterious effects of bio-fouling and hypoxia. This sensor maintained accuracy considerably longer (> 1 month) than other probes under bio-fouling and hypoxic conditions. We also acquired the new Aanderaa/PerSens Optode oxygen sensor for similar evaluation. Fortuitously, this instrument was deployed at 10 m in Chesapeake Bay in late summer 2003, prior to Hurricane Isabel. The resulting record (see Figure 5) showed nicely the transition between hypoxic and aerated conditions following the storm on September 18-19. Perhaps even more important for oxygen dynamics, the instrument properly tracked a wind-stirring event and return to hypoxia on September 13-14 after a long interval of anoxia.

Axial Velocity (Positive Seaward), Salinity, and Dissolved Oxygen at Chesapeake Bay Observing System Mid-Bay Mooring in August-September 2003

Figure 5. Axial Velocity (Positive Seaward), Salinity, and Dissolved Oxygen at Chesapeake Bay Observing System Mid-Bay Mooring in August-September 2003. Currents are shown at 2.4 and 10 m depth, salinity at 2.4 and 19 m depth, and the Aanderaa/PerSens Optode was deployed at 10 m depth.

Zooplankton as Indicators of Climate Change and Trophic Change in Estuaries

Spatial and temporal changes in zooplankton community composition and abundance have been observed in response to freshwater input in the Chesapeake Bay. To determine how freshwater flow directly impacts zooplankton species in the Chesapeake Bay, statistical models were constructed from long-term monitoring data. The purpose of the models was to identify how changing estuarine conditions that accompanied increases or decreases in freshwater input impacted zooplankton dynamics. Significant deviations from the models were found for particular time periods and correlated with water quality conditions. Time periods showing the strongest deviations from the model were typically “wet” or “dry” years (Figure 6). Therefore, we believe that zooplankton may be used as indicators of changes in estuarine condition that relate to freshwater discharge (Kimmel and Roman, 2004).

Conceptual Diagram of Upper Chesapeake Bay Response to Dry (left) and Wet (right) Conditions

Figure 6. Conceptual Diagram of Upper Chesapeake Bay Response to Dry (left) and Wet (right) Conditions. The use of synoptic climatology patterns will be used to predict wet and dry periods and the ecosystem response.

Chesapeake Bay zooplankton covaried with regional weather patterns calculated from data on sea level pressure. Particular weather patterns impacted the Chesapeake Bay region differently, causing variations in temperature, precipitation, cloud cover, and so on. Weather pattern anomalies were calculated and correlated with shifts in mesozooplankton abundance and community composition. Winter-spring weather conditions appeared to influence the distribution of zooplankton in the spring and summer. We are currently using synoptic climatology to predict the water balance for the Susquehanna River Basin. This will allow prediction of the magnitude of the spring freshwater input and can be used to drive models of zooplankton dynamics that rely on freshwater input as a major driver. Thus, the prediction of zooplankton response to weather patterns is possible.

Zooplankton may be used as indicators of trophic condition. We have recently focused on the use of biomass size spectra as an indicator of zooplankton response to changes in the Chesapeake Bay ecosystem (see Figure 7). The distribution of zooplankton biomass in the Chesapeake Bay appears to vary significantly throughout the year. The slope of the size spectra appears to vary with hydrologic conditions, including nutrient inputs, thus may serve as a tool to assess the efficacy of nutrient reduction efforts. The zooplankton size spectra will be combined with phytoplankton and fish size spectra to create a whole ecosystem based indicator.

Biomass Size Spectra Slope Values for Each 3 Regions of Chesapeake Bay

Figure 7. Biomass Size Spectra Slope Values for Each 3 Regions of Chesapeake Bay. Size spectra slope may be used as an indicator of nutrient reduction efforts and their impacts on zooplankton.

Fish Community Structure and Trophic State

Biomass size spectra of fishes collected in the TIES Program (1995-2000) have been modeled and analyzed. Parameters of these models can serve as indicators of trophic state. The spectra are multi-modal, with two major modes that represent: (1) small forage fishes (e.g., bay anchovy) that feed primarily on zooplankton and (2) larger carnivorous fishes (e.g., Atlantic croaker and white perch) that forage on benthic invertebrates and smaller fishes. The structure and variability in biomass modes and the slopes of normalized spectra (abundance-at-size relative to size) are the parameters that are indicators of fish community structure.

