Final Report: CISNet: Molecular to Landscape-Scale Monitoring of Estuarine Eutrophication

EPA Grant Number: R826944
Title: CISNet: Molecular to Landscape-Scale Monitoring of Estuarine Eutrophication
Investigators: Morris, James T. , Fletcher, Madilyn , Jensen, John , Lewitus, Alan , Noble, Peter , Porter, Dwayne
Institution: University of South Carolina at Columbia
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 1998 through September 30, 2001 (Extended to September 30, 2002)
Project Amount: $579,650
RFA: Ecological Effects of Environmental Stressors Using Coastal Intensive Sites (1998) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Environmental Statistics , Ecosystems

Objective:

The objective of this research project was to assess the development of new and emerging technologies to aid the assessment of environmental quality and monitoring of coastal ecosystems. Three major hypotheses were addressed: (1) The composition and abundance of bacterial and phytoplankton communities will differ among estuaries as functions of nutrient availability. (2) Bacterial and phytoplankton communities form associations, which vary in complexity (species diversity) as a function of nutrient availability. (3) At a landscape-scale, remote sensing of the concentration of chlorophyll in emergent wetland vegetation will provide a quantitative index of wetland condition and will demonstrate differences in nutrient loading among estuaries. In the course of testing the first two hypotheses, we tested the efficacy of new techniques involving molecular tools and pigment analyses for assessing the composition of bacterial and phytoplankton communities, respectively, in estuaries. The third hypothesis focused on new methods for assessing the status of coastal wetlands. Field work was conducted in the North Inlet estuary, South Carolina (a nutrient impoverished estuary) and the Ashepoo, Combahee, and Edisto Rivers (ACE) Basin estuary, South Carolina (a naturally fertile estuary).

Summary/Accomplishments (Outputs/Outcomes):

Hypotheses 1 and 2 were tested by analyzing samples of bacteria and phytoplankton in water samples collected from the two estuaries. Samples for bacterial community composition were collected seasonally at several locations in each estuary in tandem with phytoplankton samples. Bacterial samples were analyzed using genetic profiling techniques (polymerase chain reaction/denaturing gradient gel electrophoresis), and phytoplankton community composition was assessed by analyzing the types of photopigments that were present in water samples.

For analyses of plankton pigments, we used a method that makes use of high-performance liquid chromatography (HPLC), based on a method used by Van Heukelem and Thomas (2001). This method has been found to provide good pigment separation and sensitivity. Data from our HPLC analyses are included in Van Heukelem and Thomas (2001), who have acknowledged our CISNet grant.

A matrix factorization software program, CHEMTAX, has been used to relate HPLC pigment data to phytoplankton composition in the open ocean. We have applied this program to estuarine communities by calibrating it against phytoplankton monocultures isolated from estuarine environments. HPLC chromatograms were analyzed from 12 taxonomically diverse species acclimated to growth at saturating or limiting light and harvested from exponential or stationary growth phase. One significant finding of this work is the discovery that the CHEMTAX algorithm used to compute algal community composition from pigment data must be calibrated for each region. We envision that the combined applications of CHEMTAX and neural computing to HPLC pigment profiles will lead to a major advance in current capabilities in determining phytoplankton community composition.

Water samples were taken seasonally from our two study sites along an estuarine salinity gradient and analyzed for pigments and water quality to determine the effects of nutrient loads on their spatial and temporal distribution. The sites (ACE Basin and North Inlet estuaries) differ in the size of their watersheds and their nutrient loads. Phytoplankton community composition was assessed using HPLC, multivariate statistics, and neural network (NN) analyses. The correlations between pigment profiles and physicochemical properties were highly significant and have been summarized by Noble, et al. (submitted).

