Understanding Links Between Climate and Marine Ecosystems in the Northeast Pacific

Bruce P. Finney

Institute of Marine Science

University of Alaska Fairbanks

Fairbanks AK 99775

Finney@ims.uaf.edu

Phone: (907) 474-7724; Fax: (907) 474-7204

Historical records of air and ocean temperature, as well as atmospheric pressure fields, show significant interdecadal fluctuations (i.e., PDO) in the North Pacific region. These climatic fluctuations appear to have had large impacts on marine ecosystems, as records of abundance and/or species assemblages of zooplankton, fishes, seabirds and marine mammals correlate with indices of North Pacific climate (Mantua et al., 1997). For example, salmon catch records suggest a correlation between the intensification of the Aleutian Low, increased coastal sea surface temperatures in the eastern North Pacific, and increased production of Alaskan salmon during the 20^th century. Monitoring of primary and secondary production in the Northeast Pacific, though limited, suggests that climatic forcing has a direct impact on lower trophic levels, which subsequently affects salmon production. Drilling in the coastal Gulf of Alaska region can provide an unprecedented opportunity to better establish links between climate, ocean processes and marine ecosystems on a wide range of timescales. Such information is important because of the large economic, ecological and cultural importance of marine resources in this region. High-resolution (sub-decadal) paleoceanographic records, easily obtainable, can fill in data gaps not covered by historical monitoring. Longer paleoceanographic records can be compared to reconstructions of salmon abundance obtained from coastal lakes (see Finney et al. 2000 for methods). Salmon abundance over the last ~300 years in the northern Gulf of Alaska varied strongly on mutlidecadal timescales, similar to historical observations (Finney et al. 2000). Records over the last ~2000 years suggest dramatic shifts in abundance which far exceed the decadal-scale variability recorded during the past 300 years (Finney et al. 2002). Current research suggests significant changes in salmon abundance corresponding to the major periods of Holocene climatic variability (e.g., Neoglaciation) in this region. The paleoceanographic records from cores obtained by drilling in the Gulf of Alaska can be correlated into these records using AMS radiocarbon dating, tephrachronology and paeolmagnetic variations. Such comparisons should greatly expand current knowledge on links between North Pacific climatic and marine ecosystems, and the timescales of natural variability.

References

Finney, B.P., Gregory-Eaves, I., Sweetman, J., Douglas, M.S.V. and Smol, J. (2000). Impacts of Climatic Change and Fishing on Pacific Salmon Abundance Over the Past 300 Years. Science 290: 795-799.

Finney, B.P., Gregory-Eaves, I., Douglas, M.S.V. and Smol, J.P. (2002). Fisheries productivity in the northeastern Pacific Ocean over the past 2000 years. Nature 416: 729-733.

Mantua, N.J., S.R. Hare, Y. Zhang, J.M. Wallace,and R.C. Francis (1997). A Pacific interdecadal oscillation with impacts on salmon production. Bulletin of the American Meteorological Society 78: 1069-1079.