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Seminar Abstract

Russel Barsh, Research & Archives, Samish Indian Nation - February 11, 2003


Climate and anthropogenic factors in ancient red tides: distinguishing causal factors in Puget Sound paleoecology

An emerging area of climate research has been the role of ocean warming in triggering harmful algal blooms (HABs) or "red tides". A recent study of deep sediment cores in British Columbia suggested that HABs have occurred in the Puget Sound-Georgia Strait basin for millennia, strongly associated with long term warming trends. However, the pattern of blooms appears to have changed, particularly over the past 2000 years. Could the growth of aboriginal human societies, based on increasingly efficient salmon fishing methods, explain these changes? As a general methodological issue, can paleoclimate researchers distinguish environmental and human forcing of ecosystem changes? An evolving research program will be described using a combination of archaeology and sediment core analyses to investigate the respective roles of climate and human redistributions of nutrients (fish to garbage) in triggering local HABs events in pre-1800 Puget Sound.

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