Deep Sea Corals of the Gulf
This blog was written by Hannah Leis, Healthy Gulf's Fisheries Associate.
Welcome to GRN’s deep sea coral (DSC) blog series! Each week, I will bring you a new species of DSC to learn about, and often a species of fish or other marine organism that is associated with DSCs. There are already over 3,300 species of DSC that have been discovered by scientific expeditions, with new ones being identified and named with each trip.
Unfortunately, deep sea corals in the Gulf are under threat from warming waters, oil spills like the BP disaster, certain fishing methods, and other factors. Right now, the Gulf of Mexico Fishery Management Council is considering new protections for some of our most precious corals. We’ll keep you informed on how you can play an active role in protecting these corals.
Before we start with specific species of DSCs, here is some background about these animals.
- Coral are in fact animals! Coral structures can be as small as one polyp (the name of the animal that makes up coral) to thousands or million of polyps attached together, called a colony, to make up larger structures and reefs. An individual polyp can be anywhere from ¼ inch long, to 12 inches long. While they can be found individually, they are often found in colonies or reefs where many polyps of the same and different species grow together.
- DSCs are corals that grow at depths deeper than 164 ft (50 m), and have been found as deep as 6,000 ft (1830 m) where water temperatures can reach 30.2° F (-1°C). At these depths, sunlight does not reach the coral. As a result, DSCs must rely on different methods of food consumption than shallow water corals. Shallow water corals get food from a symbiotic relationship with an algae called zooxanthellae that live inside the tissue of the coral and produce food for the polyp through photosynthesis. There is not enough, or any, sunlight reaching deep sea corals for them to have this same relationship, so instead DSCs get nutrients by consuming small pieces of food that float by them.
- The relatively little information we have on DSCs comes from remotely operated vehicles (ROVs) able to reach the depths the organisms dwell in, fitted with lights so that we can see what we are looking at (see image below). ROVs are our only window which we can look into to see these organisms, as many of them dwell at deeper depths than scuba divers can reach. Researchers will spend weeks out at sea using this technology to assist them in collecting both images and samples about DSCs and other organisms associated with them.
- Additionally, these corals provide us benefits. Many species of fish that are both commercially and recreationally important rely on DSCs during part or all of their lifespans to provide food and shelter. Secondly, these corals can live for hundreds or thousands of year and so they provide information about what oceans of the past used to look like. There is the potential for deep sea corals to unlock medical advances as well. Deep sea corals live and grow for thousands of years, and some scientists speculate the traits that enable them to grow for such long periods of time may have uses in medicine.
This blog series will start by exploring different kinds of deep sea corals, and then move into more specific species of coral that can be found in the deep sea in the Gulf. Stay tuned to learn more about these fascinating creatures and the other animal that live with them.
Click here to see a video of deep sea corals from the National Oceanic and Atmospheric Administration (NOAA).
To explore the various species of coral that exist around the world, including in the Gulf of Mexico, click here to visit NOAA’s interactive Deep Sea Coral map.
Hannah Leis is GRN’s Fishery Associate.