An expedition led by the Census of Marine Life dived down to the Mid-Atlantic ridge, the vast undersea mountain range running down the centre of the ocean. They found a host of new species, and discovered that many supposedly rare species were living in great numbers:



Acorn worm

This is an enteropneust, otherwise known as an acorn worm. Called the northern pink, it feeds on sediment from the sea floor 2700 metres down.

Acorn worms are one of the so-called missing links in evolutionary history. Although they are worms with no backbone, they have a few features that mark them as cousins of the chordates: animals that do have backbones.

As a result, acorn worms may be able to tell us about how backbones first evolved.




Basket star

It may look like a set of tree roots after an accident with some food colouring, but this is a kind of starfish called a basket star.

Its arms have evolved to form an intricate spiderweb. Krill become trapped in the mesh of tendrils, and the basket star can then eat them.




Deep sea jellyfish

This is a trachymedusa: a kind of jellyfish that only lives in the deep open ocean.

A predator, it feeds on plankton and small crustaceans near the sea floor.

More here.