2002 Progress Report: Holocene Sedimentary History of Weeks Bay, AL: Human and Natural Impacts on Deposition in a Gulf Coast Estuary

EPA Grant Number: R827072C026
Subproject: this is subproject number 026 , 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: Holocene Sedimentary History of Weeks Bay, AL: Human and Natural Impacts on Deposition in a Gulf Coast Estuary
Investigators: Haywick, Douglas , Allison, David , Blackwell, Keith , Clark, Murlene , Fearn, Miriam , Isphording, Wayne , Kempton, John , Yokel, Lee
Institution: University of South Alabama
EPA Project Officer: Packard, Benjamin H
Project Period: January 1, 1999 through December 31, 2002 (Extended to June 30, 2003)
Project Period Covered by this Report: January 1, 2001 through December 31, 2002
RFA: Alabama Center For Estuarine Studies (ACES) (1999) RFA Text |  Recipients Lists
Research Category: Targeted Research


Marginal marine environments such as estuaries, lagoons, and bays are important repositories for fine-grained sedimentation. As such, they provide unrivalled records by which to resolve depositional processes that operate in coastal environments, climatic change, and Holocene (e.g., less than 10,000 years BP) oscillations at sea level. This project examines the recent sedimentary record preserved within Weeks Bay, a small estuary in southwestern Alabama. The specific objectives of this research project are to: (1) characterize Holocene stratigraphy of sediment fill in Weeks Bay; (2) document the sedimentology of Weeks Bay sediment to gauge the relative importance of storms, marine, and fluvial processes as sedimentation mechanisms in Weeks Bay; (3) determine the biostratigraphy of Weeks Bay using diatoms, pollen, and foraminifera; and (4) assess geochemical levels of Cd, Zn, and Hg in Weeks Bay bottom sediment.

Information gained from the various components of this research project will be of use to scientists interested in the geology and ecology of northern Gulf of Mexico coastal embayments. It also will prove useful to individuals interested in the interplay between natural and human-induced impacts in sensitive coastal environments.

Progress Summary:


This project is in the final data processing stage, and is approximately 6 months away from completion. It was necessary to apply for a no-cost extension to process the enormous amount of sedimentological and biological data that were collected over the 3-year timespan of the study.

Principle sampling was conducted using a simple piston coring device. We collected 17 cores up to 4.5 m in length from Weeks Bay during field sessions in 1999, 2000, and 2001. The cores were obtained from one north-south (7 cores) transect and two east-west (10 cores) transects. After extraction, each core was examined for variations in stratigraphy, mineralogy, grain size, and when possible, faunal content. Samples were extracted for grain size, analysis at either a 1-cm or a 3-cm scale in all 17 cores. More than 1,800 individual grain size analyses were conducted by the Principal Investigator (PI) and undergraduate geology research students during the course of the study. Two representative cores also were examined for pollen content and 137Cs isotopic markers. Two other cores were subsampled to provide a detailed record of sedimentation rates using conventional 14C dating. Radiocarbon dating also was employed to establish bottom dates for all cores.

Cores collected proximal to shorelines were dominated by sandy silt and quartz sand, and they preserved a record of high energy, shoreface deposition. Two of the cores bottomed out at a peaty-limonitic clay that contained large quartz pebbles up to 2 cm in diameter. We interpret this interval as a transgressive lag formed during the final phase of Holocene sea level rise (circa 6,000 years, B.P.).

Cores collected from central portions of the bay consisted primarily of bioturbated, blue-grey, claylike-silt, the typical fair-weather sediment that presently is being deposited in low-energy areas of Weeks Bay. Some of the cores displayed coarsening upward or fining-upward variations, the results of predictable facies shifts. The majority of the central Weeks Bay cores also contained sporadic, thin layers (< 1 cm) of fine to medium sand, which we interpret as episodic storm or flood events.

Sandy intervals rarely contained any organic detritus, but finer grain sizes contained diatoms, shell fragments, pollen, and abundant comminuted plant detritus. Foraminifera have not been observed in any of the cores collected in this study. Bottom 14C dates were variable with depth of penetration, but ranged between 2,000 years B.P. and 6000 years B.P. These data, in conjunction with additional radiocarbon dates derived from deeper boreholes (Kempton, personal communication), are being used to establish the complete Holocene stratigraphy of the Weeks Bay area.

Biostratigraphic analysis of a core from the central part of Weeks Bay (Core IX) is essentially complete. More than 150 diatom species have been identified. Several diatoms remain unidentified by the international diatom community and may be totally new species. Several pollen samples have been recounted as part of the quality assurance plan. Overall, there is little variation in pollen percentages throughout the core. Pinus (pine) and Quercus (oak) dominate, and Taxodium (cypress) is the main wetland tree.