Spectra for 6 years, 1995-2000, have been modeled. Normalized spectra (biomass density/size = abundance density) for components of the fish community that include only zooplanktivorous and piscivorous fishes (direct trophic link; see Figure 8) have a slope coefficient near a theoretical -1.0, a value expected if the un-normalized biomass spectrum were ‘flat’. Spectral slopes and intercepts differ among years, mostly from variability in the first dome of the spectrum, which primarily indicates variable bay anchovy recruitment and biomass levels that respond dynamically to environmental conditions (e.g., freshwater flow, dissolved oxygen). Parameters describing the second dome (larger fishes) are relatively constant in the spectral analysis, but the dominant species that contribute to biomass in this dome varied among years.

Normalized Biomass Size Spectra for Zooplanktivorous Fish

Figure 8. Normalized Biomass Size Spectra for Zooplanktivorous Fish (Primarily Bay Anchovy) and Piscivorous Fish in the Chesapeake Bay, Averaged for Years 1995-2000. The slope is approximately equal to a theoretical value of 1.0. a = -1.05, the slope of the regression function; H0 = 9.64, the intercept; H1 = 2.80, the amplitude of the cyclic function; R = the prey:predator size ratio.

Preliminary analysis of biomass size spectra for fishes in the Choptank (agricultural drainage) and Patuxent Rivers (urbanized drainage), based on trawl collections in 2002 and 2003, does not indicate strong differences between rivers in spectral properties of the respective fish communities. Slopes of normalized spectra in both rivers are less steep than a theoretical -1.0. Spectra in both rivers are dominated by abundance and biomasses of anadromous fishes (white perch, striped bass, river herrings) in spring and summer and by recruiting bay anchovy from late summer to fall. There are clear shifts in dominant species along the salinity gradients in both rivers. Anadromous fishes, although common in both rivers, are more dominant in the oligohaline portion of the Choptank than in the Patuxent.

Integration and Synthesis

Integrated analysis and synthesis of data from Chesapeake Bay research and monitoring programs are being conducted across trophic levels to develop indicators of trophic state and to relate these indicators to variability of hydrographic properties, estuarine circulation, and environmental factors. Indicators that are specific to each trophic level were described earlier in the report.

Biomass size spectra models that include three trophic levels and integrate information on community structure for phytoplankton, zooplankton, and fish are being developed. Zooplankton and fish presently are included in these models (see Figure 9). Model parameter estimates can serve as indicators. For zooplankton and fish, the slope coefficient (-1.41), is significantly steeper than -1.0, suggesting that the Chesapeake Bay ecosystem is stressed. In addition to integrative, retrospective analyses, we conducted surveys in the Patuxent and Choptank River sub-estuaries to obtain new information on hydrographic properties, environmental variability, plankton, and fish. These coordinated, interdisciplinary efforts provide data to compare and characterize biological productivity, community structure, and trophic state, from which we are developing indicators of ecosystem status. A schematic diagram illustrates this approach (Figure 10).

Normalized Biomass Size Spectrum for Zooplankton, Zooplanktivorous Fish, and Piscivorous Fish in the Chesapeake Bay (1997 and 1999 combined data)

Figure 9. Normalized Biomass Size Spectrum for Zooplankton, Zooplanktivorous Fish, and Piscivorous Fish in the Chesapeake Bay (1997 and 1999 combined data). W = body mass (g); a = slope; H0 = intercept; H1 = amplitude of the cyclic function; R = prey:predator size ratio.

