Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Effects of Temperature on Coral Larval Performance (#63)

Nataly Gutierrez Isaza 1 2 , Eugenia M Sampayo 1 2 , Steven J Dalton 2 3 , Carrie A Sims 1 2 4 , Catherine E Lovelock 2 , John M Pandolfi 1 2
  1. Australian Research Council Centre of Excellence for Coral Reef Studies, The University of Queensland, St Lucia, QLD, Australia
  2. School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia
  3. National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW, Australia
  4. Australian Institute of Marine Science, Townsville, QLD, Australia

Understanding biotic responses to temperature regimes assists in clarifying the potential for species to adapt to climate change. Ocean warming acts as a selective force on coral species, creating changes in community structure across tropical and subtropical reefs. Subtropical environments may act as refugia for corals escaping warming tropical waters. Migration of coral species into thermal refugia will, however, rely on the thermal performance of dispersive larvae. Given the importance of thermal regimes on coral larval stages as oceans warm, we tested larval survival and settlement (i.e., performance) following a range of pelagic larval durations (PLD) for four Acropora species at Heron Island (Australia) under three temperature conditions (22.5°C, 25.5°C, and 28.5°C). Larval survival decreased with increasing PLD for all species, but the mortality rate was strongly species-specific. Settlement varied among species, with species responding differently to variation in PLD and temperature. While temperature slightly influenced coral larval performance, the magnitude of the response was less than for PLD, suggesting that other life stages during the dispersive stage (e.g., embryogenesis, larval development) might be more susceptible to thermal stress than larvae that have reached competence and, therefore, play a larger role in the detrimental effects of ocean warming on corals.