Acclimatisation and adaptive capacity of sea urchins in a changing ocean: Effects of ocean warming and acidification on early development and the potential to persist

Abstract

Anthropogenic emissions of carbon dioxide are causing the oceans to simultaneously increase in temperature and acidification. As the life cycle of many marine invertebrates involves broadcast spawning, understanding the sensitivity of gametes, fertilisation and developmental stages is essential to determining species vulnerability to ocean change stressors. This thesis uses free spawning echinoids as model species to address this issue with an aim to identify effects of ocean acidification on the extracellular jelly coat of the egg with a focus on four sea urchin species; Centrostephanus rodgersii, Heliocidaris erythrogramma, Heliocidaris tuberculata, Echinometra mathaei. As sea urchins provide a tractable system for study of gamete and fertilisation responses to stressors, as well as investigation of genetic variation, the genetic basis of resistance to climate change stressors is also investigated in polar, tropical and temperate sea urchins: Sterechinus neumayeri, Pseudoboletia indiana and Heliocidaris erythrogramma. Data from the experiments across the all species show inherent differences in the response of gametes to ocean stressors, as well as differences in gamete compatibility which can drive differing responses to ocean change. Across polar, tropical and temperate sea urchins, the mechanisms that may facilitate persistence in a changing ocean differ, revealing the potential winners and losers.