Grantee Research Project Results
2002 Progress Report: Environmental Indicators in the Estuarine Environment: Seagrass Photosynthetic Efficiency as an Indicator of Coastal Ecosystem Health
EPA Grant Number: R828677C004Subproject: this is subproject number 004 , 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: Center for Integrating Statistical and Environmental Science
Center Director: Stein, Michael
Title: Environmental Indicators in the Estuarine Environment: Seagrass Photosynthetic Efficiency as an Indicator of Coastal Ecosystem Health
Investigators: Fonseca, Mark , Gallegos, Charles L. , Field, Donald , Thursby, G. , Kenworthy, Judson , Biber, Patrick
Institution: National Oceanic and Atmospheric Administration , University of North Carolina at Chapel Hill
EPA Project Officer: Packard, Benjamin H
Project Period: March 1, 2001 through February 28, 2003
Project Period Covered by this Report: March 1, 2001 through February 28, 2002
RFA: Environmental Indicators in the Estuarine Environment Research Program (2000) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Water , Aquatic Ecosystems
Objective:
The objectives of this research project are to: (1) create an indicator of estuarine health based on seagrasses; (2) examine the physiological state of seagrass in response to environmental conditions and correlate the plant's physiological state with ambient conditions based on both in situ and remote sensed data sources; and (3) evaluate the feasibility of scaling field assessments to remote sensed data sources.
Progress Summary:
Light availability to benthic seagrasses has been determined to be the major criterion limiting the distribution of seagrass in otherwise appropriate conditions. As light availability is based on water-column clarity, which is influenced by a multitude of anthropogenic and natural factors, issues related to monitoring light availability are paramount to managing seagrass habitats. We have initiated a monthly water-sampling program in North River, NC, and an estuary that contains considerable seagrass beds with a strong gradient in water clarity. Water samples are analyzed for absorption and scattering properties, and these are related to components of attenuation: chlorophyll, turbidity, and color. Data are being analyzed in collaboration with C. Gallegos at the Smithsonian Institute. Early results indicate that, per unit mass, suspended sediments in the Back Sound/Middle Marsh area absorb and scatter much less light than sediments in the mesohaline Chesapeake Bay.
Research has been initiated to link potential indicators of plant responses to water quality and light availability in an estuarine setting. Criteria for selection of successful indicators include:
Based on these criteria, indictors that are being investigated include:
The indicators investigated ranged in their ability to predict the demise of the plants because of light stress. Contrary to expectation, PEA was not promising because of continuing acclimation by the plants to low light conditions. PEA is unlikely to be a suitable tool to measure sublethal chronic stress responses in seagrass. Leaf chlorophyll a was found to be a very sensitive measure of physiological changes in response to light deprivation, as has been indicated by previous researchers. We are investigating the utility of leaf reflectance spectra as a nondestructive technique to measure chlorophyll content in seagrass leaves.
A pilot experiment indicated that Zostera marina (eelgrass) potentially could tolerate up to 30-45 days of zero light conditions before 100 percent mortality occurred. The tropical species, Halodule wrightii (shoalgrass) however, experienced total mortality in less than 28 days. These interspecific differences in tolerance to light deprivation are complicated by the ability of different individuals to withstand light deprivation over a range of durations.
A second light-stress experiment was started in January 2003, to address the ability of leaf reflectance spectra to indicate physiological stress in seagrass plants at various stages of maturity grown under a range of limiting light conditions.
Field experiments also were commenced in early 2003, to establish links between water quality and seagrass survival under various conditions along the gradient of water quality that exists in North River. To date, results indicate that hydrodynamic regime may be more important than light availability in determining the success of seagrass in this estuary.
Future Activities:
Future activities include ongoing sampling throughout 2003 of water quality in both North River and Pamlico Sound to parameterize the optical indicator model being evaluated by Chuck Gallegos. Development of the indicator requires estimates of the mass-specific absorption and scattering coefficients of the suspended particulate matter from each of these locations. Cooperative efforts between the Atlantic Slope Consortium and the Atlantic Coast Environmental Indicators Consortium Estuarine and Great Lakes projects are being undertaken to develop a regionally extensive atlas of optical properties for broad geographic application of this indicator.
Testing and refinement of an in situ seagrass bioassay is underway to evaluate the effects of water quality on seagrass survival and growth. Plans for 2004 are to evaluate the performance of this method in the Chesapeake Bay to develop regional level confidence in the bioassay.
For the remainder of 2003, we will undertake light stress experiments on Zostera marina (eelgrass), the winter dominant species, and compare with Halodule wrightii (shoalgrass), the summer dominant species in North Carolina. These experiments are designed to determine minimum light requirements for these two species and evaluate potential indicator measurements. The results will be broadly applicable to seagrass habitats along the entire eastern seaboard of the United States.
Further refinement of leaf reflectance data as a noninvasive, nondestructive measure of chlorophyll content is being conducted. Destructive analyses of tissue samples to develop regressions for reflectance versus chlorophyll concentration is ongoing, and will provide the first data on this approach for both Zostera and Halodule spp.
Journal Articles:
No journal articles submitted with this report: View all 37 publications for this subprojectSupplemental Keywords:
seagrass, bio-optics, nutrients, bioindicators, conservation, environmental assets, scaling, aquatic, habitat, estuary, coastal, regionalization, integrated assessment, restoration, water quality and habitat management, remote sensing., RFA, Scientific Discipline, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, RESEARCH, estuarine research, Ecosystem/Assessment/Indicators, Ecosystem Protection, Ecological Effects - Environmental Exposure & Risk, Monitoring, Ecological Monitoring, Environmental Monitoring, Ecology and Ecosystems, Ecological Risk Assessment, Ecological Indicators, bioassessment, bioindicator, ecoindicator, remote sensing, aquatic biota , indicator plants, diagnostic indicators, ecosystem indicators, estuarine ecoindicator, estuarine ecosystems, aquatic ecosystems, environmental indicators, estuarine waters, seagrass photosynthesis, water quality, biogeochemistry, bio-optics, environmental stress indicatorsProgress and Final Reports:
Original AbstractMain Center Abstract and Reports:
R828677 Center for Integrating Statistical and Environmental Science 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
The 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.
Project Research Results
6 journal articles for this subproject
Main Center: R828677
385 publications for this center
90 journal articles for this center