NNs were trained to relate HPLC pigment concentrations to environmental variables (e.g., light attenuation coefficient, salinity, and dissolved organic carbon). The Shannon diversity index, principle components, and cluster analyses revealed that the ACE Basin phytoplankton, in an estuary receiving higher amounts of nitrogen and phosphate, had a lower pigment diversity in the spring and were compositionally different from North Inlet phytoplankton, particularly during the summer time bloom (July to October). Higher nutrient loads in the ACE estuary, because of its larger watershed area, yielded high concentrations of chlorophylls a, c1, and c2; alloxanthin; peridinin; and diadinoxanthin, whereas lower nutrient loads in the North Inlet estuary yielded high concentrations of chlorophyll b, prasinoxanthin, and violaxanthin.

The trained NNs predicted light attenuation (R2 = 0.92), salinity (R2 = 0.82), organic and total suspended solids (R2 = 0.82, R2 = 0.85, respectively), and temperature (R2 = 0.80) with high accuracies, indicating that these variables are highly correlated with plankton community composition. However, the NN predicted other environmental parameters poorly (dissolved organic carbon, R2 = 0.63; ammonia, R2 = 0.60). Sensitivity analysis revealed that: (1) the concentration of the pigment 19’ butanoyloxyfucoxanthin increased, and the concentration of chlorophyll c2 decreased with increasing light attenuation values; (2) concentrations of alloxanthin, total carotene, and peridinin increased with decreasing salinity; (3) concentrations of lutein and 19’ butanoyloxyfucoxanthin increased with organic and total suspend solid concentrations; and (4) concentrations of 19’ butanoyloxyfucoxanthin, prasinoxanthin, 19’ hexanoyloxyfucoxanthin, and total carotene decreased, whereas fucoxanthin, violaxanthin, diadinoxanthin, zeaxanthin, and lutein increased with increasing temperature.

There were several noteworthy differences in the HPLC pigment profiles between the ACE Basin and North Inlet estuaries. For example, zeaxanthin (a carotenoid found in cyanobacteria) and alloxanthin (a marker carotenoid for cryptophytes), which generally made up a similar proportion of the biomass in both estuaries in July, contributed a lower percentage of pigment biomass in ACE basin than in North Inlet in September, whereas the contribution of fucoxanthin, a carotenoid considered a marker for diatoms, was relatively greater in the ACE Basin in September. These patterns are consistent with the paradigm that diatoms, generally respond favorably to high nutrient (especially NO3) inputs, whereas marine cyanobacteria (Synechococcus spp.) are adapted to oligotrophic conditions.

In general, the results of the phytoplankton study suggest that high nutrient loads affect the composition of phytoplankton communities of southeastern tidally dominated estuaries and that sensitivity analysis of trained NNs revealed the association of specific pigments to environmental parameters. The temporal patterns of pigments indicated that some phytoplankton groups were always present at North Inlet, whereas ACE Basin phytoplankton groups were ephemeral. These differences may be a consequence of the unpredictability and dominance of river discharge in the ACE Basin in contrast to the high environmental predictability of tidally dominated North Inlet. In other words, the ACE Basin is externally regulated, whereas North Inlet is internally regulated. We conclude that it is possible to predict the occurrence of plankton communities, including harmful algal blooms, on the basis of physical and chemical environmental variables. Novel numerical, analytical tools, like NNs, will be useful in making these predictions.

Hypothesis 3 was tested by seasonally taking in situ measurements of radiometric and biophysical (chlorophyll, biomass) characteristics at approximately 50 locations within each of the Spartina alterniflora-dominated study areas in North Inlet estuary and the ACE Basin. The geographical (x,y) location of each sample was recorded using GPS. The biophysical data (chlorophyll and biomass) were correlated to leaf radiance data collected using a 350 nm to 1050 nm portable field spectrometer (GER) and with remotely sensed data, Airborne Data Acquisition and Registration (ADAR). The ADAR System acquires digital photographs in four configurable spectral bands between 400 nm to 1000 nm with high (submeter) spacial resolution.

