Sea-surface temperature anomalies associated with the 1997-1998 El Nino recorded in the oxygen composition of planktonic foraminifera

Anomalously warm sea-surface temperatures and associated high rainfall propagated northward from the eastern equatorial Pacific along the western margin of North America during the 1997-98 El Nino. We present data from the Guaymas Basin (Gulf of California) and the Santa Barbara Basin (Southern California Borderlands) that clearly demonstrate that the oxygen isotope composition of planktonic foraminifera accurately records the local sea-surface temperature changes related to the El Nino phenomenon. On the basis of this observation, the varved sediments accumulating in these basins should contain a detailed history of both the occurrence and intensity of past El Nino events.