June 1, 2017

F. Chan, J. A. Barth, C. A. Blanchette , R. H. Byrne, F. Chavez, O. Cheriton, R. A. Feely, G. Friederich, B. Gaylord, T. Gouhier10, S. Hacker, T. Hill, G. Hofmann, M. A. McManus, B. A. Menge, K. J. Nielsen, A. Russell 11, E. Sanford, J. Sevadjian & L. Washburn

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 earlyimpact
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.

Persistent spatial structuring of coastal ocean acidification in the California Current System (PDF)