UC San Diego

The California Current System (CCS) is one of the most productive regions in the whole world, and as such, one of the most studied as well. Observational records throughout the years have shown scientists that CCS is under the influence of major climate events such as El Niño Southern Oscillation (ENSO). Yet there are still many questions regarding the exact mechanisms trough which ENSO teleconnections imprint variability in the physical conditions of the CCS, and how this further impacts the California Current Ecosystem (CCE).

The focus of this dissertation is to shed light over the regional expressions of ENSO over the CCS, and how physical-biogeochemical interactions drive a coherent response associated with El Niño and La Niña events. The first part describes the response of the CCS to ENSO as captured by one coarse resolution model and one eddy-resolving high-resolution model. The findings help to better understand the mechanistic response of the CCS to ENSO and build on the existing framework for ecosystem predictability. A key result from the first part is that the cooling of the CCS associated with La Niña is more consistent than the warming associated with El Niño. Also, with the high-resolution model we are able to show the bottom-up response of the CCE, and the diversity in the response among different trophic groups.

The last part focuses on proposing new avenues for future research to untangle the intricate components of the CCE response that are associated with mesoscale activity, and how they are affected by ENSO variability.