2000 Progress Report: Benthic Study Component

EPA Grant Number: R827072C007
Subproject: this is subproject number 007 , 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: Benthic Study Component
Investigators: Valentine, John F.
Institution:
EPA Project Officer: Packard, Benjamin H
Project Period: October 1, 1999 through September 30, 2000
Project Period Covered by this Report: October 1, 1999 through September 30, 2000
RFA: Alabama Center For Estuarine Studies (ACES) (1999) RFA Text |  Recipients Lists
Research Category: Ecological Restoration , Targeted Research

Objective:

Ecological systems, including soft sediment estuarine habitats, are dynamic and do not exist in undisturbed steady states indefinitely. The community patterns apparent on many marine landscapes are influenced by both natural (e.g., freshwater inflow) and anthropogenic disturbances (e.g., dredging or eutrophication). Such disturbances are common along the northern Gulf of Mexico and each has the potential to change the composition and structure of biological communities within all or a portion of this nationally important region. Of these, changes in fresh water inflow (i.e., a natural form of disturbance) appear to have the most dramatic impacts on the composition of communities in benthic habitats. During periods of high freshwater inflow, the benthic communities throughout the southeastern United States shift from speciose climax communities dominated by larger deeper burrowing organisms, to communities dominated by a comparatively limited number of shallow burrowing species (small-sized, irruptive, "r" selected species). These "r" selected species are short lived and have extraordinarily high rates of reproduction that result in large fluctuations in density at both seasonal and annual scales. Because of their shallow burrowing habitats, most of the "r-selected" species are easily accessible to small demersal fishes and crustaceans and represent a potentially important, and as yet inadequately investigated, link for the transfer of energy, nutrients and potentially sediment contaminants from benthic habitats to more mobile epibenthic predators.

The objectives for the benthic component of this study are to 1) correlate shifts in benthic community structure and secondary production with changes in other study components, 2) develop the first estimates of benthic secondary production (i.e., energy per unit area) from the northern Gulf of Mexico which will allow us to standardize comparisons of trophic interactions throughout the Mobile Bay, 3) assess the importance of physical resuspension processes (e.g., from bedload transport and storms) in controlling the availability of benthic organisms to predators, and 4) statistically compare these data with an existing historical data bases to develop a long term perspective on how benthic community structure changes in relation to seasonal and annual changes in hydrography and to establish a baseline from which to formulate hypotheses which will be used to determine how energy (i.e., secondary production) flows from benthic communities to higher order consumers.

Progress Summary:

Sorting of benthic samples was not begun until of October of 2000. Even so, we have almost completed the sorting of five of the twelve months of samples that were collected (Objectives 1 & 2). One unanticipated hurdle that we have had to address is the degree to which many of the polychaetes have been fragmented. Since one of the major goals of this effort is to provide the first estimates of benthic biomass production in the Gulf of Mexico (Objective 2), we have switched from sorting samples under illuminated magnifying glasses to sorting with dissecting microscopes. In addition to the sorting, we have completed rough identification of samples from three of the months (see attached for the initial assessments of the composition and relative abundance of benthic taxa). We have also completed entry of data from existing historical databases plus river gage data from the Mobile River (Objective 4). We have also conducted exploratory analyses of these historical databases (Objective 4). We have not proceeded with estimates of biomass production, as wet lab construction has not yet been completed.

Inspection of the data analyzed to date suggests that although the relative abundance of macroinvertebrates can vary over time, polychaetes and molluscs dominate benthic community (see attached figures). Crustaceans and echinoderms seem to contribute little in terms of density to benthic community structure. This pattern is similar to what we have seen in the initial inspection of the historical data. Estimates of density from samples collected to date also seem to be in line with the earlier estimates.

attached figures

attached figures

attached figures

Supplemental Keywords:

estuarine research, coastal ecosystem, eutrophication, benthic study, human modifications, land and water use, watersheds, aquatic ecosystems, anthropogenic stress, Gulf of Mexico., RFA, Scientific Discipline, Geographic Area, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, estuarine research, Ecosystem/Assessment/Indicators, Ecosystem Protection, Chemistry, Restoration, Aquatic Ecosystem, Ecological Effects - Environmental Exposure & Risk, Aquatic Ecosystems, Ecological Effects - Human Health, Ecological Monitoring, Ecology and Ecosystems, Aquatic Ecosystem Restoration, Gulf of Mexico, Ecological Indicators, coastal ecosystem, wetlands, anthropogenic stress, eutrophication, water use, anthropogenic stresses, Mobile Bay, estuaries, watersheds, coastal environments, wetland stabilization, ecosystem, environmental indicators, estuarine waters, water quality, human modifications, land use

Progress and Final Reports:

Original Abstract
  • 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