Research Training ProgramSmithsonian
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| Molly J . Markey Bowling Green State University Bowling Green , Ohio Brian Huber, Ph.D. Supervising Scientist Department of Paleobiology "No matter how many times I was told, 'The Smithsonian has the largest/only collection of X in the world', the magnitude of resources available to me during this program never failed to amaze me." |
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Planktonic foraminifer assemblage and stable isotopic changes across the Aptian/Albian boundary oceanic anoxic event
ABSTRACT
Foraminifera are single-celled marine organisms that construct shells of calcium carbonate from minerals present in the ocean. Because foraminifera have short species durations and are sensitive to climatic change, analysis of fossil foraminiferal shells can be used to infer ancient ocean dynamics during a specific period of time. In this study, planktic foraminifera were used to discern the cause of a series of deep-sea global anoxic events across the Aptian/Albian boundary (113 million years ago). Anoxic events are thought to have been caused by 1) sea water stratification due to lack of ocean circulation, 2) an increase in surface level plankton productivity resulting in large amounts of organic material, which then sinks to the deep water and is broken down, using up all of the available oxygen; or 3) a combination of 1) and 2). Two methods were used to analyze samples taken from Ocean Drilling Program (ODP) deep-sea cores. First, stable oxygen and carbon isotope analyses were done to reconstruct changes in paleotemperature and ocean productivity, respectively. Second, counts of the number of individuals per species in each sample were done to look for changes in species abundance. A comparison of the species fluctuations and productivity and temperature changes determines if the anoxic events were caused by changes in the planktic foraminiferal population.
This research was supported by a grant from the National Science Foundation, Research Experiences for Undergraduates Program, award #EAR-9732416.