Description: When I pick things out of the water off docks, I often run across colonies of ciliates*, growing on other organisms. These colonial ones grow connected together, with a central stalk and side branches, off which the individual cells form in a fan (the white feathery structure in the image is the colony). I've also seen other growth forms, including a beautiful one in the shape of a wine glass, but I wasn't able to get a picture of that one.
One neat thing about the ciliate colonies is that when I've poked part of the colony the whole colony curls up and contracts. How connected are the cells? Do they share nutrients, or electrical signals, or is it just that when one contracts the mechanical disturbance bothers the other individuals, so they contract too? Granted, my ability to poke part of a tiny colony is minimal, so maybe it's just me disturbing them.
The individual ciliates in the colonies look a bit like vorticella, which has a ring of beating hair-like cilia that it uses to feed, and a body supported by a long stalk that can spring back when the cell is disturbed. They feed by capturing even smaller organisms with the water flow generated by the beating ring of cilia.
The ciliate colony shown here was about 0.95 mm from base to tip. It is growing on a bryozoan (Bugula neritina; reddish), which is itself a colony, but of animals rather than single cells. Much like the ciliates, each individual in the bryozoan colony feeds by using a crown of ciliated tentacles (not visible here) that generates a flow of water from which they capture food particles. Each individual within the bryozoan colony is composed of many cells, and has muscles, a gut, and a nervous system; the individuals share nutrients and neural signals.
There are neat parallel in colony form and function between the animals and the ciliates that are ~1000 times smaller, but it strikes me that there may also be parallels between the ciliates and sea fans that are ~1000 times bigger than the bryozoans. Perhaps like the sea fans, these vorticella-like colonial ciliates orient to face the water flows generated by their hosts, the bryozoans, so that they can get more food carried to them. Would be neat to see how they develop and change as the organisms around them grow and change.
*Ciliates are very complex unicellular organism that typically move and feed with beating hair-like extensions of the cell (the cilia).
Page creator's name: Mickey von Dassow
Page creator's contact info: Through IGoR contact page.
Created: 02 Aug 2014 18:56
Updated: 06 Jan 2015 21:38