Essential Ocean Variables for Biogeochemical Observations
Ocean biogeochemical (BGC) processes are fundamental for several key ocean ecosystem functions and services. For example, carbon dioxide uptake and storage by chemical uptake and biological fixation in combination with transport to depth remove anthropogenic carbon from the atmosphere and counteract global warming. Another important example would be nutrient regeneration from organic matter remineralization that sustains ocean productivity and, hence, also seafood supply. Although many BGC processes are rooted in surface waters where primary productivity and ocean / atmosphere exchange takes place, the deep ocean contributes strongly to the cycling and sequestration of elements. Without a consideration of organic particle attenuation in the deep pelagic and rates of remineralization and accumulation at the vast deep seafloor, the efficiency of the biological carbon pump and the recycling of nutrients – and potential effects of global change – can hardly be quantified. Considering the relevance of the deep ocean, the Deep Ocean Observing Strategy ‘DOOS’ is revising the Essential Ocean Variables (EOVs) specified by the Global Ocean Observing System (GOOS) with a deep ocean perspective. The DOOS community recognized, that most GOOS BGC EOVs are also relevant for deep ocean observations. However, the bottom of the sea requires more attention to assess its contribution to ocean BGC. ‘Seafloor labile organic matter’ and ‘seafloor respiration’ are candidates for additional EOVs beyond the GOOS EOVs ‘oxygen’ and ‘particulate matter’. Online questionnaires are prepared to facilitate an expert revision of GOOS BGC EOVs in order to make specific suggestions for modifications to the responsible GOOS panel. The revision includes the target phenomena and spatiotemporal scales, the observing platforms and networks considered relevant, and the requirements of observations. This contribution introduces the revision approach and invites experts to take part.