Core IX has 3 distinct zones delineated by grain size, organic content, pollen concentration, diatom assemblages, and Cesium-137 activity. The top 70 cm has higher sand content, higher organic content, lower pollen concentrations, smaller diatoms, more freshwater diatoms, and the presence of Cesium-137. Evidence suggests post-1950 sediments (or mixing), significant riverine influence, high sedimentation rates, and eutrophication. From 70 to approximately 140 cm, sediments are less sandy, organic content drops, pollen concentrations (especially pine) are significantly higher, freshwater diatoms are rare, and Cesium-137 disappears. High pine pollen concentrations can be associated with low sedimentation rates for clastic material or significant transport by water because pine pollen floats readily. Diatom evidence supports the transport scenario, not low sedimentation rates. The lower part of the core has higher clay content, lower organic content, similar pollen concentration to the top 70 cm, and more marine diatoms. The lower zone is clearly presettlement. Pollen counting on Core I yielded similar results.


Masters candidate Chuck Stapleton is in the final stages of data processing (diatoms), and he is scheduled to submit his thesis for examination in mid-2003. He attended the Iowa Lakeside Lab diatom class during the summer of 2002 as an assistant. In addition to Stapleton’s research, many undergraduate students majoring in geology, geography, and biology have had their directed research projects supported through this grant. Apart from the opportunity to conduct hands-on research in the field and the laboratory, several students have authored presentations for professional meetings. This year, Chuck Stapleton presented his work at the International Diatom Symposium in Ottawa, Canada. Stephanie Capello (Geology) presented parts of her research at the Geological Society of America Meeting in Denver, and she was approached to submit a paper to the CUR Quarterly, a respected journal published by the Council on Undergraduate Research. Her paper is scheduled to be submitted for review in March 2003.

Future Activities:

This project is scheduled for completion by June 2003. Until that time, data will be processed. The Web site, which will include a data repository, is in the initial planning stages.

Project Investigators, Haywick and Fearn have proposed a topical session on estuarine sedimentation and ecology for the 2003 National Meeting of the Geological Society of America to be held in Seattle, WA, in October. If successful, the session will allow us to share our research from the Gulf Coast of Alabama with scientists studying similar environments in other parts of the world. In addition, two papers on the sedimentology of Weeks Bay are in preparation (Haywick), as well as one on the paleoecology (Fearn). Mr. Stapleton’s diatom research has yielded several new species that will necessitate at least one important paper from his Masters thesis.

Journal Articles:

No journal articles submitted with this report: View all 5 publications for this subproject

Supplemental Keywords:

Holocene stratigraphy, sedimentology, storms, marine, fluvial processes, sedimentation mechanisms, biostratigraphy, diatoms, pollen, foraminifera, geochemical levels, fine-grained sedimentation, coastal environments, climatic change, Holocene oscillations, radiocarbon dating, peaty-limnotic clay, quartz pebbles, organic detritus, Pinus, pine, Quercus, oak, Taxodium, cypress, pine pollen, ecological effects, ecological indicators, environmental exposure, geographic area, water, aquatic ecosystem, coastal ecosystem, coastal environments, estuary, estuaries, estuarine research, estuarine waters, environmental chemistry, chemistry, risk, assessment, indicators, human health, Alabama, AL Region 4., RFA, Scientific Discipline, Air, Geographic Area, ECOSYSTEMS, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Aquatic Ecosystems & Estuarine Research, estuarine research, Ecosystem/Assessment/Indicators, Ecosystem Protection, Restoration, climate change, Air Pollution Effects, Aquatic Ecosystem, Aquatic Ecosystems, Ecological Effects - Environmental Exposure & Risk, Terrestrial Ecosystems, Ecological Monitoring, Ecological Risk Assessment, Aquatic Ecosystem Restoration, Atmosphere, Gulf of Mexico, Ecological Indicators, coastal ecosystem, river discharge, trophic levels, environmental monitoring, Mobile Bay, estuaries, watersheds, nutrients, biomass, phytoplankton, ecosystem, environmental indicators, estuarine waters, water quality, wind-driven resuspension, sediment dynamics

Relevant Websites:

http://www.southalabama.edu/aces/ Exit
http://www.usouthal.edu/geography/haywick/weeksbay.htm Exit

Progress and Final Reports:

Original Abstract
  • 1999
  • 2000
  • 2001
  • 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