Three surveys (April, June, July), each of 4 days’ duration, were conducted during 2002 and 2003 in each river. We hypothesized that quality of habitat and productivity differ between the two rivers, with healthier biological communities predicted in the Patuxent in response to recent reductions in nutrient loading and improved water quality in that urbanized watershed compared to the Choptank where non-point-source nutrient loading from agricultural drainage has increased. Phytoplankton is sampled to characterize distribution and abundance of Chl-a as an index of biomass. PP is measured in simulated in situ sunlight incubations using 14C tracer techniques. Pigment composition is assessed by HPLC, and bio-optical measurements (inherent optical properties) are measured with in-water radiometers. Ancillary measurements are made of dissolved inorganic nutrients and suspended particulate matter. Zooplankton sampling includes optical plankton counter and acoustic measurements, and traditional tow-and-pump sampling techniques to analyze the size range and biomass of zooplankton in both systems to develop biomass size spectra and to characterize species composition and abundance. Fish collections are made with a midwater trawl, and ichthyoplankton and jellyfishes are sampled with a Tucker trawl. Data on taxa, abundances, sizes, feeding habits, and age/size structure are being analyzed.

Schematic of Biomass Size Spectrum and Related Hypotheses in the Chesapeake Bay

Figure 10. Schematic of Biomass Size Spectrum and Related Hypotheses in the Chesapeake Bay. The slope linking zooplanktivorous fish to piscivorous fish (a) represents a direct trophic link. The slope linking zooplanktivorous fish to total fish biomass in the second dome (b) represents an indirect link because the benthivorous fish also feed on benthic invertebrates whose biomass is not represented in our data. The schematic also shows Atlantic menhaden and jellyfishes that are not included in our data at present, which could, in part, explain the gap between the two fish biomass domes.

Future Activities:

Remote Sensing and Bio-Optics

We will continue with the Year 3 objectives and research schedule, with increased emphasis on applying indicators to other estuarine systems, including the Neuse-Pamlico Sound systems. We will compare and cross-calibrate pigment-based indicators of phytoplankton functional groups as well as zooplankton and higher trophic-level indicators between Chesapeake and these systems.

Oxygen and Residence Time Component Indicators

Upon completion of candidate residence-time formulations, these component indicators will be tested by comparisons between the Chesapeake Bay and the Neuse River, and among three Chesapeake Bay tributaries. Following these tests, indicators will be applied to the macrotidal systems of Parker River and North Inlet. The initial residence-time and oxygen-based indicators are deliberately intended to be simple, enabling convenient assessment while trying to capture the essence of first-order ecosystem dynamics. A strong effort will be exerted, with the aid of simple models, to increase the power of broader indices by incorporating the key physical processes of stratification and mixing (including wind) into the trophic state analysis and modeling.

Zooplankton as Indicators of Climate Change and Trophic Change in Estuaries

The objectives will remain the same as the Year 3 objectives. We will continue to analyze short- and long-term zooplankton data sets to identify and potentially distinguish climatic from other drivers of community structure and function. In addition, efforts will be made to establish a comparative zooplankton community data set for the Neuse-Pamlico system in collaboration with Dr. H. Paerl and colleagues at University of North Carolina at Chapel Hill (UNC-CH) Institute of Marine Sciences. A UNC-CH graduate student (Amy Waggener) has been trained to initiate routine zooplankton data collection and analysis for the Neuse R. Estuary. This will form part of her M.S. thesis.

Fish Community Structure and Trophic State

A detailed analysis of statistical properties of biomass size spectra will be undertaken to further develop indicators of trophic state, based on fish community structure. Our preliminary analysis suggests that relative dominance of trophic guilds (zooplanktivores, benthivores, piscivores) varies annually in response to suites of environmental factors (e.g., salinity, dissolved oxygen, freshwater flow) and that slope coefficients of biomass size spectra are strongly correlated with principal components derived from multivariate statistical analyses. Further analysis will be directed at converting these complex statistical relationships into simple indicators, and perhaps predictors, of trophic state of Chesapeake Bay fish communities. We have proposed to present results of our fish-community indicators research at the U.S. Environmental Protection Agency (EPA) Environmental Monitoring and Assessment Program Monitoring Symposium in May 2004.

Field efforts to develop fish-community indicators will continue in 2004. Fish surveys will focus on developing statistical models to explain short-term variability in fish community structure, biomass size spectra, and relationships to environmental factors in the Choptank and Patuxent Rivers. We have submitted an abstract and proposal to present results of the Choptank-Patuxent research at the American Society of Limnology and Oceanography summer meeting in June 2004, especially relationships of fish biomass size spectra to estuarine salinity gradients.

