Hi there,
I have one question for you folks.
What is the best way to take samples in fresh or saltwater ?
I use 50ml test tubes with lid (formed like eppendorf tubes, only bigger)
Should I open the lid under water and go close to the bottom ??
For collecting small organisms that live in the water column (i.e. planktic/nektic organisms) I'd prefer a plankton net as this sieves the water and thus concentrates the organisms in your sample. The method of sampling directly into your 50 ml tubes can work, if you can see that the water contains a lot of organisms, as it can be the case with e. g. Volvox algae that you can see already with the naked eye.
But without a plankton net you could take samples of benthic organisms: Take detritus or mud samples from the floor of the body of water you are investigating, or scrape off into your test tubes what grows on submersed stones, plants, wood etc.
God Jakt!
--Betty
Atticus Finch: "You never really understand a person until you consider things from his point of view
- until you climb into his skin and walk around in it."
Lee, N. H. 1960. To Kill a Mockingbird. J. B. Lippincott, New York.
A little surprised that so far only Betty has offered some (good) advice.
I suppose everyone has their own methods, and it will vary depending on what you are looking for. In salt water (or less frequently in fresh water) I will use a small plankton net. Hoping to find interesting creatures by simply drawing a bit of water into a tube/jar is generally not very productive. But I will also go out at a low tide and try to collect some scrapings off of rocks, pier pilings, or any rigid surface. I will collect small amounts of some the finer algae I find.
In fresh water I don't often use the plankton net but either collect directly by hand or use a small scoop at the end of a pole. Generally there are three places you should consider sampling. Try to collect some surface water by lowering a container and letting the surface water skim into the jar. Most productive is the vegetation along the shoreline. Collect some samples. and/or pick up hand-fulls of loose vegetation and debris and let it drip off into the jar with the samples. Then, in a different container, try to collect some samples from the bottom, including some mud and debris that rests on the bottom.
I don't collect large volumes of water, but neither do I use small tubes. If you have live specimens they will last longer if they have some "environment" to live in (especially true of marine samples, which I sometimes try to keep refrigerated. They never survive as long as freshwater samples). From my collected jars I'll use a transfer pipettes to place smaller samples into a petri dish or other shallow container and examine it for specimens that can be placed onto a microscope slide.
