Microfossil study of Holocene aridity in the Great Lakes

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The Great Lakes Region is one of the most heavily populated in North America. A substantial fall in lake level would have a significant socioeconomic impact on this region, as it would affect navigation, water quality, aquatic and coastal ecosystems, and recreational use. There is evidence of a lowstand perhaps as much as 80 m below present lake levels in Georgian Bay in the not very distant past (around 8000 years ago), for instance, which appear to have been incorporated in the legends of the First Nations people of the region and passed down through the millenia. Because the onset of aridity is rapid, even in human time frames, and because agriculture and potable water supplies are greatly impacted (as evidenced in the "Dust Bowl" of the 1930's and the more recent near-disappearance of the Aral Sea), it is important to know the natural variability of precipitation and moisture availability in the Great Lakes region in order to anticipate the future and avoid unpleasant surprises. The fossil record of Great Lakes, and of small lakes in their drainage basins, record changes in aridity and lake level since the ice sheets retreated. Microfossils (pollen, and the remains of bottom-dwelling and planktonic lake-dwelling microorganisms) will be used to reconstruct paleoenvironments, and these data will be provided to modelers to assist them in producing accurate models of climate and lake level for this region. The improved understanding of the climate system, and how it produced (and responded to) arid conditions will be of global importance, since cold, arid conditions have been noted throughout the Northern Hemisphere around 8000 years ago.