Burke Hales, Ph.D
Oregon State UniversityOcean Interior Connections to Enhanced Near Shore Carbonate Corrosivity: Implications for North American Pacific Oyster Evolution?
Wednesday — May 12, 2010
Pacific Forum — 3:00 p.m.
Ocean acidification, the change in seawater chemistry as a result of invasion of anthropogenic CO2 into ocean waters, is expected to alter open ocean chemistry significantly with respect to calcium carbonate biominerals by the end of the century, but its effects are already exacerbating extreme conditions in naturally variable systems that experience coastal upwelling. In addition to direct inputs of CO2 are climatically-driven changes in ocean interior biogeochemical cycling that may be compounding corrosivity by intensifying addition of metabolic CO2. Recent results off the Oregon coast show close-coupling between the deep offshore shelf-break and nearshore water chemistry, and strong coherence between naturally-fluctuating ambient CO2 chemistry and oyster larval survival failure, with larval Crassostrea gigas failing to form pre-settlement shell material in waters undersaturated with respect to aragonite, but surviving well in waters strongly supersaturated with respect to the mineral. The C. gigas oyster that is the basis of the commercial oyster industry on the Pacific Coast of North America is native to the western Pacific, and has several distinct reproductive strategies from those of the Ostrea lurida oyster native to this eastern boundary upwelling system. The distinct biogeochemical differences between the eastern and western boundaries of the Pacific may have led to the evolution of different reproductive strategies by these two species.
Next: May 19-Nitin Baliga