Integration and Synthesis

Integrated modeling and analyses will be emphasized in 2004. Surveys on the Choptank River will be conducted at 2-week intervals in the spring and summer months to determine short-term variability and ontogeny in community structure and trophic relationships of primary producers, zooplankton and fish. Biomass size spectra that include the three trophic levels will be modeled to develop indicators of trophic status and change in relation to environmental factors.

We will make a dedicated effort in 2004 to deliver products and results of our ACE INC research to stakeholders in the Chesapeake Bay Program (CBP). Presentations of our indicators research will be made to the Scientific and Technical Advisory Committee and the Living Resources Subcommittee of the CBP, and to EPA managers who are charged with evaluating status of the Bay and protecting its resources. Our trophic state, climatology, and dissolved oxygen indicators will provide new tools to evaluate status of resources and need for restoration efforts.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 83 publications 18 publications in selected types All 18 journal articles
Other center views: All 383 publications 99 publications in selected types All 88 journal articles
Type Citation Sub Project Document Sources
Journal Article Magnuson A, Harding Jr. LW, Mallonee ME, Adolf JE. Bio-optical model for Chesapeake Bay and the Middle Atlantic Bight. Estuarine, Coastal and Shelf Science 2004;61(3):403-424. R828677 (Final)
R828677C002 (2003)
R828677C002 (Final)
  • Full-text: ScienceDirect-Full Text HTML
  • Other: ScienceDirect-PDF
  • Journal Article Miller WD, Kimmel DG. Synoptic climatology predictions of freshwater flow to Chesapeake Bay. Water Resources Research (in preparation, 2004). R828677C002 (2003)
    not available
    Journal Article Miller WD, Harding LW Jr. Synoptic-scale climatic forcing of spring phytoplankton biomass in Chesapeake Bay. Estuarine, Coastal and Shelf Science (in preparation, 2004). R828677C002 (2003)
    not available

    Supplemental Keywords:

    phytoplankton, zooplankton, fish, trophodynamics, size spectrum, bio-optics, remote sensing, primary production, HPLC, photopigments, dissolved oxygen, circulation, estuarine management, nutrients, regional scale indicators,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, RESEARCH, particulate matter, Air Quality, exploratory research environmental biology, Ecosystem/Assessment/Indicators, Ecosystem Protection, Air Pollutants, Chemistry, climate change, Air Pollution Effects, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Monitoring, Atmospheric Sciences, Environmental Engineering, Atmosphere, Ecological Indicators, ambient aerosol, environmental monitoring, remote sensing, aquatic ecosystem, anthropogenic stress, atmospheric dispersion models, ecoindicator, aerosol formation, fish habitats, atmospheric particulate matter, climate change effects, assessment models, environmental measurement, meteorology, climatic influence, air quality models, ozone, climate, global change, Choptank River, trophic effects, atmospheric transport, estuarine ecosystems, greenhouse gases, climate models, estuarine ecoindicator, atmospheric aerosol particles, airborne aerosols, environmental stress, water quality, climate model, ecological models, greenhouse gas, aerosols, atmospheric chemistry, climate variability, Global Climate Change, zooplankton, ambient air pollution

    Relevant Websites:

    http://www.aceinc.org Exit

    http://www.aceinc-umces.org/ Exit

    http://www.cbrsp.org Exit

    http://www.cisnet-choptank.org Exit

    Progress and Final Reports:

    Original Abstract
  • 2001
  • Final Report

  • Main Center Abstract and Reports:

    R828677    EAGLES - Atlantic Coast Environmental Indicators Consortium

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R828677C001 Phytoplankton Community Structure as an Indicator of Coastal Ecosystem Health
    R828677C002 Trophic Indicators of Ecosystem Health in Chesapeake Bay
    R828677C003 Coastal Wetland Indicators
    R828677C004 Environmental Indicators in the Estuarine Environment: Seagrass Photosynthetic Efficiency as an Indicator of Coastal Ecosystem Health