Activities
1) Geological field work
Students will measure stratigraphic sections and collect bulk samples from the fossil record spanning the Plio-Pleistocene extinction and recovery intervals in North and South Carolina.
2) Geological sample processing
Samples will be processed using standard sedimentological and paleontological techniques. Samples will be sieved, macrofossils picked, separated into species, and identified. Grain-size analysis of the sediment will be conducted and a representative sample of microfossils will be picked and identified.
3) Environmental interpretation
Environmental context will be inferred based on field observations of the stratigraphic sections and sedimentological and microfossil analysis.
4) Ecological analyses for the fossil assemblages
Abundance data will be collected for each mollusc species and different approaches to examining abundance structure will be used. Various diversity metrics will be calculated. Community composition with respect to life habits and trophic category will be examined; changes in trophic structure can indicate declines in productivity.
5) Ecological interactions
The history of specific ecological interactions will be determined using the trace fossil record (e.g., drillholes from predatory gastropods or octopods, characteristic breakage and/or repair patterns due to crustaceans, gastropods, fish and other predators). Because the capacity for predator-prey systems to evolve is thought to be influenced by the availability of resources, tracking such systems can provide information on natural and anthropogenic habitat modification and the effect on communities.
6) Geochemical work
Geochemical proxies, including the stable isotope record preserved in mollusc shells, are useful in assessing climate and productivity regimes (which can then be connected to patterns in diversity and ecology). For this aspect of the study, students will learn to sample shells for isotopic analysis. These samples will be analyzed for oxygen isotopes at the IRMS lab at CMS.
7) Archeological work
The primary goal of the archeological work is to demonstrate the applicability of archeology to biodiversity conservation using material from North Carolina shell middens. The same geochemical techniques applied to fossil materials will be used on shells from middens to provide information on climate and harvesting practices (season of death of shellfish). In addition, material from shell middens can provide information on trophic interactions and the degree to which ecosystems have been affected by humans.
8) Modern assemblages
To assess the health of the modern community, samples will be derived from a variety of habitats (e.g., salt marsh, oyster reefs, sand bottom, and sea grass environments) using core and quadrat sampling for intertidal sites and grab samples for subtidal areas. Sampling a variety of sites will allow students to compare ecosystems that vary in their degree of anthropogenic impact based on analyses of diversity, abundance, trophic structure, and species
interactions.
9) Experiments with live animals
Experiments will be conducted at the Center for Marine Science to enable students to observe interactions among taxa.Students can observe predation traces of particular predators “in the making” and enable them to recognize them in the fossil and archeological record.
10) Synthesis of results and discussion of environmental management implications
Baseline data from the fossil and archeological records of the Carolinas will be compared with 1) data from other geographic regions (Florida and Panama), and 2) modern environments exhibiting different degrees of human impact. These comparisons will allow characterization of variation in regional responses of systems to natural stresses, assessment of the health of modern ecosystems, and identification of specific problems associated with anthropogenic ecosystem modification.
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