Day 2 of Life Beneath the Keel

On Sunday 13 September, at 1800 BST, The Island Trust is live streamingLife Beneath the Keel’ from Plymouth Yacht Haven as part of the Ocean Institute’s virtual Maritime Festival. This is the second in a series of blogs about the marine life we hope to discover then.

Day 2:  1 September 2020 | Sponges

We turn now to the kingdom of animals, the least complex of which, with no nerve nor muscle cells nor sensory organs are the sponges. They were first to branch off the evolutionary tree from the common ancestor of all animals.

A sponge is essentially a tube with many small holes, ostia, to draw in water, from which they obtain food (plankton, dead stuff and poo) and oxygen, before expelling it through larger holes called oscules. Many other animals have a similar diet, and we will look at where it comes from in the final blog on plankton.

  1. The water being expelled from the Sea orange‘s oscules presumably still has enough food left in it to make it worthwhile for the skeleton shrimps to gather round to feed there.
  2. The aptly named Leucosolenia complicata is formed of several joined hollow tubes.

John Hepburn, Ocean Discoverability Project Manager
1 September 2020