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Phytoplankton 
        Record of Chesapeake Bay Water Quality - A Holocene Perspective: Matthew R. Wright
Project Title: Phytoplankton Record of Chesapeake Bay Water Quality: A Holocene Perspective
Mendenhall Fellow: Matthew R. Wright, (703) 648-6071, mrwright@usgs.gov
Duty Station: Reston, VA
Start Date: March 14, 2005
Education: Ph.D. (Marine Geology) The University of Durham, UK. 2005
Research Advisor: Debra A. Willard, (703) 648-5320, dwillard@usgs.gov
  Matt Wright

Project Description: The combined influences of natural climate variability, relative sea-level changes and anthropogenically induced ecosystem degradation create considerable problems for the management and potential remediation of coastal ecosystems and environments. It is therefore critical that we endeavour to understand how individually these influences control changes in coastal ecosystems and environments so as to be better able to undertake their management and remediation.

Recent research in the estuarine system of Chesapeake Bay (Willard et al., 2003; Cronin et al., 1999; 2000; 2003; Colman et al., 2002) has demonstrated that the sediment cores retrieved from the bay have preserved within them an excellent proxy record of late Holocene (circa last 2300 years) palaeoclimate over decadal (Cronin et al., 2000) to millennial (Willard and Korejwo, 2000) timescales in the region, as well as a record of local ecosystem variability during this time. However as yet there is a paucity of longer-term Holocene (last 10000 years) records of climate and ecosystem changes for the region. The longer-term understanding of these phenomena is essential if we are to disentangle a) the human induced changes in the environment, and b) the supposed anthropogenic forcing of the climate system, from natural variability.

Similarly during the last 100 years, tide gauge records have shown acceleration in the rate of eustatic sea-level rise compared with longer term trends. However, it is uncertain whether this recent sea-level rise began before or after industrial carbon dioxide emissions, or whether this acceleration is a remnant of longer-term climatic changes. Therefore both the historical (tide gauge) and future sea-level projections (e.g., IPCC) must be placed in a longer-term (the last one to ten thousand years) context. The key to improving this is to undertake high-resolution sea-level reconstructions from critical locations (i.e. the eastern coast of the United States).

This research project outlines a strategy to undertake new and detailed integrated lithostratigraphic, palaeoenvironmental and geochronological investigations in Chesapeake Bay utilising new and innovative tools available to coastal research. These data will then be applied to improve the understanding of Holocene, modern and future sea-level change along the United States eastern seaboard, as well as potentially providing detailed information into climate variability, and the nature and scale of eutrophication, anoxia, sediment influx, water clarity and spring runoff (precipitation) in Chesapeake Bay during the same period.


References
Colman, S.M., Baucom, P.C., Bratton, J.F., Cronin, T.M., McGeehin, J.P., Willard, D.A., Zimmerman, A.R. and Vogt, P.R., (2002) Radiocarbon dating, chronological framework, and changes in accumulation rates of Holocene estuarine sediments from Chesapeake Bay. Quaternary Research. 57, 58-70.

Cronin, T.M., Colman, S.M., Willard, D.A., Kerhin, R., Holmes, C., Karlsen, A., Ishman, S. and Bratton, J. (1999) Interdisciplinary environmental project probes Chesapeake Bay down to the core. EOS, Transactions of the American Geophysical Union. 80, 237, 240-241.

Cronin, T.M., Willard, D.A., Karlsen, A., Ishman, S., Verardo, S., McGeehin, J., Kerhin, R., Holmes, C., Colman, S.M. and Zimmerman, A. (2000) Climatic variability in the eastern United States over the past millennium from Chesapeake Bay sediments. Geology. 28, 3-6.

Cronin, T.M., Dwyer, G.S., Kamiya, T., Schwede, S. and Willard, D.A. (2003) Medieval Warm Period, Little Ice Age and 20th century temperature variability from Chesapeake Bay. Global and Planetary Change. 36, 17-29.

Willard, D.A. and Korejwo, D.A. (2000) Holocene palynology from Marion-Dufresne cores MD99-2209 and 2207 from Chesapeake Bay, impacts of climate and historic land-use change. In: Cronin, T.M. (Ed.) Initial report on IMAGES V cruise of the Marion-Dufresne to Chesapeake Bay June 20-22, 1999. US Geological Survey Open-File Report 00-306, 78-86.

Willard, D.A., Cronin, T.M. and Verardo, S. (2003) Late-Holocene climate and ecosystem history from Chesapeake Bay sediment cores, USA. The Holocene. 13, 201-214.


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