An international team of researchers has demonstrated that cold-water coral mounds located in the southern Gulf of Mexico store significant amounts of carbon over geological timescales. Published in the journal Coral Reefs, the study involves CCMAR through Lélia Matos, whose previous work formed the scientific basis for this new assessment that highlights the role of deep-sea ecosystems in the long-term carbon cycle.
Understanding where and how carbon is stored is essential for improving climate models and our knowledge of the Earth's carbon cycle. While coastal "blue carbon" ecosystems such as seagrasses, mangroves and salt marshes have received increasing attention in recent years, the contribution of deep-sea habitats remains far less understood.
The new study, led by Luis Greiffenhagen (AG Hebbeln, MARUM), focuses on cold-water coral mounds located in the Campeche Mound Province, in the southern Gulf of Mexico. These large seabed structures - formed over hundreds of thousands of years by reef-building cold-water corals - act as natural repositories where both organic and inorganic carbon accumulate and become buried over geological timescales.
To investigate this process, the researchers combined sediment core analyses with high-resolution bathymetric mapping to reconstruct approximately 250,000 years of carbon accumulation across the coral mound province. Their results reveal carbon accumulation rates between three and nine times higher than those of the surrounding seafloor. By scaling these findings to the entire mapped area, the team estimates that the Campeche Mound Province stores approximately 18.5 million tonnes of carbon, locked away for millions of years.
The chronological data and palaeoceanographic reconstructions developed in previous studies on sediment cores collected in the Campeche Mound Province were not only incorporated into this research, but were also crucial in establishing the timescale used to quantify carbon accumulation over the last 250,000 years.
By acting as long-term carbon reservoirs, cold-water coral reefs may play a more significant role in the global carbon cycle than previously thought. These findings underscore the importance of continuing to investigate these vulnerable and as yet largely unexplored habitats, whilst also demonstrating the value of international scientific collaboration and the integration of data and knowledge gathered over several years to deepen our understanding of how marine ecosystems function and their role in regulating the climate.
The study, Large-scale carbon storage in the deep-sea through cold-water coral mounds off the Campeche Bank, Gulf of Mexico, was published in the journal Coral Reefs.
