Transgenerational effects of temperature stress: Impacts on and beyond coral reproduction

Guy Harvey Oceanographic Center Facility

As oceans warm, corals are exposed to temperatures outside their normal range, causing stress to the organism. Previous studies demonstrate that temperature stress negatively impacts the reproductive output of corals. However, the transgenerational impacts of temperature stress on corals are unknown. Additionally, corals are expected to experience warmer temperatures months before the spawning season, when their gametes are still developing. To assess transgenerational effects of temperature stress during gametogenesis, colonies of Montastraea cavernosa were exposed to elevated temperature for two weeks four months prior to spawning, and then returned to the reef. At spawning, gametes from temperature stressed and unstressed corals were combined to create four fertilization crosses: unstressed eggs and sperm, unstressed eggs with stressed sperm, stressed eggs with unstressed sperm, and stressed eggs and sperm. Larvae and juveniles from each cross were kept at ambient (29°C) and elevated (31°C) temperatures. Larvae and juveniles originating from stressed gametes had lower survival. When temperature stress occurred during both gametogenesis and larval or juvenile development, the decrease in larval and juvenile survival was exacerbated. These results demonstrate that temperature stress during gametogenesis has latent effects on larval and juvenile survival.