Unknown plankter from Loch Tallant, July 2000.
This has been identified as a Heliozoan, not an alga, thanks to Steve Durr .
Its characteristics are:
A sphere (approx. 55Ám. diameter) with a thick test of complex structure (interlaced fibres are visible); very numerous setae of various lengths up to approx. 50Ám., with forked ends. The setae were seen to move. The heliozoan ("sun-animal") feeds on algal cells which can be observed inside it.
The following images illustrate these features: the last one shows a heliozoan cell which has ruptured.
It was quite common in the net plankton sample.
Click on the images to see them full-sized, use the 'back' button to return.
Page updated 16/9/01