Meeting Abstract
A paradigm of Antarctic biology is that marine ectotherms exhibit slow growth, low metabolic rates, and extended development, and that these processes are highly sensitive to temperature. We measured the effects of temperature on metabolism and development across the life cycle of Ammothea glacialis, an Antarctic sea spider (Pycnogonida). Egg masses, larvae, juveniles, and adults all showed large increases in metabolic oxygen consumption between -1.8°C (ambient) and +4°C. We estimated Q10, an indicator of thermal sensitivity of rate processes, for metabolism at each stage. Q10s were generally higher than the expected biological range of 2-3; stage-specific averages varied between ~4 and >20. Adults and juveniles had higher Q10s than larvae or eggs. Despite the > 4 orders of magnitude in size between our juveniles and adults, we saw no evidence for a change in thermal sensitivity with body size within these two groups. Over the same temperature range, the Q10 for larval developmental rate was close to that of larval metabolism, suggesting the thermal sensitivity of these two processes are coupled. For juveniles and adults (but not larvae or egg masses) we also measured metabolic rates over a smaller range of temperature, between -1.8 and +1°C. Here the effects of temperature were even more striking, with average Q10s >50. These results suggest that small changes in temperature could have substantial effects on the timing of life history events, the quality and quantity of offspring, population growth rates, and potentially ecosystem function in the Antarctic benthos. NSF PLR-1341476
