Meeting Abstract
Ectothermic marine organisms are especially sensitive to decreased oceanic pH caused by increased atmospheric pCO2 and increased frequency and severity of extreme heat events. Qualitative and quantitative effects of lowered pH and acute thermal stress on embryonic heart rate of the species Porcellana platycheles was investigated. Embryos taken from field-collected females (n = 6; 96 embryos/female) were reared until hatching (~27 days) under one of two pH treatment conditions (pH=8.0, pH=7.6). Embryos were exposed to one of four temperature treatments: constant ambient 20 °C, one hour exposure to 31 °C on Day 1, one hour exposure to 31 °C at start of heart beat, or both one hour exposure to 31 °C on Day 1 and start of heart beat. Videos of the embryos were filmed, and their average heart rate was determined by counting the heartbeats. The embryos were classified as having an arhythmic, unevenly spaced, or normal heart rate. Those embryos exposed to 31 °C for one hour on Day 1 and to both 31°C on Day 1 and at the start of heart beat had the greatest variance in heart physiology, suggesting that P. platycheles are likely to be negatively affected under predicted climate change scenarios.
