Sack Lunch Seminar (SLS)

The ocean is a major sink of anthropogenic CO2 emissions. In order to predict future atmospheric CO2 levels and global climate, we must improve quantification of the ocean carbon pumps, which sequester CO2 from the atmosphere on timescales from years to millennia. In this talk, I will present field data from a quasi-Lagrangian cruise in Monterey Bay, CA and use it to demonstrate how in situ measurements of dissolved gases can be used to quantify the biological and solubility pumps. In particular, O2 concentration and isotopic composition are tracers of gross and net productivity. A persistent challenge in quantifying biological productivity from O2 measurements is the need to accurately parameterize the physical processes that also alter O2 concentration and isotopic composition (e.g., bubble-mediated gas exchange, diffusive gas exchange, and mixing). Measurements of multiple inert gases, such as the noble gases, are used to develop parameterizations for these physical processes. These parameterizations are then applied to bioactive gases such as O2 and CO2, thereby improving estimates of the ocean carbon pumps. Additionally, I will compare in situ gas tracer methods for quantifying productivity with simultaneous incubation- and sediment trap-based productivity estimates.