The California Current Ecosystem (CCE) LTER site: Mechanisms underlying ecosystem transitions

The CCE-LTER site is a coastal upwelling biome forced by physical processes on a variety of time and space scales.

We have been able characterize these multiple scales of forcing thanks to a partnership with CalCOFI, now in its 64^th year of ocean observations, permitting us to recognize interannual, decadal, and inter-decadal scale changes.  From such observations we have identified relatively abrupt ecosystem transitions in key ecosystem properties; the mechanisms underlying these transitions are a central focus of the CCE site.  Recent evidence from 3 decades of satellite time series suggest that previously understudied ocean features - submesoscale and mesoscale fronts - show a temporal trend of increasing spatial coverage in our region.  Six years of ocean glider observations  show reproducible gradients of phytoplankton and zooplankton biomass in association with such frontal features and suggest they are a key element of the ecological disturbance regime in our region.  Accordingly, we are focusing our experimental process cruises on the importance of spatial discontinuities associated with submesoscale fronts and eddies, whose changes over time may play a disproportionately large role in the flux of nutrients, growth and grazing rates, and predator-prey interactions, thereby affecting ecosystem transitions.  Our LTER site is structured around 6 program elements: Experimental Process Cruises, Time-series Observations, Modeling, Information Management, Education-Outreach-Capacity Building (EOCB), and an Integrated Science for Society and the Environment (ISSE) program.