On April 15, the United States National Oceanic and Atmospheric Administration and the International Coral Reef Initiative announced that the world was experiencing it’s 4th Global Bleaching Event (GBE4). Since February 2023, mass coral bleaching has been documented across at least 70 different countries/territories spanning the northern and southern hemispheres of all ocean basins (as of 9 August 2024). GBE4 has been record-setting, as >74% of the world’s reef area has experienced bleaching-level heat stress since January 2023, exceeding the previous record set during the 3rd Global Bleaching Event that spanned 2014-2017 (GBE3, 65.7%).
In an effort to minimize concomitant impacts on heat-stressed corals, popular tourist areas have been closed at Pling Island in Phuket, Thailand, and the Maldives temporarily halted all coastal development projects. Coral reef areas in both the northern and southern Atlantic Ocean have experienced the most extreme levels of heat stress during this event, with Degree Heating Week (DHW, ºC-weeks) values 2-3 times greater than has ever occurred before in the satellite record.
The majority of reef areas in the wider Caribbean and south Atlantic exceeded 16 ºC-weeks, with some regions surpassing 20 ºC-weeks; these extreme levels of heat stress have driven coral mortality ranging from 60-99% of all corals during past events. Over the past 365 days, 99.9% of all reef area in the Atlantic Ocean have experienced bleaching level-heat stress. Record-setting heat stress has also occurred in the eastern tropical Pacific, southcentral Pacific (e.g., Western and American Samoa), southern Great Barrier Reef, and the Seychelles. The full ecological impacts of this event will not be fully realized for months-to-years, but preliminary reports have been alarming. The acroporid corals, which were the dominant, shallow-water, reef-building corals throughout the Caribbean for at least the past 250,000-500,000 years, were severely impacted, with reports of 90-100% mortality in Florida, Mexico, and Puerto Rico following the 2023 phase of this event. This presentation will provide updates on the latest trends and patterns of this ongoing, record-setting marine heatwave.
Presenter
Dr. Derek P. Manzello
Dr. Derek Manzello is a coral reef ecologist, with a Ph.D. in Marine Biology and Fisheries from the Rosenstiel School of the University of Miami, Dr. Manzello is Coordinator of NOAA's Coral Reef Watch program, an effort focused on the monitoring of coral reef ecosystems through satellite observations. Coral Reef Watch is a part of NOAA’s NESDIS Center for Satellite Applications and Research and uses NOAA and international satellite data to monitor environmental conditions that lead to coral bleaching. From 2001-2021, Derek worked at NOAA’s Atlantic Oceanographic and Meteorological Laboratory in Miami, FL, where he led the development and implementation of the climate change and ocean acidification monitoring of the NOAA National Coral Reef Monitoring Program for U.S. coral reef ecosystems.
Dr. Manzello has published on multiple topics in coral reef ecology, and regularly conducts research that spans the disciplines of biology, chemistry, and geology. His primary research interest is understanding the impact of climate change and ocean acidification to coral reef ecosystems. Manzello has conducted over 1000 scientific dives while researching coral reefs in all U.S. coral reef jurisdictions, as well as international locations in the Pacific (Galapagos, Panama, French Polynesia, Fiji, Palau, Papua New Guinea) and Indian Ocean (Chagos Archipelago).