Fassbender, A.J., C.L. Sabine, N. Lawrence-Slavas, E.H. De Carlo, C. Meinig, and S. Maenner Jones (2015): Robust sensor for extended autonomous measurements of surface ocean dissolved inorganic carbon. Environ. Sci. Tech., doi: 10.1021/es5047183.
The ocean plays an important role in global climate through the transport and storage of carbon, yet it is unclear how ocean warming and acidification will influence ocean carbon cycling on societally relevant timescales. This uncertainty is largely due to the challenges in developing autonomous marine sensors with the accuracy and endurance needed for long-term observational efforts that can resolve environmental variability. In addition, two carbonate system parameters must be measured simultaneously in order to fully constrain seawater carbonate chemistry and to quantitatively assess the physical and biogeochemical drivers of carbon transformations in the ocean. In an effort to expand the tools available to the scientific community for this research, we have developed a dissolved inorganic carbon (DIC) sensor designed for extended duration (~1 year) deployments on moored platforms. In this paper we describe the DIC sensor prototype and present results from two field deployments. This new sensor improves the accuracy of autonomous DIC monitoring on moorings by ~90%, and, when coupled with an autonomous carbon dioxide (CO2) or pH sensor, makes it possible to acquire the environmental data needed for climate quality, in situ carbon cycle studies.