Summary
This study presents the first examination of the effect of both temperature and salinity on fertilisation and development in an Antarctic echinoderm. Previous studies on Antarctic species have not investigated the combined effects of temperature and salinity, focusing on only single factor studies, rather than on the interactions of multiple stressors. In this study, temperature and salinity were manipulated concurrently in cultures with the common Antarctic sea urchin Sterechinus neumayeri to provide greater insights regarding organism responses to climate change. Ambient temperature (-1°C) was compared against two temperature treatments simulating predicted near-future warming (1°C) and and extreme scenario (3°C), while ambient salinity (35ppt) was tested against a moderately reduced (30ppt) and extreme (25ppt) salinities. Temperature and salinity were found to interact, with reduced fertilisation success attributed to both increased temperatures and reduced salinities. Development success was strongly affected by salinity, while development rates were most strongly influenced by temperature. Changes in the environment resulting from global warming are likely to impact marine communities in polar areas. This study provides evidence that near-future climate change scenarios are likely to negatively affect fertilisation success and embryonic development of Sterechinus neumayeri, used here as a model for other broadcast spawning Antarctic invertebrates.