Aquatic Sciences Meeting, Albuquerque 2001

SS41 Diversity in the Plankton: Patterns & Mechanisms at Different Scales (Spatial and Temporal Connections)

Date: Thursday, February 15, 2001, Time: 4:15:00 PM

Location: Dona Ana

Ohman, M, D, Scripps Inst. of Oceanography, La Jolla, USA, mohman@ucsd.edu

Lavaniegos, B, E, Scripps Inst. of Oceanography & CICESE (Ensenada,MX), La Jolla, USA, berlav@cicese.mx

TEMPORAL PATTERNS OF CALIFORNIA CURRENT PELAGIC DIVERSITY OVER THE PAST 50 YEARS

We have been analyzing temporal patterns of pelagic diversity of holoplanktonic invertebrates from the California Current System (CCS), as sampled by CalCOFI over the past five decades. This study is one component of the U.S. GLOBEC Northeast Pacific Program. Zooplankton assemblages are affected by pronounced physical climate signals on a decadal scale (such as the 1976-77 Regime Shift) as well as those on an interannual scale (especially strong El Ninos), but zooplankton taxa are differentially influenced by such events. Some effects of the 1976-77 regime shift, such as the local disappearance of four species of salps, a possible decrease in hyperiid amphipod diversity, and increased importance of one euphausiid species, have persisted for the ensuing 24 years. However, other members of the zooplankton appear to have been relatively unaffected by the same climate event. During strong El Nino events the percent similarity of samples of planktonic copepods declines, but these interannual effects appear to be reversible (G. Rebstock, unpubl.). We will discuss such perturbations to and persistence of pelagic diversity in this eastern boundary current ecosystem.

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Aquatic Sciences Meeting, Albuquerque 2001

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