Crumbling Coral: Cold-Water Reefs in the Acidic Northeast Pacific and Their Implications for Other Regions of the USA

Cold-water reefs are fragile, complex ecosystems that extend into the bathyal depths of the ocean, creating three dimensional structure and habitat for a diversity of deep-water invertebrates and fishes, including commercially fished species.  The most prolific cold-water reef-building coral is Lophelia pertusa, which occurs at depths where aragonite saturation is three to four times lower than their shallow-water reef counterparts.  The current study employed ROV surveys (n=564, 2003-2014) to document the distribution of a widespread reef-building coral on the U.S. West Coast for the first time, providing empirical evidence of species survival but loss of reef integrity in the naturally acidified conditions.  The study found that while Lophelia can persist in the corrosive waters, its skeleton is smaller, thinner and more porous than Lophelia in regions such as the North Atlantic and US South Atlantic Bight, where the coral forms more expansive reefs of robust skeleton. Preliminary findings in the South Atlantic Bight suggest corrosive water will also be impinging on Lophelia reefs in this region.  The future health of these SAB reefs may depend on both the degree and rate of change, necessitating new monitoring efforts to evaluate carbonate chemistry with respect to cold-water reefs in the Southeast region.