Pyrosomes - Drawing: Roger Grace
Image Manipulation: Dave Walsh (C) Greenpeace / Grace / Walsh
A few nights ago, around 11 o'clock, the crew of the Rainbow Warrior heard an urgent whisper - 'Out on the stern, now!'. Crew members. We stumbled up onto the poop deck, pulling on shoes and jackets. Crowding around the railings, we were treated to an amazing light show. Behind the Rainbow Warrior, there was a trail of what looked like dozens of large bright green glowing sausages swirling in our wake! Those near the surface were clear defined shapes, about 30cm long, but those down deeper just looked like glowing irregular green spheres. A squadron of alien craft or perhaps, some of the deep sea extras from the James Cameron movie The Abyss? What the devil was going on?
No, we were not hallucinating. These weird spacey beings are colonial animals called Pyrosomes. Technically they are ocean-going sea squirts or salps. Each of the glowing shapes is a hollow cylindrical tube closed at one end and open at the other. The walls are made up of hundreds of tiny animals embedded in a firm jelly matrix. Each animal has an opening on the outside of the tube which takes in water, which is filtered and passed out another opening to the inside of the tube. They feed by filtering extremely small plants and bacteria from the water. Each animal has one or two light organs which glow green when the animal is suddenly disturbed, such as when passing through the wake of the ship.
These guys were tiny compared to the giant Pyrosomes Roger has seen at the Poor Knights Islands in New Zealand waters. In 1970 he saw several large colonies, the largest being 10 metres long with a "tail" a further 10 metres long. The tube was so wide his dive buddy could fit his head and shoulders inside the opening! Imagine what it would have been like to see it at night, when it was glowing bright green!
- Roger Grace, photographer
- Dave Walsh, web editor
Comments
WOW - what an awesome sight. Pictures probably would not have done it justice - I have tried photographing bioluminescence before - it's vitrually impossible - unless done in a lab.
Hi Roger !
It would be great if you could post some pictures (photographs) or drawings of these Pyrosomes.
Are those creatures in all seas of the world ?
