Integrated Model of Ocean Acidification and Hypoxia to Support Ecosystem Prediction and Environmental Management in the California Current Ecosystem

Martha Sutula1, James C McWilliams2, Curtis A Deutsch3, Richard F Ambrose4, Simone R Alin5, Nina Bednarsek6, Daniele Bianchi2, Richard A Feely7, Faycal Kessouri1,2, Mark Gold4, Karen McLaughlin1, Liz Ohlsson3, Lionel Renault2 and Stephen Weisberg1, (1)SCCWRP, Costa Mesa, CA, United States, (2)University of California Los Angeles, Atmospheric and Oceanic Sciences, Los Angeles, CA, United States, (3)University of Washington Seattle Campus, School of Oceanography, Seattle, WA, United States, (4)University of California Los Angeles, Los Angeles, CA, United States, (5)NOAA, Seattle, WA, United States, (6)University of Washington, School of Marine and Environmental Affairs, Seattle, WA, United States, (7)NOAA Pacific Marine Environmental Laboratory, Seattle, WA, United States
Abstract:
The California Current System (CCS) is among the most biologically productive regions of the world ocean, but upwelling makes it vulnerable to ocean acidification and hypoxia (OAH), which have been observed in recent decades. Three phenomena have been implicated: 1) large scale changes associated with climate warming, 2) natural variability, and 3) anthropogenic nutrient and carbon inputs. The relative importance of these drivers has not been systematically evaluated, but needed to manage coastal resources at local scales. Disentangling these stresses on OAH requires an integrated systems modeling approach. This project, in its early stages, will investigate the following questions: (1) How do the cycles of carbon, oxygen and nutrient function in the CCS in the presence of large-scale anthropogenic CO2 inputs and climate changes? (2) How much do local inputs of nutrients and CO2 contribute to altered productivity and OAH? (3) How do rates of OAH from local inputs compare to those originating from basin-scale climate change and remote transport of anthropogenic CO2? (4) What are the physiological impacts of OAH on ecologically-important pteropods, and what are valid empirical and modeled-expressed relationships between pteropod responses and OAH state variables? (5) Which areas are susceptible to OAH and how will susceptibility change between now and 2060? To address these questions, an OAH model is under development, based on the Regional Oceanic Modeling System (ROMS), comprising circulation, biogeochemical cycles, and lower-trophic ecosystem of the CCS. Sensitivities of pteropods to OAH and temperature will be measured to incorporate into the model as new ecosystem parameters. Model simulations will be validated against observational data. The model will be used to understand the relative contributions of natural climate variability, anthropogenically-induced climate change, and anthropogenic nutrient and carbon inputs on the trends of OAH in the CCS.

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