DIY
Bringing Soil Animals to Life
How can we involve and educate people as to the wonders of life in the soil? While we have filmed every other frontier, our earth has been impenetrable.
How can we bring the animals in the soil to life? Here is the proper gear for extarcting small soil creatures. They are called Tullgren Funnels. However these would cost about £500 So thought I'd do it on the cheap..
When trying to explain to some youngsters around the house, I picked up a lump of soil, and said: "Inside this, there are lots of little animals which I can show you. If I can get these creatures to move out of the soil I can show you what they look like" There are thanks to several people for helping me to overcome some challenges - Keith for getting the creatures onto tissue, Nancy for tin can idea, and Rob for suggesting to strap digital microscope to binocular microscope.
Recipe
Ingredients
Any lump of soil whether cold of clay, leaf litter or lump of lawn..
Empty bottle 2 litre cola
Tin can
1 Light Bulb 50-100 watt, NOT energy saving! You need an old one that throws off some heat.
Water
Binocular Microscope (£100) , or 20-200X digital microscope that show on PC screens £20+)
Retort Stand (or just put upturn the Cola bottle in a jam jar) to hold Cola bottle.
Gauze, either metal or cotton
Method
1. Use a tin can as a little auger (soil sampler). Cut off both ends (some cans netter to remove both ends cleanly.
Push it into the ground as you want to sample down about 2 inches. Swirl tin round with your hands to sever sample from rest of soil. Pull this out of the ground, then push the clod to the other end of the can. Now, what was the surface is showing from the bottom of the can. Put some cotton gauze over the end with the soil surface and tape it on. Then put into this...
2. Extraction Apparatus. Cut a large cola bottle horizontally in half. Tip it upside down so the cap is at the bottom and arrange a
way to hold it steady - like the jam jars here and retort stand. Upturn the tin can so that the soil surface is now face down. Put an old fashioned bulb about 2 inches above. The tin can is important to hold the soil, as it conducts heatr away and allows a temperature gradient from top to bottom to build up. It is that temperature difference that drives the arthropods away from the heat, down tohe bottle and into th vials with water below.
3. Put light on for several days. I used to do this with 60 funnels for a week or two on end, and never worry about the electrics and possibility of of a fire. Now I am careful to leave one bulb on overnight. The creatures come out at different rates. If you can measure the temperature, you could do with 40+ on the surface and a 10 degree difference from top to bottom.
4. The vials hold the creatures for a few days. Use the endoscope microscope to look into the vial to see what is going on the surface of the water. The miniscus holds the creatures together. When you are ready, pour out the contents on to a tissue in a petri dish
Use a (20-200X digital microsope) - where you can view the image on screen. It is easier to stay in focus, and move the paper round. And the creatures walk around much more like they are in the soil, some burrowing through, others climbing over ridges. And they are colour, so very much more like the conditions in which they live, and we can see them move as they would in the soil.
Have a look at sample No 1, and 2 based on the extraction process described above, collected on the first day.
First to arrive are springtails, a few days later the oribatid mites appear. There are different stages in their life going from nymphs to hard nut adults, which eat into leaves. The Soil Report 2007 by CS noted that "highest catches of mites were found in plots at which rainforest was highest, while springtails favoured lower rainfall plots" and "Highest mite/ springtail ratios were found in habitats that are associated with high rainfall". (8.3.4)
Taking the kit to Todmorden
Present
This is what home soil lab looks like..
Let sit 1-3 days to allow the nematodes to crawl out of the soil. Make sure the sample stays in contact with the water - do not let the dish become dry. Covering the dish with plastic wrap or foil will help prevent drying. This tells us something about nematodes - that they cannot exist outside water. Except when they make cysts, which withstand all sorts of conditions.