The physiological response of larval marine snails to environmental stressors.

摘要

Embryonic and larval stages are thought to be more sensitive to environmental fluctuations than later life history stages. Therefore, examining how marine larval gastropods might be affected by climate change stressors, in this case, high temperatures and ocean acidification (OA), becomes important for predicting long-term outcomes such as recruitment success and population structure.;This study first examined the effects of temperature on larval survival of the intertidal dogwhelk, Nucella ostrina, over a large geographic scale. Laboratory trials concluded that veliger survival decreased abruptly within a few degrees celsius for all sites. In addition, there was a significant relationship between veliger thermal tolerance and latitude, but habitat temperature and veliger thermal tolerance were not correlated. Data further yielded that some larval populations may be living near their upper thermal limit, and as sea surface temperatures continue to rise with climate change, a couple of degrees could impact the population structure of these encapsulated developers.;A growing body of research on calcifying marine invertebrates suggests that OA can have deleterious effects on development and various physiological processes in these organisms, especially since climate change models predict oceanic pH could decrease by additional 0.2-0.3 units (from pH 8.1 to an average of 7.9-7.8) by the year 2100. In laboratory experiments designed to mimic seawater chemistry in future oceans, we examined the effects of elevated CO 2 on larvae of two marine snails, Nucella ostrina and Haliotis rufescens. Larvae were raised in culture under control and experimental CO2 levels that span the range of current atmospheric CO2 concentrations (385 ppm) to a "worst case" scenario (∼990 ppm) predicted for the year 2100. Following development under conditions of ocean acidification, we measured larval thermal tolerance, shell integrity and shell formation. Our results showed elevated CO2 had a subtle influence on veliger thermal tolerance for both species. In addition, shell strength in Nucella ostrina veligers and gene expression patterns for genes involved in shell formation in abalone larvae were not changed. These results suggest that larval forms of these species may have the capacity to withstand environmental change.