2002 Progress Report: The Influence of Shallow Water Hydrodynamics on the Importance of Seagrass Detritus in Estuarine Food Webs

EPA Grant Number: R827072C035
Subproject: this is subproject number 035 , established and managed by the Center Director under grant R827072
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Alabama Center For Estuarine Studies (ACES)
Center Director: Shipp, Robert L.
Title: The Influence of Shallow Water Hydrodynamics on the Importance of Seagrass Detritus in Estuarine Food Webs
Investigators: Valentine, John F. , Cinkovich, Anna M.
Institution: University of South Alabama
EPA Project Officer: Packard, Benjamin H
Project Period: July 1, 2001 through May 31, 2002 (Extended to December 31, 2003)
Project Period Covered by this Report: July 1, 2001 through May 31, 2002
RFA: Alabama Center For Estuarine Studies (ACES) (1999) RFA Text |  Recipients Lists
Research Category: Targeted Research


The objectives of this research project are to: (1) identify and characterize the hydrodynamic conditions that control the export of Thalassia testudinum and Halodule wrightii detritus from source beds and their subsequent deposition in nearby unvegetated areas; (2) determine the persistence of these small patches of accumulated T. testudinum and H. wrightii under natural conditions; (3) estimate the amount of T. testudinum and H. wrightii detrital export from source beds in Perdido Bay; and (4) determine the degree to which the shallow water benthic community of Perdido Bay is controlled by small-scale accumulations of T. testudinum and H. wrightii.

Progress Summary:

The first objective of this has been met. We completed the laboratory (flume) experiments and have developed the predictive criteria that will be used to understand the role of hydrodynamic processes in controlling the spatial distribution of seagrass detritus accumulations in a shallow water seagrass-sandflat mosaic.

The second objective of this study also has been completed. Results show that water depth, storm events, and anthropogenic effects such as boat wakes can significantly shorten the persistence of most detrital accumulations; however, under certain conditions, patches can persist for several weeks (see Figure 1). This indicates that patches occasionally persist long enough to be a source of food and/or shelter for organisms outside of living seagrass beds. Thus, these patches likely represent an important, and as yet unconsidered, direct link between seagrass beds and mud/sand flat habitats, and this linkage must be considered during the development and implementation of coastal management practices.

The third objective of this project also is complete; field experiments were conducted approximately every 6 weeks from August 2001 through July 2002. The following became apparent during these field experiments: (1) the sampling methods were effective; they captured seasonal changes in detrital export such as the winter seagrass dieoff; (2) prevailing winds, even at low speeds, have a large influence on the distribution of seagrass detritus within the study site; and (3) storm events play an important role in seagrass detritus export and distribution.

Figure 1. Persistence of Stingray Pits in Big Lagoon

The fourth objective of this project also has been completed through field experiments, which were concluded in July 2002. This project originally was proposed to be conducted from April 2001 to April 2002. However, the project startup was delayed as funds to conduct the study were not obligated until July 2001. As a result, data collection began in August 2001 and continued until August 3, 2002.

Future Activities:

A manuscript presenting the findings of our first objective is in progress, and it will be submitted for publication in summer 2003.

The findings of our second objective will be incorporated into the findings of the other objectives as manuscripts are prepared for publication.

All of the experimentation necessary to meet the third and fourth objectives of this study has been completed, and the samples collected during these experiments currently are being processed. Because of the large number and time-consuming nature of these samples, we anticipate that sample processing will continue through March 2003. Manuscripts that present the findings of these objectives will be submitted for publication by the end of August 2003.

Supplemental Keywords:

anthropogenic effects, marine, population, public policy, decisionmaking, conservation, environmental assets, biology, modeling, Gulf Coast, Alabama, AL, Florida, FL, Thalassia Testudinum, Halodule writti, Perdido Bay, benthic community, ecosystem, ecosystem protection, ecology, ecological effects, ecological indicators, ecosystem indicators, water, aquatic ecosystem, coastal ecosystem, coastal environments, estuary, estuaries, estuarine research, estuarine waters, environmental chemistry, chemistry, risk, assessment, indicators, Alabama, AL, human modifications., RFA, Scientific Discipline, ECOSYSTEMS, Water, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, Ecology, estuarine research, Ecosystem/Assessment/Indicators, Restoration, Aquatic Ecosystem, Aquatic Ecosystems, Ecological Monitoring, Ecology and Ecosystems, Aquatic Ecosystem Restoration, coastal ecosystem, eutrophication, water use, nursery habitats, estuaries, fish, watersheds, nutrients, biomass, fisheries, aquatic plants, algal blooms, submerged aquatic vegetation, ecosystem, environmental indicators, water quality, estuarine waters, hydrodynamics, estuarine food web, human modifications, seagrass

Relevant Websites:

http://www.southalabama.edu/aces/ Exit

Progress and Final Reports:

Original Abstract
  • 2003
  • Final

  • Main Center Abstract and Reports:

