A deep-sea coral reef covering 6.4 million acres has been discovered off the southeast United States. Researchers working for NOAA and its partners mapped an underwater seascape of coldwater coral mounds the size of Vermont, deeming it the largest deep-sea coral reef habitat discovered to date, according to a paper recently published in the scientific journal Geomatics.
“This strategic multiyear and multi-agency effort to systematically map and characterize the stunning coral ecosystem right on the doorstep of the U.S. East Coast is a perfect example of what we can accomplish when we pool resources and focus on exploring the approximately 50% of U.S. marine waters that are still unmapped,” said Derek Sowers Ph.D. Derek is the Mapping Operations Manager for the Ocean Exploration Trust and lead author of the study.
“Approximately 75% of the global ocean is still unmapped in any kind of detail, but many organizations are working to change that. This study provides a methodology aimed at interpreting mapping data over large ocean regions for insights into seafloor habitats and advancing standardized approaches to classifying them to support ecosystem-based management and conservation efforts.”
The Blake Plateau
For the study, “Mapping and Geomorphic Characterization of the Vast Cold-Water Coral Mounds of the Blake Plateau,” scientists synthesized bathymetric data from 31 multibeam sonar mapping surveys, the largest of which were led by NOAA Ocean Exploration, to produce a nearly complete map of the seafloor of the Blake Plateau, located about 100 miles off the southeast U.S. coastline. The study area is nearly the size of Florida, and stretches approximately from Miami, Florida, to Charleston, South Carolina.
The authors used a standardized system developed to classify, delineate, and quantify coral mound features. This automated system identified 83,908 individual coral mound peak features in the mapping data, providing the first estimate of the overall number of potential cold-water coral mounds mapped in the region. The study documents the massive scale of the coral province, an area composed of nearly continuous coral mound features that span up to 500 kilometers (310 miles) long and 110 kilometers (68 miles) wide, with a core area of high-density mounds up to 254 kilometers (158 miles) long and 42 kilometers (26 miles) wide.
The results also highlight how different regions of the Blake Plateau exhibit large variations in the density, height, and pattern of coral mound formation. Data analyzed included mapping data, and imagery from 23 submersible dives and were collected as part of a coordinated, multi-year ocean exploration campaign involving NOAA Ocean Exploration and several other significant partners.
Million Mounds
The largest area, nicknamed “Million Mounds” by scientists, is primarily made up of a stony coral named Desmophyllum pertusum (previously called Lophelia pertusa). It’s most commonly found at depths between 200 and 1,000 meters (656 – 3,280 feet), where waters have an average temperature of just 4°C (39°F). Without sunlight, coldwater corals survive in the deep ocean by filter-feeding biological particles. While they are known to be important ecosystem engineers, providing shelter, food, and nursery habitat to other invertebrates and fish, NOAA says these corals remain poorly understood.
Studies such as this one provide a better understanding of how populations of corals and other deep-sea species may be related across geographically separated locales (a concept known as connectivity) which in turn can offer insight into the resiliency of these populations. This is important for predicting the impacts of human activities on coral communities and for developing solid plans for their protection.
“For years we thought much of the Blake Plateau was sparsely inhabited, soft sediment, but after more than 10 years of systematic mapping and exploration, we have revealed one of the largest deep-sea coral reef habitats found to date anywhere in the world,” said Kasey Cantwell, operations chief for NOAA Ocean Exploration.
“Past studies have highlighted some coral in the region, particularly closer to the coast and in shallower waters, but until we had a complete map of the region, we didn’t know how extensive this habitat was, nor how many of these coral mounds were connected. This discovery highlights the importance of exploring our deepwater backyard and the power of interagency collaboration and public-private partnerships.”
More at NOAA Ocean Exploration Updates
To read the full scientific paper go to https://doi.org/10.3390/geomatics4010002
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