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We’re continuing our journey to the depths of the Blake Plateau and its fascinating deep-sea coral ecosystem by diving into the ecology that supports life at extreme depths and at the surface. No need to have a background in ecology, just your excitement for all things Under the Sea is required! |
 The mission team is all smiles aboard the Okeanos Explorer in 2018! Image Credit: Art Howard, GFOE, Windows to the Deep 2018 |
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This blog series is all about deep-sea corals and the Blake Plateau. If you’d like to know more, check out our deep-sea corals website page. There, you can find a summary of deep-sea corals and videos that offer a sneak-peek to life under the waves. |
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Thank you for following along on this education series! This is our final installment, but if you loved this information and want to test what you’ve learned, we’re hosting Under the Sea Trivia at Brewlab on February 7th at 7:00pm. In the meantime, scientists are continuing to make new discoveries about corals on the Blake Plateau. In early January, a new scientific publication analyzing the size and shape of coral mounds along the Plateau was released in Geomatics. If you are interested in reading more, you can refer to this press release from the NOAA Office of Ocean Exploration or this article, “Mapping reveals largest known deep-sea coral habitat”. |
How do we study ecology?Ecology is the study of relationships within an ecosystem. In the case of deep -sea corals, we’ll be analyzing their relationships to ecosystems of the deep sea and the surface. (The previous blog posts about the depths of the Blake Plateauand deep-sea coral biology might be helpful background to understand how these relationships work!) Whether you are an avid-fisherman, bird enthusiast, or wildlife lover, the Blake Plateau has something for everyone, from the depths to the surface! Thanks to the special physical conditions in this region and the ecosystem engineering marvels that are deep-sea corals, the Blake Plateau region has incredibly unique habitats. |
Ecology of the deep seaLophelia pertusa: Ecosystem engineer Deep-sea corals along the Blake Plateau can be classified as ecosystem engineers. Like human engineers, ecosystem engineers modify their environment, usually by altering or providing structural habitat in an area.At the bottom of the Blake Plateau, deep-sea corals, Lophelia pertusa in particular, have engineered massive reef systems–or mounds–in areas that would otherwise be barren. Small marine organisms are usually attracted to structures of any kind. In the deep-sea, these corals provide structure for smaller organisms to hide from predators. Within their coral hideouts, squat lobsters, brittle stars, and sea spiders can safely have a lunch break or take a rest without being hunted by larger predators. The abundance of prey among these habitats generally means that predators aren’t far behind. Larger fishes, sharks, and squid will linger amongst the corals, waiting for their own opportunity for a meal! These deep-sea corals have created a structural habitat for an entire ecosystem, from the smallest of herbivores to top predators. |
 Deep-sea corals can support life of all kinds, from the smallest of deep dwellers like this sea spider, to the apex predators such as this shark patrolling for it next meals. Image Credit: NOAA Office of Ocean Exploration and Research |
A hidden nutrient factoryNot only do deep-sea corals structurally influence their deep-sea ecosystem, but they also play a major role in shaping the higher levels of ecology as the backbone of the environment. Deep-sea corals are different from their shallow-water coral counterparts because they don’t need algal inhabitants to sustain their diets. This is because at the bottom of the ocean, food is plentiful for these corals! Their food source comes from the decaying cells of microscopic organisms that sink down from the surface, known as marine snow. Deep-sea corals ingest marine snow, and then excrete waste that can be used as nutrients by algae in the surface zone. So, in addition to providing structure in an otherwise barren ecosystem, deep-sea corals also supply a nutrient source for the bottom-most levels of the food chain. The marine snow that the deep-sea corals have so carefully converted to useable nutrients can eventually end up back in the surface zone. Along the Blake Plateau, the Gulf Stream flows northward and like a vacuum, pulling nutrient-rich water up from the depths. Coupled with the Caribbean waters that the Gulf Stream brings with it from further south, the surface waters above the Blake Plateau are warm, nutrient rich, and highly productive with algae. |
 A squat lobster hangs out on an octocoral. Image Credit: NOAA Office of Exploration and Research |
Ecology of surface watersSurface waters of the Blake PlateauFar above the corals of the deep, the surface waters of the Blake Plateau are also teeming with life. Although there is a separation of 2,000+ feet of water column between them, deep-sea corals are indirectly a part of the surface ecosystem. By cycling the marine snow into useable nutrients, they help support all kinds of life at the surface. Algae, like the sargassum mats that are common in the region, uses these nutrients brought up from the deep to fuel their growth. In the Sargasso sea, sargassum is the ecosystem engineer that provides structure in the barren open ocean! Among the massive mats of algae, juvenile fishes, swordfish, and sea turtles can safely feed while hiding from predators. Just like the deep-sea habitats, the presence of prey often invites predators, and large game fish and sharks are also present amongst the sargassum mats as they search for their next meal. In the surface waters of the Blake Plateau, you can find several commercially and recreationally important fish species, like red porgy, mahi mahi, and triggerfish. Apex predators are also commonly spotted in the Sargassum sea, including blacktip and whitetip sharks. Lastly, the waters above the Blake Plateau are also home to several federally endangered species. The loggerhead sea turtle, South Carolina’s state reptile, and the rare Black-Capped Petrel use the sargasso sea during their long migration periods. |
 A mahi mahi fish swims amongst the sargassum. Image credit: Jason Arnold |
 The elusive Black-capped Petrel cruises above the Gulf Stream. Image credit: Tom Benson/Flickr |
Ocean interconnectednessOn the Blake Plateau, the deep sea and the surface zone are inextricably linked. Small oceanic animals from the surface, such zooplankton, feed the corals of the deep, and corals of the deep recycle nutrients that get swept back up to the surface to fuel the base of the ocean food chain. In ecology, the relationships between the individual animal, population of a species, and communities of several different species are all reliant on each other to create a functioning ecosystem. Recognizing this importance of protected functioning ecosystems, scientists around the world have called for 30% of ocean ecosystems to be protected by the year 2030. In a recently published scientific article, deep-sea corals are some of the most under-protected species in United States waters. Currently, there are no protections on deep-sea corals located off the Blake Plateau. |
 The levels of ecological organization. |
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We’ll continue to keep you posted on all things deep-sea corals, and we hope you continue to stay engaged! |