    R827072    Alabama Center For Estuarine Studies (ACES)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R827072C001 Fluorescent Whitening Agents As Facile Pollution Markers In Shellfishing Waters
    R827072C002 Red Snapper Demographics on Artificial Reefs: The Effect of Nearest-Neighbor Dynamics
    R827072C003 Stabilization of Eroding Shorelines in Estuarine Wave Eliminates with Constructed Fringe Wetlands Incorporating Offshore Breakwaters
    R827072C004 Interaction Between Water Column Structure and Reproduction in Jellyfish Populations Of Mobile Bay (SGER)
    R827072C005 Effects of Variation in River Discharge and Wind-Driven Resuspension on Higher Trophic Levels in the Mobile Bay Ecosystem
    R827072C006 Results of Zooplankton Component
    R827072C007 Benthic Study Component
    R827072C008 A Preliminary Survey of Macroalgal and Aquatic Plant Distribution in the Mobile Tensaw Delta
    R827072C009 Fisheries-induced changes in the structure and function of shallow water "nursery habitats": an experimental assessment
    R827072C010 Effects Of Variation in River Discharge and Wind-Driven Resuspension on Lower Trophic Levels of the Mobile Bay Ecosystem
    R827072C011 Evaluation of Alabama Estuaries as Developmental Habitat for Juvenile Sea Turtles
    R827072C012 Effects of Salinity Stress on Natural and Anthropogenically-Derived Bacteria in Estuarine Environments
    R827072C013 The Role of Land-Use/Land-Cover and Sub-estuarine Ecosystem Nitrogen Cycling in the Regulation of Nitrogen Delivery to a River Dominated Estuary; Mobile Bay, Alabama
    R827072C014 Environmental Attitudes of Alabama Coastal Residents: Public Opinion Polls and Environmental Policy
    R827072C015 Synthesis and Characterization of an Electrochemical Peptide Nucleic Acid Probe
    R827072C016 Determinants of Small-Scale Variation in the Abundance of the Blue Crab Callinectes Sapidus
    R827072C017 Effects of Estrogen Pollution on the Reproductive Fitness of the Gulf Pipefish, Syngnathus scovelli
    R827072C019 A Model for Genetic Diversity Aquatic Insects of the Mobile/Tensaw River Delta
    R827072C020 Evaluating Trophic Processes as Indicators of Anthropogenic Eutrophication in Coastal Ecosystems: An Exploratory Analysis
    R827072C021 Effects of Anthropogenic Eutrophication on the Magnitude and Trophic Fate of Microphytobenthic Production in Estuaries
    R827072C022 Characteristics of Ship Waves and Wind Waves in Mobile Bay
    R827072C023 Methods Comparison Between Stripping Voltammetry and Plasma Emission Spectroscopy for Metals in Mobile Bay
    R827072C024 Changes in Water Conditions and Sedimentation Rates Associated With Construction of the Mobile Bay Causeway
    R827072C025 Cold-Induced Hibernation of Marine Vibrios in the Gulf of Mexico: A Study of Cell-Cell Communication and Dormancy in Vibrio vulnificus
    R827072C026 Holocene Sedimentary History of Weeks Bay, AL: Human and Natural Impacts on Deposition in a Gulf Coast Estuary
    R827072C027 Shelter Bottlenecks and Self-Regulation in Blue Crab Populations: Assessing the Roles of Nursery Habitats and Juvenile Interactions for Shelter Dependent Organisms
    R827072C028 Predicting Seagrass Survival in Nutrient Enriched Waters: Toward a New View of an Existing Paradigm
    R827072C029 DMSP and its Role as an Antioxidant in the Salt Marsh Macrophyte Spartina alterniflora
    R827072C030 A Preliminary Survey of Aerial and Ground-Dwelling Insects of the Mobile/Tensaw Delta
    R827072C031 Natural Biogeochemical Tags of Striped Mullet, Mugil cephalus, Estuarine Nursery Areas in the North Central Gulf of Mexico
    R827072C032 Resolution of Sedimentation Rates in Impacted Coastal Environments Using 137Cs and 210Pb Markers: Dog River and Fowl River Embayments
    R827072C033 Investigation of the Use of Pulse Amplitude Modulated (PAM) Fluorometry as an Indicator of Submerged Aquatic Vegetation Health in Mobile Bay
    R827072C034 Influence of Invasive Plant Species in Determining Diversity of Aquatic Vegetation in the Mobile-Tensaw Delta
    R827072C035 The Influence of Shallow Water Hydrodynamics on the Importance of Seagrass Detritus in Estuarine Food Webs
    R827072C036 Food Web Interactions, Spatial Subsidies and the Flow of Energy Between the Mobile Bay Delta and Offshore Waters: A SGER Proposal to the Alabama Center for Estuarine Studies
    R830651C001 Meteorological Modeling of Hurricanes and Coastal Interactions: A Stability Study For Vertical Pressure Levels
    R830651C002 Characterization of Glycoprotein Cues Used by the Parasitic Rhizocephalan Barnacle Loxothylacus texanus To Identify Its Blue Crab Host, Callinectes sapidus
    R830651C003 Survey of Diamondback Terrapin Populations in Alabama Estuaries
    R830651C004 An Assessment of Environmental Contaminant Levels in Water and Dragonfly Larvae Tissues from the Mobile/Tensaw Delta