Future climate change threatens to affect global circulation patterns and upwelling along coastal margins. These regions support the the majority of marine biological production and the world’s largest fisheries. The purpose of the Up.R.I.S.E.E. study is to characterize the biological response to upwelling in the Southern California Bight using a suite of geochemical measurements, which may help us to better understand how future climate forcing may affect the biological pump and nutrient cycling in these regions. We sampled at SPOT every two weeks between the winter and summer months in 2013 and 2014, during two periods of increasing upwelling velocity, to see how nutrient transport and production change over time. To estimate the rate of upwelling and eddy diffusive nutrient transport, we use a mass balance of the cosmogenic radionuclide, 7Be, in the surface ocean. Biological production and particle export estimates are made using the concentration and isotopic composition of dissolved oxygen, a 234Th budget and surface-tethered sediment traps. These parameters give us a well-rounded view of how the ecosystem in San Pedro Basin utilizes deep water nutrients delivered to the surface ocean through upwelling and the efficiency at which it can export, rather than recycle, these nutrients within the system, which is also a measure of the ability of the ecosystem to serve a sink for CO2 in the atmosphere. We have also teamed up with the Burt Jones’ ocean optics laboratory to deploy an autonomous glider between San Pedro and Catalina Island equipped with optical sensors to tell us what the biological community is doing at SPOT between sampling cruises and give us an idea of the spatial variability in this dynamic coastal region over the course of the study.
For more information on the project, please click here.