Intertidal sand dollar Dendraster excentricus larvae are resilient to high temperatures in early development and at settlement

Abstract

Understanding how different stages in the life cycles of benthic marine invertebrates respond to environmental stressors is essential for predicting future population dynamics and can be critical to the management and conservation of species. With the rise of global warming and its effects on the ocean, this study examined the effects of temperature and chemical cues on early larval development and settlement success in the sand dollar Dendraster excentricus. Adults collected from an intertidal population on Orcas Island, WA. Individuals were spawned, and embryos and larvae were cultured under controlled laboratory conditions across a range of temperatures representative of typical intertidal field conditions. Data on early development and settlement under temperature and chemical cues were recorded. Results showed that elevated temperatures for 24 hours starting at fertilization accelerated developmental rates and produced abnormalities starting at 25°C. In contrast, temperatures as high as 30°C had no detectable effect on larval settlement but were lethal at 35°C. Additionally, the presence of sand as a cue for settlement had a significant effect on settlement decisions. These findings highlight D. excentricus as a model for thermal resilience and underscore the importance of thermal variability and extremes and the different sensitivities found at different stages in the life cycles of benthic marine invertebrates. More broadly, this work provides insight into how rising ocean temperatures may influence recruitment dynamics in benthic communities.