Temporal patterns in innate immunity parameters in reef‐building corals and linkages with local climatic conditions

Abstract

Abstract Extremes in seasonal environmental conditions can significantly impact the health and physiological functioning of reef corals, underscoring the need for knowledge of seasonally specific baselines from which to monitor and forecast impending stress. Increases above summertime means in seawater temperature, sunlight intensity, turbidity, or sedimentation may reduce coral immunocompetency and increase disease and bleaching susceptibility. We analyzed temporal patterns in innate immunity parameters over nine time points throughout one year to establish baseline levels from which anomalies might be detected for representative species from three major reef‐building coral families (Acroporidae, Faviidae, and Poritidae). Temporal patterns in both phenoloxidase activity and expression of green fluorescent protein‐like proteins varied among the three families, as did overall constitutive levels. For example, Porites cylindrica had 2.8‐fold higher yearly average levels of phenoloxidase activity than Acropora millepora, which had the lowest levels. In contrast, mean fluorescence was lowest in Acropora millepora and highest in Echinopora mammiformis. Relationships between the potential physical drivers (seasonal variation in seawater temperature, rainfall, salinity) and temporal patterns in these parameters also differed among the three species. For example, phenoloxidase activity was positively correlated with seawater temperature in A. millepora, but negatively correlated in both E. mammiformis and P. cylindrica. Distinctions in constitutive levels and temporal patterns in these parameters among species suggest that corals from these three families have evolved different strategies for investing resources into innate immune parameters. Such differences highlight the need for species‐specific baselines and long‐term assessments to accurately predict coral reef trajectories in rapidly changing environments.

Keywords

• chromoprotein
• coral
• fluorescence
• green fluorescent protein‐like proteins
• immunity
• indicator