Figure 9.3. Comparison of trends in the dominant foraminifer Elphidium for the past two millennia and the dominant ostracode Loxoconcha for the past 500 years in Chesapeake Bay. Records from core MD99-2209 and three piston cores from other regions from Cronin and others, (1999b; 2000) all show steep declines in the relative frequency of Elphidium and Loxoconcha sp. during the past two centuries due to human influences. The core from site PTXT-2 shows more frequent, high amplitude swings in these two taxa because this site is shallower (~12 m water depth versus 25-26 m) and therefore more sensitive to short-term fluctuations in salinity due to changes in fresh-water runoff. Foraminiferal analyses are based on ~100 individuals/sample; ostracode sample size ranges from 1 to >300 individuals and some sharp spikes in frequency are due to low abundance.

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