Reef and wild fishery conservation through exploiting satellite remote sensing of the marine carbonate system

Anthropogenic emissions of carbon dioxide (CO₂) levelled out in 2016, but have since begun to increase again. This continued increase in anthropogenic emissions means that it is now critical to monitor ocean carbon uptake. This long-term uptake of carbon dioxide (CO₂) by the oceans is reducing the ocean pH, a process commonly known as ocean acidification. The uptake is also altering the ocean chemistry and ecology, impacting marine ecosystems on which we rely. Recent efforts have highlighted the use of satellite Earth observation, exploiting empirical methods and salinity and sea surface temperature data, to monitor surface-ocean carbonate chemistry. These techniques complement in situ approaches by enabling synoptic-scale observation-based assessments of the global oceans and are particularly well suited to monitoring large episodic events. The nine year time series (May 2010-present) of observations of ocean salinity from space now provide the potential for time series analyses.

We will first demonstrate that observations from space can be used to estimate surface total alkalinity and total dissolved inorganic carbon with performance comparable to that of in situ driven empirical approaches. For alkalinty, the global combined uncertainties for these observations are ±17 μmol kg^-1 . We will then present early results from the European Space Agency Satellite Oceanographic Datasets for Acidification (OceanSODA) project demonstrating how large spatial-scale upwelling (of low pH waters), river outflows and compound events, and their subsequent impact on the surface water carbonate system, can be observed from space. Collectively this work exploits the synergistic use of remote sensing observations, in situ based climatologies, in situ and model re-analysis datasets, empirical statistical analyses and machine learning approaches.

These advancements are intended for supporting coral reef conservation, the designation of marine protected areas and investigating the health of wild fisheries, and early results of these applications will also be presented. These routes for exploitation are being co-developed with the U.S. National Oceanic and Atmospheric Administration (NOAA) and the World Wide Fund for nature (WWF).