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Robotic Deep Sea Explorer Uncovers Treasure Trove of Freaky Marine Life

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Last month, scientists aboard the NOAA ship Okeanos Explorer visited a poorly-explored deep sea area about 940 miles west of Hawaii. From giant sea spiders and rare snailfish through to comb jellies and glass-like corals, these are some of the weirdest critters we’ve seen in a while.

Laulima O Ka Moana, as the expedition was called, took NOAA to a region around the Johnston Atoll. From July 7 to August 2, 2017, NOAA scientists explored these deep waters using a pair of remotely operated subs, Deep Discoverer and Seirios. The expedition is part of the three-year CAPSTONE mission, an initiative to collect deepwater data in support of science and management decisions in and around protected US marine areas. To that end, the scientists investigated vulnerable marine habitats and seamounts, carefully documenting the marine life forms as they were encountered.


As usual, the expedition resulted in some fairly remarkable discoveries. Here are some highlights.

Creepy Creatures of Laulima O Ka Moana

Glass sponge


Also known as hexactinellids, glass sponges have skeletons made of silica, the same material used to make glass. They live attached to hard surfaces and suck up bacteria and plankton from the surrounding water. The skeleton of the glass sponge, along with various chemicals, provide defense against many predators. It’s definitely one of the most unusual organisms on the planet.

A “turbocharger” glass sponge

This one’s called a “turbocharged” glass sponge on account of the distinctive tubes arising along its upper edge.

Gangly sea spider


Looking like something out an Alien movie, this large sea spider, a marine arthropod, was seen at 1,495 meters (4,905 feet).



A possible new species of deepwater snailfish in the family Liparidae, this critters was seen at a depth of 2,55 meters (8,380 feet). These tadpole-like fish can be found from the Arctic to the Antarctic, but very little is known about them. Snailfish are well suited for deep waters, featuring well-developed sensory pores on their heads.

Comb Jelly


A stunning shot of a translucent comb jelly, taken at a depth of about 600 meters (1,970 feet).

Cusk eel


A cusk eel hangs out above the seafloor at about 1,840 meters (6,035 feet) depth, basking in the glow of Deep Discoverer’s lights.

Slime star


This particular slime star, the pterasterid Hymenaster, measures more than four inches (10 centimeters) wide and has a soft, gelatinous surface held up over its body surface. These strange stars can spew mucus as a defense when harassed.

A stalked glass sponge


A close-up of a very dandelion-looking stalked glass sponge. The red coloring at its anterior portion is produced by instruments aboard the ROV.

Tiny jelly


A very tiny cnidarian, a jellyfish known as Aegina, is seen feeding on the polyps of bamboo corals.

Dandelion siphonophore


This dandelion siphonophore was the first one observed by NOAA explorers on the expedition. “Found at approximately 2,530 meters (8,300 feet), we were able to see the feeding tentacles extended around the animal like a spider web as well as the pulsating nectophores, found just below and around the ‘float,’ which helped to keep the central body suspended,” noted NOAA.

Black corals


Black corals like this one (Bathypathes) were not seen in the sedimented area where the dive began, but became more common as Deep Discoverer explored the region’s rocky ridge and crest.

Brown nudibranch


The NOAA researchers considered this large brown nudibranch to be among the most unusual animals observed during the expedition. This specimen, which measures about four inches (10 cm) in length, was found a depth not typically seen for these creatures. Nudibranches are often confused with sea slugs, but they’re actually soft-bodied mollusks that shed their shells after a larval stage.

Farreid glass sponges


This gorgeous photo shows a pair of farreid glass sponges at a depth of 2,360 meters (7,740 feet) depth. Corals were also present, but in lower abundance. Iridogorgia and bamboo coral can be seen in the background.

Precious pink Hemicorallium


An amazing specimen of pink Hemicorallium, a type of coral. This photo was taken at a depth of 2,400 meters (7,875 feet) when the Hemicorallium had most of its tentacles drawn in.

Incredible corals


Iridogorgia and bamboo coral can be seen in the foreground, while octocorals appear further back. This photo was taken near the East “Wetmore” Seamount.

Sea star eating corals


The right side of this bamboo coral has been stripped clean by this sea star at a depth of 1,510 meters (4,955 feet) on “Pierpoint” Seamount.

Another fantastic mission has come to an end, but the good news is that NOAA will be exploring the Musicians Seamounts, a group of deep sea mounts in the North Pacific, from September 6-30. We’ll be sure to track their progress.