Interactive effects of temperature and salinity on early life stages of the sea urchin Heliocidaris crassispina

摘要: Marine organisms are currently challenged by multiple and interactive environmental stressors. In the subtropics, warming intensified precipitation, hence, reduced salinity, particularly relevant. Using sea urchin, Heliocidaris crassispina, we investigated effects of low salinity on fertilization success early development. These planktonic developmental stages play significant roles in shaping population dynamics. Gametes were exposed to a temperature gradient (28–43 °C) while being held at two salinities (24 32). Fertilization had higher critical (LT50), which 50% individuals reached designated stage, 39 °C than that blastula formation 31 °C for both salinities, suggesting between-stage variations sensitivity. The LT50 was very close present-day recorded maximum surface small thermal safety factor. Larvae also reared eight-arm stage one four combinations temperatures 28 °C) 32), correspond observed during urchin’s spawning season. Low high reducing larval survivorship. However, amongst larvae survived combined stress, negative impact arm growth. Unexpected release blastula-like particles documented all treatments except control (24 °C Incomplete separations resulted conjoined twins, however, only found 28 °C. There significantly different responses growth between maternal lineages. Such intra-specific highlight presence phenotypic plasticity could imply genetic response stress. suggests although purple urchins experiencing extreme conditions stressful present, they may be able cope with future ocean conditions.