86 / 2023-07-28 21:20:08

Impacts of marine heatwaves on coral reef in the Qilianyu Islets

marine heartwaves,coral reef,Landsat-8/9,Xisha Islands

Marine heatwaves (MHWs) are prolonged extreme events of anomalously warm ocean conditions that may drive shifts in species distributions and alter the structure of coral reef ecosystems. In the scenario of global warming, how coral reefs correspond to MHWs in the Xisha Islands remains unclear and deserves thorough investigation. In this study, satellite-derived sea surface temperature was used to investigate MHWs around Xisha Islands. The effects of MHWs on coral reef was analyzed based on Landsat-8/9 observations during 2014-2022. From 1982 to 2022, MHW frequency, days and duration in the Xisha Islands exhibited significant increasing trends at a rate of 0.92 times/decade, 19.18 days/decade, 7.67 days/time/decade, respectively. Negative correlations was found between coral substrate ratio and MHW days and cumulative intensity. The sand substrate ratio showed a significant positive correlation with the MHW duration with an R of 0.79. The seagrass substrate ratio demonstrated positive correlations with the MHW days and frequency while negative correlations with the MHW duration and maximum intensity. Our findings can provide insights into the impact of extreme events on coral reef ecosystems.