Spectrophotometer scans of plant leaves from experimentally fertilized plots demonstrated that significant differences exist between treatments in reflected light. Significant differences in canopy chlorophyll density were found between the North Inlet and ACE Basin estuaries, and it was shown that the chlorophyll:biomass ratio varies seasonally. Existing regression models (e.g., Normalized Difference Vegetation Index) were used to fit chlorophyll density to brightness values from ADAR imagery. In addition, a neural net was trained to classify ADAR imagery and to predict canopy chlorophyll density. The neural net model was significantly better at predicting chlorophyll than traditional regression approaches. NN algorithms are proving to be excellent tools for classifying coastal landscapes. We have found excellent resolution of wetland areas, open water, and uplands using this approach. Our data support Hypothesis 3 and provide evidence that remote sensing of biophysical properties of coastal wetlands can be a powerful tool for assessing their status.


Journal Articles on this Report : 13 Displayed | Download in RIS Format

Other project views: All 63 publications 15 publications in selected types All 15 journal articles
Type Citation Project Document Sources
Journal Article DeLorenzo ME, Lewitus AJ, Scott GI, Ross PE. Use of metabolic inhibitors to characterize ecological interactions in an estuarine microbial food web. Microbial Ecology 2001;42(3):317-327. R826944 (2000)
R826944 (2001)
R826944 (Final)
  • Abstract from PubMed
  • Full-text: State University of New York-Full Text PDF
    Exit
  • Abstract: SpringerLink-Abstract
    Exit
  • Journal Article Jensen JR, Schill SR. Bidirectional distribution function (BRDF) characteristics of smooth cordgrass (Spartina alterniflora) obtained using a Sandmeier Field Goniometer. Geocarto International 2000;15(2):23-30. R826944 (2000)
    R826944 (Final)
  • Abstract: Taylor & Francis-Abstract
    Exit
  • Journal Article Jensen JR, Olsen G, Schill SR, Porter DE, Morris J. Remote sensing of biomass, leaf-area-index and chlorophyll a and b content in the ACE Basin and National Estuarine Research Reserve using sub-meter digital camera imagery. Geocarto International 2002;17(3):27-36. R826944 (2000)
    R826944 (Final)
    R828677C003 (2002)
    R828677C003 (2003)
  • Abstract: Taylor & Francis-Abstract
    Exit
  • Journal Article Lewitus AJ, Koepfler ET, Pigg RJ. Use of dissolved organic nitrogen by a salt marsh phytoplankton bloom community. Archiv fur Hydrobiologie Special Issues, Advances in Limnology 2000;55:441-456. R826944 (1999)
    R826944 (2000)
    R826944 (2001)
    R826944 (Final)
  • Abstract: GetInfo-Citation
    Exit
  • Journal Article Lewitus AJ, Wetz MS, Koepfler ET, Hayes KC, Dame RF. Effects of oyster reefs on microbial community structure and production. Journal of Shellfish Research 2001;20(1). R826944 (Final)
    not available
    Journal Article Lewitus AJ, Hayes KC, Willis BM, Burkholder JM, Glasgow HB, Holland AF, Maier PP, Rublee PA, Magnien R. Low abundance of the dinoflagellates, Pfiesteria piscicida, P. shumwayae, and Cryptoperidiniopsis spp., in South Carolina tidal creeks and open estuaries. Estuaries 2002;25(4):586-597. R826944 (2000)
    R826944 (2001)
    R826944 (Final)
    R827084 (Final)
  • Abstract: SpringerLink-Abstract
    Exit
  • Journal Article Morris JT, Sundareshwar PV, Nietch CT, Kjerfve B, Cahoon DR. Responses of coastal wetlands to rising sea level. Ecology 2002;83(10):2869-2877. R826944 (2000)
    R826944 (2001)
    R826944 (Final)
    R828677 (2001)
    R828677 (Final)
    R828677C003 (2003)
    R828677C003 (Final)
  • Full-text: ESA Ecology-Full Text HTML
    Exit
  • Abstract: ESA Ecology-Abstract
    Exit
  • Other: South Dakota School of Mines-Full Text PDF
    Exit
