Antarctic deep-sea coral larvae may be resistant to end-century ocean warming

The Western Antarctic Peninsula is home to a diverse assemblage of deep-sea species and is warming faster than any other region in the Southern Hemisphere. This study investigated how larval development of the Antarctic cold-water coral Flabellum impensum was affected by temperatures consistent with ocean warming trends predicted for the twenty-first century. F. impensum larvae were cultured under four temperature conditions and scanning electron microscopy, transmission electron microscopy, and flow cytometry were used to compare settlement, mortality, larval size, development, deformity, and cellular health over the course of 44 days. While temperature did not impact settlement, mortality, or larval stress, the warmer treatments did have a significant impact on developmental rate. Samples exposed to warmer conditions developed faster than those in cooler conditions. Increased developmental rates were not accompanied by increased stress indicators such as deformity, mortality, or programmed cell death, suggesting that larval health was not negatively impacted by the rate change and may indicate that F. impensum larvae are tolerant of warming temperatures. Development and deformity assessments considered larval condition during the period between release and settlement, when larvae are thought to be especially sensitive to environmental impacts, and when the effects of those impacts on settlement or mortality may be particularly consequential for biogeography and population survival. These results suggest that larval development of F. impensum may be largely resistant to ocean warming trends predicted for the twenty-first century.