help collecting plankton and protists for microscopy

[walter23]

I finally got a decent microscope and wondered if there are any resources out there to give information on collecting a variety of protists or microscopic plankton from coastal waters. I've collected some water from a beach with a lot of kelp and sea lettuce, and found some interesting like diatoms, filamentous algae, and some ciliates, but would love to figure out how to get concentrated amounts of interesting and varied things. I was thinking of filtering water through a coffee filter or something and then trying to collect things from the filter, but not sure if this is the best approach.

any suggestions, I'll do some trial and error this weekend but any tips would be appreciated!

thanks[/li

[Franz Neidl]

Hello Walter,

Plankton fishing is a good idea! I personnaly enjoy it very much.
I would buy (via Internet) a small plankton net for students with a mesh size from 64 microns. The coffee filter you can use at your home to concentrate your "plankton soup".
If you are in Germany I could indicate a good shop (per privat mail), about America I dont know a good adress.
There are also many articles in the Internet "how to make a plankton net". But it is better to buy one.

Franz

[Bruce Taylor]

Remember that protists are not confined to the water column. There are very interesting organisms in sandy sediments, as well (interstitial ciliates, especially). The best place to look for samples (according to Psiwavefunction, who is currently working at a marine facility) is "the stinkiest sand you can find."

The standard extraction method was developed by Gotram Uhlig, and described here: http://link.springer.com/article/10.1007/BF01612370

A sediment sample is placed at the bottom of an open-ended tube, the bottom of which is covered with nylon mesh. This is then covered with a layer of cotton wool. The lower end of the tube is placed in a dish containing a small amount of filtered seawater. The upper part of the tube is then filled with ice. As the ice melts into the sediments, the little critters flee downward and are collected from the dish.

Here is a drawing of Uhlig's apparatus, from Philip G. Carey's Marine Interstitial Ciliates.

[walter23]

Great advice - thanks! This will definitely help. I like the idea of using a net, might help catch and concentrate free-swimming plankton that might otherwise be hard to find. The ice extraction method is a novel idea to me and worth trying. Plenty of stinky sediment in various bays and estuaries around here.

Last night I discovered the dirt in a particularly wet flowerpot is filled with rotifers. Fun stuff.