Meeting Abstract
A paradigm of Antarctic biology is that Southern Ocean ectotherms are highly stenothermal, owing to millions of years of evolution under cold and thermally stable conditions. Given the predicted rapidity of climate change, it has become important to understand the response of polar ectotherms to rising temperatures. However, compared to adult stages, relatively little is known about the ecology of Antarctic invertebrate embryos and larvae or their sensitivity to temperature. For some Southern Ocean invertebrates, small increases in temperature have been shown to dramatically increase metabolic and developmental rates. Our study investigates the effect of rising temperatures on the development and metabolic performance of larvae from a range of Antarctic invertebrate taxa, including nudibranchs, echinoderms, and pycnogonids. Animals will be collected by SCUBA divers, and embryos and larvae will be assessed for thermal sensitivity using several indices of physiological performance. We will expose embryos and larvae to temperatures ranging from ambient to their experimentally determined critical temperatures and measure the effects of temperature on (1) heart rate, (2) oxygen consumption (as a proxy for metabolic rate), and (3) lethal temperature (as LT50). This will provide insight into the upper thermal limits of early stages of a diversity of Antarctic taxa, and potentially shed light on the mechanisms underlying failure at high temperatures. This research will be conducted starting in September 2019, at McMurdo Station, Antarctica. The goal of this study is to provide insight into the vulnerability – or resilience – of Antarctic ectotherms to rising ocean temperatures. Funded by NSF-OPP-1745130 to ALM.
