Climate change impacts on mesophotic regions of the Great Barrier Reef

• 成果类型: Article
• 署名作者: McWhorter, Jennifer K.; Halloran, Paul R.; Roff, George; Mumby, Peter J.
• 署名单位: University of Exeter; University of Queensland; National Oceanic Atmospheric Admin (NOAA) - USA; Atlantic Oceanographic & Meteorological Laboratory (AOML); Commonwealth Scientific & Industrial Research Organisation (CSIRO)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-10036
• DOI: 10.1073/pnas.2303336121
• 发表日期: 2024-04-16
• 关键词: coral ecosystems; pacific; refugia; water; mortality; distinct; stress; depth; heat

摘要

Climate change projections for coral reefs are founded exclusively on sea surface temperatures (SST). While SST projections are relevant for the shallowest reefs, neglecting ocean stratification overlooks the striking differences in temperature experienced by deeper reefs for all or part of the year. Density stratification creates a buoyancy barrier partitioning the upper and lower parts of the water column. Here, we mechanistically downscale climate models and quantify patterns of thermal stratification above mesophotic corals (depth 30 to 50 m) of the Great Barrier Reef (GBR). Stratification insulates many offshore regions of the GBR from heatwaves at the surface. However, this protection is lost once global average temperatures exceed -3 degrees C above preindustrial, after which mesophotic temperatures surpass a recognized threshold of 30 degrees C for coral mortality. Bottom temperatures on the GBR (30 to 50 m) from 2050 to 2060 are estimated to increase by -0.5 to 1 degrees C under lower climate emissions (SSP1-1.9) and -1.2 to 1.7 degrees C under higher climate emissions (SSP5-8.5). In short, mesophotic coral reefs are also threatened by climate change and research might prioritize the sensitivity of such corals to stress.