Deep Sea Corals: The depths of the Blake Plateau
Come along as we uncover the wonders of the deep!
Over the next few weeks, we’re talking deep-sea corals and the Blake Plateau.
Follow along with us during this educational series and test your knowledge at our upcoming under the sea trivia event in February (might want to pay close attention to the bolded text throughout!). No need to have a background in geology or oceanography, just an excitement for all things Under the Sea!
We begin our journey to the depths of the Blake Plateau—and its fascinating deep-sea coral ecosystem—by diving in to the geological formations and oceanographic currents that make this area exceptional.
Where in the world is the Blake Plateau?
The Blake Plateau is an elongated relatively flat expanse of the continental shelf along the southeastern coast of the United States. This fascinating undersea geological feature was created 208 million years ago, during the late-Triassic period, as the supercontinent Pangea began breaking into the American and African continents.
The rift continued to separate the two continents for the next 200 million years, forming the Atlantic Ocean. The sea floor of the Atlantic Ocean is about 11,692 feet deep on average, making the Blake Plateau seem shallow at only 2,600-3,200 feet deep. It extends from Cape Hatteras, North Carolina to Bahama Banks, beginning about 200 miles off the coast and spanning 80-100 miles across.
How did the Blake Plateau get its name?
You may be wondering: who is Blake? But, it’s actually more about what is Blake.
In the late 1880s, a steamer ship called the Blake completed several oceanographic expeditions along the southeastern coast of the Atlantic Ocean. During these expeditions, crew members were collecting valuable data, including conducting deep-sea trawls along the ocean floor. These trawls resulted in the discovery of coral species along the bottom of the Atlantic Ocean—a place that was previously considered barren. Ultimately, the plateau was named after the steamer ship by which many of these initial incredible discoveries were made.
What kind of habitat exists along the Blake Plateau?
Oceanographers describe undersea ecosystems in terms of temperature, depth, and pressure, so that’s what we’ll do here, too. The Blake Plateau contains many different ecosystems, which exist on the seafloor and near the surface.
Ranging from 0 to 650 ft beneath the waves, the surface zone along the Blake Plateau is where visible sunlight can penetrate. Pressure at this depth is minimal but ranges from 1 atmosphere to 20 atmospheres. For context, being subjected to 20 atmospheres at 650 feet deep is like having an elephant stand on your head!
The surface zone of the Blake Plateau remains relatively warm (>70 °F) year-round, thanks to the world’s fastest-moving current, the Gulf Stream, which flows at 5.6 miles per hour. The Gulf Stream carries water from the Caribbean north toward New England. As the Gulf Stream treks northwards along the southeastern coast of the United States, it brings warm water from the equatorial regions. This movement pulls nutrient-rich water up from the depths of the ocean towards the surface zone, where the nutrients and sunlight fuel algae growth.
Life in the surface zone is abundant, thanks to the sunlight that can support the free-floating algae that live there. Algae, like plants, can conduct photosynthesis and are often at the bottom of the food chain that provides energy to all other living organisms in that zone. Sargassum is a critically important floating algae that provides an ecosystem and energy source for many other ocean species. In the surface zone of the Blake Plateau, several recreationally and commercially important fish species thrive, such as bluefin tuna, swordfish, and grouper. Other species are supported by this productive ecosystem, too, including loggerhead sea turtles, bottlenose dolphins, and whale sharks.
The sea floor of the Blake Plateau is over 2,300 feet below sea level. At these depths, pressure is immense, and reaches over 70 atmospheres! Temperatures at these depths are colder than at the surface, averaging 39°F. Although the depths of the Blake Plateau are subject to harsh temperatures, no sunlight, and incredible pressures, life still thrives.
Since no phytoplankton can exist at these depths, deep-sea creatures get energy by feeding on marine snow that falls down from the surface zone. Marine snow is the microscopic decomposing bodies of plankton floating down from the surface zone. Even at the deepest depths, life is indirectly still supported by our sun!
Thanks to the nutrients supplied by marine snow, the ocean floor supports a variety of marine life. Deep-sea corals create a rocky habitat along the usually soft-bottom sediments, which supports several other species. Squat lobster, monkfish, and sea stars are some of the fascinating deep-sea creatures that live amongst the corals at the bottom of the ocean.
At this depth, the pressure is far too intense for humans to scuba-dive, so to observe what’s happening on the sea floor of the Blake Plateau, scientists dive inside vehicles called submersibles. Submersibles visiting the Blake Plateau carry up to three divers and a round-trip takes as long as 7 hours!
Thanks to the bravery of scientists from all over the world, we’ve been able to catch glimpses of an abundance of life lurking beneath the waves. Take a look at some footage from their explorations of the Blake Plateau!
Go further on your discovery expedition and check out our deep-sea corals webpage. There, you can find a summary of deep-sea corals and videos that offer a sneak peek at life under the waves. Stay tuned for all things deep-sea corals and we’ll ‘sea’ you next time!