The Sea Finger (Alcyonium acaule) is a species of soft coral found in the northern Atlantic Ocean. Its distinctive finger-like form and bright coloration make it a striking presence on the seabed.
Description and Characteristics
The Sea Finger, Alcyonium acaule, is a colonial organism, meaning it is composed of many individual polyps that work together as a single entity. These polyps are small, typically less than 1 cm in length, but they form large, fleshy colonies that can reach up to 20 cm in height. The colonies are typically bright red or orange in color, but can sometimes be white or yellow. The Sea Finger’s surface is covered in small, finger-like projections called “polyps,” each of which has a mouth surrounded by tentacles.
Habitat and Occurrence
The Sea Finger, Alcyonium acaule, is a common sight in the waters of the north-east Atlantic Ocean, where it is found from the Arctic Circle to the Mediterranean Sea. It is particularly common in the British Isles, where it is found on rocky reefs and in sheltered bays. The Sea Finger prefers to live in cold, clear water, typically at depths of between 10 and 100 meters, making it a common resident of the infralittoral and circalittoral zones.
Taxonomy
The Sea Finger, Alcyonium acaule, belongs to a large and diverse group of marine invertebrates known as the Anthozoa. It is classified within the Class: Octocorallia, which encompasses corals that possess eight tentacles. This class is further divided into multiple orders, and the Sea Finger belongs to the Order: Malacalcyonacea, which is characterized by the presence of a hard, calcareous axis within the colony. Finally, the Sea Finger is a member of the Family: Alcyoniidae, a group of soft corals that lack a true skeleton.
Feeding
The Sea Finger, Alcyonium acaule, is a carnivore that feeds on small organisms that drift by in the water column. Its polyps extend their tentacles to capture food, including brine shrimp nauplii, dust food, and plankton. These tiny prey items are then transported to the mouth of the polyp, where they are digested.
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