Coastal Cnidaria

Phylum Cnidaria includes jellies, anemones, and coral, all of which may be found at coastal communities like Southern Hydrate Ridge, Slope Base, and the 600 m Oregon Offshore site.

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Poralia rufescens (No Common Name)

The Poralia rufescens was seen at Slope Base. It was found floating in the water column at 2867 meters. Another one was spotted swimming among the dust kicked up by ROPOS at about 2900 meters. Photo Credit: NSF-OOI/UW/CSSF; Dive 1757; V14.

Very little is known about this jellyfish, except that it lives in deep waters. It was previously spotted in the Atlantic Ocean at Lost City, and in the Pacific Ocean off the coast of Washington State and Canada at the site for the RSN underwater observatory. It is a flat disc, with eight tentacles in the center, and thin, wispy appendages around the outside of the disk. When it moves, it can undulate from flat to dome-shaped. It is red or pink in color, sometimes appearing brown from a distance.

Reference:
Marine Life Field Guide (Neptune Canada)

Corallimorph anemone (Corallimorphus sp.)

This Corallimorph anemone was spotted on the seafloor at Southern Hydrate Ridge at a depth of 774 meters. Photo Credit: NSF-OOI/UW/CSSF; Dive 1772; V14.

The corallimorph anemone or mushroom anemones are similar to sea anemones. They lack a calcareous skeleton but also lack the long feeding tentacles that a sea anemone has. They often have a flattened oral disc with a smooth, bumpy, or fuzzy appearance. Mushroom corals have symbiotic zooxanthellae in their tissues. They come in a wide variety of colors and can be solid, spotted, or striped. Neptune Canada’s guide included it in the “sea anemone” category because of similarity, but it belongs to another order: Corallimorpharia.

Reference:
Marine Life Field Guide (Neptune Canada)

Dinner Plate Jelly (Solmissus sp.)

Dinner plate jellies can grow to be up to 20 centimeters in diameter. They are found in the water column at depths of 700 to 1000 meters. They were seen frequently at Hydrate Ridge in the water column at various depths. Photo Credit: NSF-OOI/UW/CSSF; Dive 1774; V14.

Dinner plate jellies are round and fairly flat, they resemble a dinner plate in size and shape giving them their name. They have long, string-like tentacles that come off from around their bodies and float around them. They are unique in that they actively hunt for prey as apposed to waiting for prey to pass by. They feed on gelatinous zooplankton, other jellies, and copepods.

Reference:
Marine Life Field Guide (Neptune Canada)

Venus Flytrap Anemone (Unknown sp.)

The Venus flytrap anemone was seen at Slope Base at a depth of 2900 meters rooted in the sediment on the seafloor. It was only seen twice in one dive. They do not appear to be very common. Photo Credit: NSF-OOI/UW/CSSF; Dive 1757; V14.

The Venus Flytrap Anemone resembles the carnivorous plant found on land. We know it is member of the family “Actinoscyphiidae”, but we don’t know how many species there are. They can be found in every ocean basin attached to a variety of hard substrates on the seafloor. This anemone waits for food to drift into its tentacles lined with stinging needles called nematocysts. The Marine Life Field Guide contained an entry on a Venus Flytrap Anemone, but was unable to identify its genus and species. It says that it is a member of Hormathiidae, which is a family of sea anemones in the class Anthozoa. However, this picture in the Guide looked different from the species that we found.

References:
Marine Life Field Guide (Neptune Canada)
http://www.deepseanews.com/2008/10/the-27-best-deep-sea-species-18-venus-fly-trap-anemone/
http://ocean.si.edu/ocean-photos/venus-fly-trap-anemone-gulf-mexico

Deep Sea Anemone (Unknown sp.)

This anemone was found on a rock at a depth of 775 meters. Anemones can range in size from 1.25 centimeters to 1.8 meters. This anemone looked to be about 10 centimeters in diameter. Photo Credit: NSF-OOI/UW/CSSF; Dive 1758; V14.

Anemones are sessile polys; they spend most of their lifetime attached to rocks or coral reefs. They attack via an adhesive foot. Their mouth is in the middle of an oral disc surrounded by tentacles armed with cnidocytes. Cnidocytes contain stinging nematocysts. Due to the fact that they are sessile they have to wait for their prey to come to them. Once their prey is close enough they stretch out their tentacles and grab their prey pulling it into their mouth. Anemones can reproduce sexually or asexually by budding, binary fission, and pedal laceration. The anemone we found was purple in color and only had tentacles on the top around its oral disc.

Reference:
Marine Life Field Guide (Neptune Canada)

Voragonema pedunculata (No Common Name)

This jelly was found at Southern Hydrate Ridge at a depth of 788 meters. The diameter of these jellies have been measured up to 4 centimeters. Photo Credit: NSF-OOI/UW/CSSF; Dive 1769; V14.

The Voragonema pendunculata is a small red jellyfish that has 1000-2000 very fine tentacles. It also spends its entire life in the water column; it does not go through a sessile phase in its development, which makes it different from other jellyfish.

Reference:
Marine Life Field Guide (Neptune Canada)

Mushroom Soft Coral (Anthomastus sp.)

This coral is not rigid, rather this coral is soft meaning that it does not produce a calcium carbonate skeleton. The soft coral has been found at Southern Hydrate Ridge and the Pinnacle at depths around 775 meters deep. Photo Credit: NSF-OOI/UW/CSSF; Dive xxx; Vxx.

This coral is not rigid, rather this coral is soft meaning that it does not produce a calcium carbonate skeleton. They are unlike the rigid, or hard, corals that thrive from the sunlight; soft corals thrive in regions with less light and high nutrients. They typically feed on any free floating food in the water column. This type of mushroom soft coral is pink with a circular and oblong shaped fleshy body with tentacle like projections coming out of it. The corals are found on the carbonate cobbles found on the sea floor.

Reference:
http://www.realmonstrosities.com/2012/03/mushroom-soft-coral.html

Pom Pom Anemone (Liponema brevicornis)

A Pom Pom anemone on sedimented seafloor 8530 ft beneath the oceans’ surface. Credit: UW/NSF-OOI/WHOI; V19.
The Pom Pom Anemone actually looks like a pom pom. It has a circular or oblong shaped body and is covered with many short tentacles shaped in a whorl formation. The anemone does not attach to any substrate, and it has the ability to roll along the sea floor like tumbleweed because ocean currents propel it. The Pom Pom Anemone’s diet usually consists of plankton, krill, small crustaceans, and other organic particles; it is also a predator and a scavenger.

Reference:
Marine Life Field Guide (Neptune Canada)