Coral scientists recently traveled to the Galapagos Islands to document coral reef health following the 2016-17 El Niño Southern Oscillation event (ENSO), which bathed the region in abnormally warm waters. Historically, these events have triggered coral bleaching and large-scale mortality, as seen in response to ENSO events of 1982-83 and 1997-98. Interestingly, these same reefs exhibited minimal bleaching in response to this most recent event. Scientists are determining whether this response is due to differing levels of heat stress, or an increased tolerance to warm water in the remnant coral communities.
The study, published in the Proceedings of the Royal Society B, measured changes in the reef framework in several naturally high-carbon dioxide settings near Papua New Guinea. For the first time, scientists found increased activity of worms and other organisms that bore into the reef structure, resulting in a net loss of the framework that is the foundation of coral reef ecosystems.
The new research published online August 10 in Nature Climate Change provides a stark look into the future of ocean acidification – the absorption by the global oceans of increasing amounts of human-caused carbon dioxide emissions. Scientists predict that elevated carbon dioxide absorbed by the global oceans will drive similar ecosystem shifts, making it difficult for coral to build skeletons and easier for other plants and animals to erode them.
Corals live and thrive by maintaining a careful balance between their growth rate and the rate of erosion. Scientists already know the projected increases in carbon dioxide in our global oceans, known as ocean acidification, will slow the rate at which corals build the hard calcium carbonate skeletons that are the foundation of their habitat. A new study published online today in PLOS ONE demonstrates that in naturally highly acidified waters, these coral skeletons will also face increased erosion from microscopic organisms, called bioerosion. The result is accelerated breakdown and loss of reef structures, and potentially the loss of essential habitat.
Researchers with the Global Carbon Budget released their annual update for the global carbon budget in December 2015, revealing carbon dioxide (CO2) emissions from fossil fuels increased slightly in 2014 (+0.6%), but are projected to decline slightly (by est. -0.6%) in 2015. The global oceans serve as a natural buffer, offsetting increased emissions by absorbing an estimated 27% of human-produced CO2 from the atmosphere in 2014. Data collected, in part, from long-term surface ocean CO2 monitoring efforts, funded by NOAA’s Climate Program Office and the Ocean Acidification Program, indicate that the oceans removed about 10.7 billion tons of CO2 from the atmosphere in 2015.
AOML coral scientists participated in a NOAA National Marine Fisheries Service-led project to document coral spawning in the Florida Keys National Marine Sanctuary during August & September 2015. The project aims to measure spawning success for two imperiled Caribbean species, elkhorn coral (Acropora palmata) and mountainous star coral (Orbicella faveolata) in the Florida Keys. The team collected gametes from both species to be used in experiments that aim to improve the understanding of factors that may enhance the likelihood of coral larvae to survive and settle on the ocean floor. Experiments will also assess impacts of current and future global environmental changes, such as ocean acidification, on these vulnerable early life stages of corals. Click on the image below to view a video of a spawning mountainous star colony.
Photo and Video credit: NOAA
Members of AOML’s Acidification, Climate, and Coral Reef Ecosystems Team (ACCRETE) recently traveled to two remote reef locations to expand the National Coral Reef Monitoring Program’s (NCRMP) network of sentinel climate and ocean acidification monitoring sites. The newly established sites, located in the Flower Garden Banks and the Dry Tortugas, will provide researchers with additional data and insights into the ocean’s changing chemistry and the progression of ocean acidification, as well as the ecological impacts of these variables across the Caribbean basin and the Gulf of Mexico.
A team of researchers, including scientists from AOML and the University of Miami, set sail June 19th on a research cruise aboard the NOAA ship Gordon Gunter to provide increased understanding of ocean acidification and its drivers along the U.S. East coast. The cruise, which is part of a larger effort supported by NOAA’s Ocean Acidification Program, investigated near-shore and deep waters, and provided researchers with more detailed information about changing ocean chemistry in different environments.
This summer, AOML will be diving into a new outreach initiative with the Central Caribbean Marine Institute, a coral reef research organization based in the Cayman Islands. From June through August, NOAA oceanographers from AOML will give a series of talks on various oceanographic topics to the institute’s staff and students participating in the National Science Foundation’s (NSF) Research Experiences for Undergraduates program at the institute’s Little Cayman Research Centre (LCRC).
A study of Galápagos’ coral reefs provides evidence that reefs exposed to lower pH and higher nutrient levels may be the most affected and least resilient to changes in climate and ocean chemistry.