Award: OCE-1219537

Project Summary. Biosensors allow new approaches to understand biogeochemical processes in the oceans. We developed a highly effective and quick assay to measure the distribution of the model protein "RuBisCO" in the South Atlantic Ocean. Intellectual merit. Dissolved organic matter (DOM) is the largest reservoir of carbon in the oceans, and it is of similar magnitude to the atmospheric CO2. The role this carbon pool plays globally has important consequences for the carbon cycle, climate and global sustained marine life. In this study we attempted to understand the distribution of biomarker proteins present in the oceanÆs DOM to develop insights into the export of carbon to the deep ocean as well as its accumulation and transport of modern organic carbon in the deep ocean. Proteins provide a rich source of biological information and the identification of proteins in DOM enables us to understand the complex sources and dynamics of carbon containing material in the ocean. Furthermore, proteins are a direct link between their biological and phylogenetic presence and biogeochemical dynamics. The distributions of relevant proteins to important processes (for example, RuBisCO to carbon fixation, nitrogenase to nitrogen fixation) can be used to reveal information that has been hidden until now. Our findings suggest that the identification and quantification of biomarker proteins provide a powerful approach to understanding biogeochemical pathways. Broader Impacts We have merged the sciences of proteomics with biogeochemistry and oceanography. This study used immunosensors coupled with proteomics to provide information on the cycling of a model protein "RuBisCO" as a biopolymer in the DOM pool in the South Atlantic Ocean. We demonstrate that protein biomarkers allow in situ tracking of marine proteins, their biosynthesis, transformation, and degradation in un-concentrated seawater. Understanding the formation, degradation, and preservation of proteins in the DOM pool allows scientists to elucidate their role in the global carbon and nitrogen cycles that have important consequences in ocean and global ecosystems. Last Modified: 05/29/2015 Submitted by: Monica Orellana