The green blob from the North Sea

Every year in early spring I find these green, slimy, globular things attached to seaweed in the North Sea at the Dutch coast, especially in the Oosterschelde. They are about 1 cm in diameter and macroscopically they show no clear internal structure. I never find them in summer, they seem to have disappeared by then. For years I did not know what they were, until my friends Martine Van Audenhove and Karel Wouters solved the problem: these are egg-capsules of a polychaete, Phyllodoce maculata. See http://www.glaucus.org.uk/polychaet.htm, http://communities.zeelandnet.nl/data/strand/index.php?page=13&showpage=55493 and http://www.seamasters.be/bio/borstel/dieseltreinworm.htm.

green blob attached to Fucus

Green blob attached to Fucus vesiculosus.

Left: detailed view of green blob. Right: inside the blob is a gel full of white, egg-like beads.

This is what the egg-like structures look like under the microscope.

While concentrating on the mystery, Martine slowly becomes a green blob herself... and creates a new mystery: the fish tank invaders!

Photographs: Jan Bosselaers

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