Despite being frequently encountered by scientists aboard the NOAA Ship Okeanos Explorer, E/V Nautilus, and other exploration vessels, much is left to learn about corals and sponges. Both are sessile (non-moving) organisms, serve as vital resources for other marine life, and can indicate the health of oceanic ecosystems. Learn more about these fascinating animals below!
Corals exhibit some plant-like characteristics, but are actually animal relatives of jellyfish and anemones. They are all within the phylum Cnidaria. All corals are classified as either “hard corals” or “soft corals”. Hard corals have a limestone skeleton, and make up the foundation of a coral reef. They can take a rounded, branching, or flat appearance. Soft corals bind together on a softer structure, and can take the shapes of whips, spirals, and trees. Hard corals can grow as much as ten centimeters per year, the same rate of growth as human hair, but most only grow up to three centimeters each year. Soft corals grow at a rate of two to four centimeters per year. When a coral reef is damaged by a storm, pollution, or by other factors, it may take a significant amount of time before it is able to recover and grow to its former size.
During their 2015 Hohonu Moana expedition, the NOAA Ship Okeanos Explorer discovered and mapped an unnamed seamount in the Central Pacific Ocean Basin (shown in the image above). The ship and scientists are now returning to this region, “Musician Seamounts”, to conduct additional mapping and remotely operated vehicle (ROV) operations over two consecutive cruises. These efforts will be focused north of the Hawaiian Islands, close to the Papahānaumokuākea Marine National Monument (PMNM).
How little is known about our ocean is a fact many agree on, however scientists are actively working to bridge the gap between the unknown and discovery. Right now, the National Oceanic and Atmospheric Administration’s Office of Exploration and Research (NOAA OER) began the third cruise of their current research expedition. Aboard the NOAA ship Okeanos Explorer with remotely operated vehicles (ROVs) Deep Discoverer and Seirios, scientists are well on their way to meeting their goals for this trip. The area undergoing daily exploration is the Commonwealth of the Northern Mariana Islands (CNMI) and the Marianas Trench National Monument (MTMNM) in the western Pacific. The latter area is under NOAA’s protection, based on inferences that there may be unique features within its depths. Gathering baseline data and learning more about what these areas contain will enable effective conservation initiatives.
Scientists on the NOAA Ship Okeanos Explorer were thrilled to see a species of sea star alive for the first time in history. The six-rayed sea star, Rhipidaster (confirmed over phone by Chris Mah from the Smithsonian Museum of Natural History), was found at Supply Reef, an active submarine volcano within the Marianas Trench Marine National Monument. The sea star was last catalogued by scientists over 150 years ago in 1860, when a dead specimen was found. Now, not one, but three of these remarkable sea stars were seen during a June 23, 2016, ROV dive, implying that the species has been living all this time. The fact that this species was seen in an unexpectedly biodiverse region speaks volumes of what else may be awaiting discovery beneath our oceans’ depths. The ship’s mission is far from over. Participating scientists are excited to see what other unexpected discoveries remain to be revealed!