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Sedimentary Record of pelagic fish abundances and coastal upwelling variability on the west coast of Vancouver Island |
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We are currently reconstructing the middle and late Holocene climate of coastal BC by examining the sedimentary record of Effingham and Seymour Inlets, anoxic basins wherein finely laminated sediments are well preserved. A combination of sedimentological, micropalaeontological. geochemical and geophysical measurements along 2 long piston cores collected in Effingham Inlet from the R/V Marion Dufresne in 2002 and a single piston core in Seymour Inlet from the CCGS Vector in 2003 will enable us to study changes in terrestrial climate, ocean sea surface temperature, upwelling, production, nutrient utilization and fish abundances over the last 10,000 years. In this way we hope to be able to identify the forcing of atmospheric and surface ocean changes by natural climate and oceanographic cycles prior to the 100-year instrument record that is currently available. |
last updated October 25, 2004
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Natural climate variability must be understood if reliable predictions of future climate states are to be made. Geological and historical records from coastal B.C. provide clear evidence that the regional climate has oscillated on a variety of scales during the Holocene interglacial. The present climate of the west coast of Canada is influenced by the Aleutian Low, the Jet Stream, and El Niño/La Niña, which are interdependent and have sub-decadal cycles. Superimposed in these are less well understood, longer-scale events operating on a global scale. The interactions of these climate-forcing phenomena determine whether there will be costly droughts or flooding on land, and influence recruitment rates in many BC fisheries. The purpose of this research is to assess the individual and combined effects of these climate-forcing phenomena on the primary biological productivity of the marine ecosystem throughout coastal British Columbia. This information is critical for policy makers attempting to recognize anthropogenic climate change. Recognition of the natural climatic cycles affecting the coastal ocean will also enable the commercial marine fishing industry to respond more strategically to natural variations in fish stocks.