Science Buddies: "Ask an Expert"

Where might I be able to find/buy tardigrades, antarctic lichen, endolithic life forms, or soil invertebrates? I need to use them in my experiment and am having trouble acquiring any.

Hi,

This sounds like a very interesting project. Tardigrades are commonly found in moss and lichens, so you should be able to find them in a local garden or park. Mosses grow in shady moist places:

http://www.backyardnature.net/mosses.htm

and lichens are commonly found growing on trees and stones, but may be difficult to find if you live in an area with significant air pollution:

http://www.backyardnature.net/lichens.htm

Soil invetebrates are found in any samples of soil:

http://www.earthlife.net/insects/soileco.html

Endoliths grow on rocks:

http://en.wikipedia.org/wiki/Endolith

What are you going to do for your project? Tardigrades, endoliths, and and soil invertebrates are common, but microscopic, so you won't be able to find them until you look under a microscope. Do you have a microscope available? What kind of experiment are you planning to do?

Donna Hardy

I am going to be growing lichen and tardigrades in a simulated Martian environment (hopefully in a nearby college lab). And I found both in a science catalog my science teacher had, so it seems that I don't need to find any anymore. I do have a field microscope at home, but it's not electric or very high tech, so I'm not sure how much help it will be. Thank you for the links, though. I do need the information on them.

Hi,

Thanks for your reply. This is a fascinating project. These organisms grow very slowly. How are you going to measure your results?

Donna Hardy

I was just looking to see what to do about that. I was thinking that I might have controls of both groups and see how many eggs the tardigrades in each group laid, but since the lichen grows so slowly, I'm going to need to find another way. I'll get back to you once I trouble shoot it. Any suggestions?

Hi,

The reason I asked the question, of course, is because lichens and tardigrades grow so slowly.

Here is a description of measuring growth rates in lichens; these grow at a rate of about 0.1 cm/year, so you will need to measure your time zero point very accurately and carefully. There are many species of lichens, and some grow more quickly than others, so it would be important to select the fast-growing species for your science fair project. How are you going to measure the size of your lichens?


http://www.bio.net/bionet/mm/mycology/1 ... 02601.html


Tardigrades are 0.2 to 0.5 mm, which just a small dot by visual observation. You will need to use a microscope to observe and count eggs, but this does seem to be a good way to measure growth rate of these organisms. Do you have a microscope available to use?

http://www.bryoecol.mtu.edu/chapters_VO ... d_Food.pdf

Since you will be comparing growth rates, you will probably want to have a positive control of both fast growing lichen and tardigrades growing under optimum conditions. Then you can compare growth rates of samples growing under Martian conditions. Both lichens and tardigrades can show no growth for long periods of time, so it would be possible to observe no growth in your experiment. The positive control would verify that your samples were alive and capable of growing.

Donna Hardy