Millennial scale climate variability of the northeast Pacific Ocean and northwest North America based on radiolaria and pollen

Radiolaria and pollen abundances in marine sediment cores from the northeas t Pacific are used to reconstruct oceanographic and continental climate cha nge during the past glacial cycle (0 150 kyr). These data allow direct comp arison of the climate response of continental and oceanic systems. Detailed delta O-18 and AMS-C-14 measurements provide a link into global stratigrap hic frameworks. Canonical correlation analysis extracts two modes of variat ion common to both the Radiolaria and pollen records. The first mode of var iation correlates an assemblage of Radiolaria associated with coastal upwel ling with increased redwood, western hemlock, and alder pollen. This associ ation is consistent with the modern relationship between coastal upwelling, coastal fog and redwood forests. A second canonical mode relates an oceani c fauna now found in highest abundance in the far North Pacific with reduce d pine and western hemlock pollen abundance. Comparison of these records to an ice core delta O-18 record suggests that at wavelengths > 3000 years, warm events in Greenland are correlated to int ervals of increased coastal upwelling off Oregon, decreases in importance o f very cold North Pacific fauna (suggesting warming), and increases in poll en associated with wetter coastal environments. Radiolarian based sea-surfa ce temperature estimates suggest that the variability of the northeast Paci fic on this time scale is about 2 degreesC. Warming in the coastal regions reflects reduced advection of the California Current, but is moderated by i ncreases in cool coastal upwelling. We infer that the response of the north east Pacific to millennial scale climate changes is related to changes in a tmospheric circulation at mid- to high latitudes. Preliminary analysis suggests that oceanic variability off Oregon at wavele ngths < 3000 years is similar to the Dansgaard-Oeschger cycles of the ice c ore delta O-18 records. This variability is associated with changes in subt ropical faunal elements without similar changes in other faunal elements. T his finding suggests that, unlike longer-period millennial scale events, th e propagation of the shorter wavelength events to the Northeast Pacific is through subtropical or tropical teleconnections. :,(C), 2001 Elsevier Scien ce Ltd. All rights reserved.