2000 Progress Report: Effects of Variation in River Discharge and Wind-Driven Resuspension on Higher Trophic Levels in the Mobile Bay EcosystemEPA Grant Number: R827072C005
Subproject: this is subproject number 005 , 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: Effects of Variation in River Discharge and Wind-Driven Resuspension on Higher Trophic Levels in the Mobile Bay Ecosystem
Investigators: Cowan, James H.
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:The focus of this study involving 3 P.I.'s (Cowan, Graham and Valentine) is on higher trophic levels in Mobile Bay (Bay), (i.e. on benthic invertebrates, macrozooplankton and forage fishes). Quantification of community biomass production and consumption at each of these trophic levels, and evaluation of how production and consumption rates respond to freshwater inputs and sediment resuspension (and their associated affects on the input of nutrients) forms the main body of our research. One of the major objectives is to provide estimates of the amount of biomass (hence carbon) which is transferred from one consumer level to the next, and how this varies spatially and temporally within the Bay. Complimentary investigations by other Program colleagues (a second proposal by Kiene, Pennock, and Cowan) is focusing on the base of the food chain (the microbial loop and phytoplankton), thus providing estimates of the biomass available to higher trophic levels.
Progress Summary:Biological samples and descriptive physical-oceanographic data in year 1 have been collected on 1 day cruises each month at 3 fixed stations, including 1 station each in three hydrographic regimes in Mobile Bay (see proposal for details). The goal of first year sampling was to describe "regional baseline" conditions in trophic dynamics. In year two, sampling will occur at the same three stations, but at the "event" temporal scale, such that sampling will be focused on two distinct resuspension events. Our plan is to sample 2 days before, during, two days after, and 5 days after a wind-driven resuspension event. The timing of sampling in year two will depend on weather patterns and cold front passages, but our intent is to sample two events in March 2001, or 1 each in March and April, 2001. Northerly winds in excess of 10 m-1 associated with cold front passages have been shown to result in significant sediment resuspension (>5.1 x 106 kg net TSS flux) in Fourleague, LA . We will thus try to target events that are expected to generate similar wind speeds on Mobile Bay.
Analysis of the biomass production data has begun, but is thus far based only upon partial otter trawl collections. Bay anchovy is the most abundant fish present at all three stations, with peaks in density in the lower Bay of 6.89 to 11.10 fish/10m2 occurring in July and August, respectively. On average, anchovy density is highest in the lower Bay, but the highest monthly mean density for any station (26.15 fish /10m2) was observed in the upper Bay. Atlantic croaker and spot monthly mean density is less than for bay anchovy, and appears to be strongly influenced by the shrimp fishery in the Bay. Mean densities of both peaked just prior to the beginning of shrimp season in June (at ~1.5 to 2.0 fish 10m2 for croaker, ~0.40 fish/m2 for spot), then declined precipitously. In combination, the target forage fish species (bay anchovy, Atlantic croaker, spot and Gulf menhaden) account for > 70 % of the total biomass of fish collected. Diet analysis of the target species has begun for individuals collected in both otter and mid-water trawls at all stations. Preliminary analysis suggests that major diet shifts in all species occur during resuspension events. Similar, data also have been collected for decapod crustaceans, including blue crabs, white and brown shrimp. We are attempting to use RNA:DNA ratios to determine the effects of resuspension events on shrimp growth rates.
Supplemental Keywords:estuarine research, coastal ecosystem, watersheds, aquatic ecosystems, river discharge, nutrients, trophic levels, biomass., RFA, Scientific Discipline, Geographic Area, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Chemical Engineering, Aquatic Ecosystems & Estuarine Research, estuarine research, Environmental Chemistry, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Chemistry, Restoration, Aquatic Ecosystem, Ecological Effects - Environmental Exposure & Risk, Aquatic Ecosystems, Ecological Effects - Human Health, Ecology and Ecosystems, Ecological Risk Assessment, Aquatic Ecosystem Restoration, Gulf of Mexico, Ecological Indicators, river discharge, trophic levels, coastal ecosystem, water use, Mobile Bay, estuaries, watersheds, nutrients, biomass, ecosystem, estuarine waters, water quality
Progress and Final Reports:Original Abstract
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