Inconsistencies in Ocean Temperature Monitoring for Coral Reef Applications

Abstract

      Coral reefs are extremely vulnerable to climate-driven warming of the ocean, which threatenstheir survival. Coral responses to rising temperatures are currently studied and predictedusing sea surface temperature (SST) from multiple sources. Despite the importance ofharmonizing complementary data from different sources, there is no clear understanding ofthe consistency or lack of it among the main datasets used and the predictions made usingthem. Understanding the consistency among the different SST data applied to coral reefsmay facilitate monitoring and understanding global warming's impact on coral reefs. Fourtypes of SST data across North-Western and South-Western Australia are compared toassess their differences and ability to predict historical coral bleaching events. Four decadesof coral bleaching indicators, Degree Heating Week (DHW) and Degree Heating Month (DHM)were calculated based on satellite-derived SST, global climate models (GCM), and coral corederived proxies. Both DHW and DHM were inconsistent among datasets and did notaccurately predict moderate and severe bleaching events. Despite high DHWs and DHMs,some reefs did not experience bleaching, suggesting site-specific coral adaptation. SST datafrom different sources had better consistency for frequency and were consistent with coralcore derived proxies of SST, highlighting the importance of coral cores in understanding pastthermal stress. By exploring the differences and similarities among data sources, this studyhighlights the need to compare thermal stress indicators from different datasets for a betterunderstanding and a more robust prediction of coral response to thermal stress.