Interannual Variability

### Interannual Variability in Biological Responses

How will climate change alter California Current ecosystems, through changes in the length, strength, frequency and timing of ENSO cycles and other interannual variations?

- What are the natural modes of variability and covariability between components of the ecosystems in the CCS on interannual and longer time scales and what is the relation between these modes, past climate variability and potential future climate change?

- Is the response to perturbed forcing during ENSO events more complex than simple expansions and contractions of range? Can these more complex changes serve as analogs for responses to longer climatic changes?

The latter question encompasses long time frames as well as short, and therefore relates to issues discussed below under "Interdecadal Variability" as well. The ENSO cycle and especially warm phase (El Nino) events may serve as useful proxies for examining ecosystem responses to longer-term, more gradual climate change because of their dramatic impacts on both the physical environment and biological populations of the CCS. A U.S. GLOBEC study of the CCS should be prepared to determine how ecosystem responses to warm ENSO events differ between regions of the CCS. Finally, given the relatively short-term physical impact of warm ENSO events (1-3 years), one might be able to address the following questions:

How does the generation time of marine animals influence the impact of warm events?

How does the recovery rate of populations perturbed by an ENSO event differ for benthic versus pelagic populations?

How would these populations be affected by changes in the frequency or intensity of warm ENSO events?