A Sea Gooseberry

Today's Guardian Country Diary is about this sea gooseberry Pleurobrachia pileus that we found stranded on the sands at Seaburn beach near Sunderland. When I scooped it up into this container and added sea water it was still alive but it died before I could return it to the sea.

Sea gooseberries are correctly called Ctenophores but in these closer images you can see why they are also known as comb jellies - there are eight rows of beating cilia, arranged like combs, along their flanks, providing propulsion and maintaining their position in the plankton.

Sea gooseberries are predators, trailing a pair of tentacles that trap planktonic fish larvae and the larvae of crabs and molluscs.

They are planktonic drifters and are quite often stranded on beaches, especially when there is a rough sea that sends waves high up the beach. This rather forlorn specimen reminds me of a deflating airship but when they are alive their are exquisite creatures. They are as transparent as glass but this bands of beating cilia create waves of green and blue iridescence along their flanks.

For a closer look at sea gooseberries, with tentacles extended and some movie, see

http://cabinetofcuriosities-greenfingers.blogspot.co.uk/search/label/sea%20gooseberry

and 

http://beyondthehumaneye.blogspot.co.uk/2009/09/sea-gooseberries.html

and


http://beyondthehumaneye.blogspot.co.uk/2009/09/sea-gooseberry-videos.html

Sea Gooseberries

Sea gooseberries, rescued from the beach at Warkworth

Each animal is as transparent as glass, although the tentacles carry a hint of purple

Eight rows of beating hairs, arranged like combs, provide the propulsion. The pink blobs are retracted tentacles

A sea gooseberry swimming left to right and extending one of those lethal tentacles.

A tentacle fully extended, danging below the animal to catch prey,

which is then reeled in

A swimming sea gooseberry, propelled by the rows of 'combs' (which is why these are sometimes called comb jellies), and training tentacles

The rows of cilia make these very manoeuvrable animals -

this one of spinning on the spot, trailing tentacles

Every wave that lapped onto the sandy beach at Warkworth on the Northumberland coast this afternoon washed up scores of blobs of glistening jelly, each about the size of a currant – about 5mm. in diameter. When I scooped some up into a plastic pot and added sea water they turned out to be sea gooseberries, otherwise known as comb jellies. These tiny predatory animals drift in the plankton, suspended by eight rows of constantly beating hairs arranged like combs (called ctenes) and dangle a pair of long tentacles that catch small prey items and draw them up into the animal’s mouth. They are exquisite little organisms, as transparent as glass and flashing with electric blue and green iridescent colours generated by their beating hairs when they catch the sunlight. There must have been tens of thousands of them drift in the plankton just offshore this afternoon. I managed to get some home alive and took some pictures under the microscope, which you can view over at http://beyondthehumaneye.blogspot.com/2009/09/sea-gooseberries.html and I've posted some videos at http://beyondthehumaneye.blogspot.com/2009/09/sea-gooseberry-videos.html