P2.70 Thursday, Jan. 5 How Will Ocean Acidification Affect Reproduction? A Study of Sperm Respiration In The Purple Sea Urchin, Arbacia Punctulata. WATSON, B. L.*; PODOLSKY, R. D.; College of Charleston; College of Charleston firstname.lastname@example.org
As atmospheric CO2 levels continue to rise, the increase in CO2 concentration in ocean surface waters is leading to historically rapid declines in pH, a process called Ocean Acidification. Studies of the effects of ocean acidification have focused mainly on animals that rely on calcification, which is compromised by declines in pH, to produce skeletons or protective structures. Less studied are other biological processes that are also pH sensitive, such as the activity of spawned sperm that are normally held in a suppressed metabolic state at low pH in the gonad. We studied the effects of CO2-induced pH decline on reproduction in the sea urchin Arbacia punctulata by monitoring respiration rates of sperm incubated in sea water with CO2 concentrations predicted several hundred years into the future. Our results show a negative effect of pH on sperm respiration that is most dramatic in the next 100 years. In addition, we found a previously described negative relationship between sperm concentration and respiration, known as the Respiratory Dilution Effect (RDE). We are combining these measurements with studies of changes in sperm motility and fertilization rate to understand processes responsible for changes in fertilization success. It is not yet clear, for example, whether declines in respiration and activity may be offset by increases in sperm longevity as a consequence of the RDE.