Abstract
The near-term progression of ocean acidification (OA) is projected to bring about sharp changes in the chemistry of coastal upwelling ecosystems. The distribution of OA exposure across these early-impact systems, however, is highly uncertain and limits our understanding of whether and how spatial management actions can be deployed to ameliorate future impacts. Through a novel coastal OA observing network, we have uncovered a remarkably persistent spatial mosaic in the penetration of acidified waters into ecologically-important nearshore habitats across 1,000 km of the California Current Large Marine Ecosystem. In the most severe exposure hotspots, suboptimal conditions for calcifying organisms encompassed up to 56% of the summer season, and were accompanied by some of the lowest and most variable pH environments known for the surface ocean. Persistent refuge areas were also found, highlighting new opportunities for local adaptation to address the global challenge of OA in productive coastal systems.
Highlights
Eastern boundary current upwelling systems such as the California Current Large Marine Ecosystem (CCLME) represent one of the ocean’s most productive biomes, sustaining one-fifth of the world’s fisheries[1]
Our findings indicate that coastal organisms in the CCLME face some of the lowest, and some of the most dynamic pH environments currently known for surface marine systems (Fig. 2)
Expansion of paired shelf and nearshore observations will be important for further testing the strength of cross-shelf coupling in ocean acidification (OA) exposure
Summary
Eastern boundary current upwelling systems such as the California Current Large Marine Ecosystem (CCLME) represent one of the ocean’s most productive biomes, sustaining one-fifth of the world’s fisheries[1]. Broad-scale observations[2], and models[3] have highlighted the biogeochemical sensitivity of the CCLME to the rapid progression of ocean acidification (OA) This susceptibility reflects the central role of upwelling currents in connecting coastal waters with the dissolved inorganic carbon (DIC)-rich ocean interior, and the high potential for active carbon remineralization over productive continental shelves. For coastal systems most at risk from OA, this limitation impairs our understanding of how biological and socio-economic vulnerability[10] are distributed, and whether spatial management tools can be applied to ameliorate local impacts of globally-driven changes in ocean chemistry[11] To resolve this uncertainty, we implemented an ocean observing network consisting of custom-designed pH sensors deployed in rocky intertidal habitats (see supplementary materials for methods) to provide the first high-frequency, multi-year view of near-shore OA progression across 1,000 km of the CCLME
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