  • Journal Article Noble PA, Almeida JS, Lovell CR. Application of neural computing methods for interpreting phospholipid fatty acid profiles of natural microbial communities. Applied and Environmental Microbiology 2000;66(2):694-699. R826944 (1999)
    R826944 (2000)
    R826944 (2001)
    R826944 (Final)
    R824776 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: AEM-Full Text HTML
    Exit
  • Abstract: AEM-Abstract
    Exit
  • Other: AEM-PDF
    Exit
  • Journal Article Noble PA, Tymowski RG, Fletcher M, Morris JT, Lewitus AJ. Contrasting patterns of phytoplankton community pigment composition in two salt marsh estuaries in southeastern United States. Applied and Environmental Microbiology 2003;69(7):4129-4143. R826944 (2000)
    R826944 (Final)
    R828677C003 (2003)
    R829458 (2005)
    R829458C004 (2003)
    R829458C004 (2005)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: Applied and Environmental Microbiology-Full Text HTML
    Exit
  • Abstract: Applied and Environmental Microbiology-Abstract
    Exit
  • Other: Applied and Environmental Microbiology-Full Text PDF
    Exit
  • Journal Article Southerland HA, Lewitus AJ. Physiological responses of estuarine phytoplankton to ultraviolet light-induced fluoranthene toxicity. Journal of Experimental Marine Biology and Ecology 2004;298(2):303-322. R826944 (2000)
    R826944 (Final)
  • Full-text: Science Direct-Full Text HTML
    Exit
  • Other: Science Direct-PDF
    Exit
  • Journal Article Van Heukelem L, Thomas CS. Computer-assisted high-performance liquid chromatography method development with applications to the isolation and analysis of phytoplankton pigments. Journal of Chromatography A 2001;910(1):31-49. R826944 (2000)
    R826944 (2001)
    R826944 (Final)
  • Abstract from PubMed
  • Full-text: NASA-Full Text PDF
  • Abstract: Science Direct-Abstract
    Exit
  • Other: Science Direct-Full Text PDF
    Exit
  • Journal Article Wetz MS, Lewitus AJ, Koepfler ET, Hayes KC. Impact of the eastern oyster Crassostrea virginica on microbial community structure in a salt marsh estuary. Aquatic Microbial Ecology 2002;28(1):87-97. R826944 (2000)
    R826944 (2001)
    R826944 (Final)
  • Full-text: Aquatic Microbial Ecology-Full Text PDF
    Exit
  • Abstract: Aquatic Microbial Ecology-Abstract
    Exit
  • Journal Article White DL, Porter DE, Lewitus AJ. Spatial and temporal analyses of water quality and phytoplankton biomass in an urbanized versus a relatively pristine salt marsh estuary. Journal of Experimental Marine Biology and Ecology 2004;298(2):255-273. R826944 (2000)
    R826944 (Final)
  • Full-text: ScienceDirect-Full Text HTML
    Exit
  • Other: ScienceDirect-PDF
    Exit
  • Supplemental Keywords:

    estuarine eutrophication, remote sensing, productivity, nutrients, phytoplankton community, HPLC pigments, canopy chlorophyll, neural net,, RFA, Scientific Discipline, Water, Ecosystem Protection/Environmental Exposure & Risk, Nutrients, Ecology, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, Chemistry, Monitoring/Modeling, Ecological Effects - Environmental Exposure & Risk, Environmental Monitoring, Ecological Risk Assessment, Biology, Watersheds, anthropogenic stress, aquatic ecosystem, coastal ecosystem, eutrophication, hydrological stability, nutrient supply, nutrient transport, remote sensing, ecological exposure, monitoring, scaling, chlorophyl, CISNet, wetland vegetation, estuaries, bacteria monitoring, coastal zone, remote sensing data, landscape-scale monitoring, esturarine eutrophication, phytoplankton nutrient, CISNet Program, phytoplankton dynamics, landscape monitoring, analytical chemistry, molecular monitoring, aquatic ecosystems, nutrient cycling, water quality, ecosystem health, stress responses, estuarine food web

    Relevant Websites:

    http://www.biol.sc.edu/~morris Exit

    Progress and Final Reports:

    Original Abstract
  • 1999 Progress Report
  • 2000 Progress Report
  • 2001 Progress Report