Arguments have been made for the global coastal ocean being either a source or a sink of CO2 with the atmosphere to the tune of ~1 petagram C per year. The uncertainty is the result of strong coastal ocean variability at a range of temporal and spatial scales, and a lack of adequate data coverage in both time and space to constrain this variability. For instance, in the northeast Pacific, recent data compilations show that high latitude regions possibly constitute a strong sink for atmospheric CO2, while mid-latitude regions are close to neutral and low latitude regions may produce a large source. To improve the accuracy of the CO2 exchange estimates requires the collection of new data in targeted regions of poor data coverage where fluxes are potentially important, coupled with observations of physical and bio-optical parameters to facilitate data interpretation and the development of data proxies for surface ocean CO2 concentration.
In this research, PIs from Oregon State University will focus on the North American Pacific coast from Oregon to Alaska potentially a strong sink region, but one with extremely poor data density. Hosted on vessels and moorings of opportunity, they will conduct cruises in this targeted region of few observations with a view to capturing the seasonal cycle of air-sea CO2 flux. The spatial and temporal patterns in the CO2 data will be interpreted in the context of in situ and satellite physical and bio-optical data. The new data will be used to recalculate the total North American, west coast, air-sea CO2 flux, and be incorporated into an existing database for satellite algorithm development. Accurate estimates and a better understanding of northeast Pacific coastal fluxes are also important because these waters pre-condition the CO2 chemistry of air masses flowing onto the continent, thus impacting estimates of terrestrial carbon cycling.
In terms of broader impacts, this research addresses an important question relevant to carbon cycling in the coastal ocean. The project will train a PhD student in a strongly interdisciplinary environment. Undergraduates will be involved in the project as REU students, at least partly advised by the graduate student, providing an important mentoring opportunity at this stage of his scientific career. High school students will be hosted through the Apprenticeships in Science and Engineering program, which includes a Summer Conference of seminars on career opportunities.
