Soil Biology (Microfauna) - Terry Tollefson

here's our sample from the Beermen finals I'm now in the microscopy lab and I'm going to show you the technique that we use to examine this sample under a microscope so let's open up this sample and I have a little device here it's just simply a micropipette or a Pasteur pipette with a piece of tubing on it and I'm going to gently suck up if you like and I'll take another another sample okay like that and now I'm going to examine what I see under this stereoscopic microscope and I have a camera attachment mounted to it and so I'll record what I see so let's have a look at low magnification of first glimpse of our soil extract seems to show nothing more than soil particles in water however as we increase magnification we begin to see many tiny soil inhabitants the vast majority of the visible organisms in this extract are silver hair like worms collectively called nematodes to help you appreciate size relationships a graduated slide has been submerged in the extract this slide is in essence a very tiny glass ruler the distance between the small gradations is 1/10 of one millimeter in another extract I have located a rather large nematode which we can examine more closely nematodes have a variety of feeding habits this particular example is likely a plant parasite it makes a living by sucking the juices from plant roots using specially adapted mouth parts this individual seems less bothered than others by the lights of the camera but is determined to tie itself in a knot [Music] the rapid movement and transparent body of this next soil organism makes it difficult to see clearly this eight-legged creature is one of many species that belong to the mite family in the remaining sequences we are using a more powerful microscope at this magnification we are able to see single celled creatures called protozoa these fast-moving organisms are considerably smaller than even the small nematodes we see in this sample at higher magnification we turn our attention to examining internal structures rather than simply identifying individuals at first glance this nematode appears to be little more than a clear tube with a digestive tract suspended inside here is a closer look at a smaller nematode it moves by generating a wave of contractions along its body wall this produces a whip-like movement that propels them forward this particular individual appears to be stuck to a piece of organic debris preventing it from moving forward [Music] in this segment we see a very large somewhat transparent insect larva next to it a silvery mite and above it a comparatively small nematode this should serve to remind us of the huge diversity in size that exists among soil micro animals here's another look at a mite using a different light source it's comparatively rapid movement and its desire to hide behind organic debris makes it elusive to photograph here is a mite viewed at even higher magnification it gives us a clearer appreciation of mite anatomy the star of this short sequence is a rotifer rotifers commonly live in freshwater habitats but can also make a home in marine and soil environments rotifers feet by using tiny hairs called cilia to sweep particles of organic debris or single-celled organisms into their mouths this rotifer moves in an accordion like fashion planting it's sticky foot and pushing off from it these energetic creatures before you are called tardigrades also known as water bear these eight-legged animals are common to moist environments however they have a unique ability to survive in extreme drought and cold therefore we find tardigrades in our more drought prone grassland soils as well

Channel: undefined

Views: 79,632

Rating: 4.9205298 out of 5

Keywords: Soil, Biology, Nematodes, Mites, Rotifers, Tardigrades

Id: VuHznslr8aI

Length: 5min 35sec (335 seconds)

Published: Mon Sep 17 2007

Reddit Comments

[u/SamSlate]

PSA: there are many pipettes that do not require you to suck on a hose.

[u/nolasito]

This is a video I found of microscope videos from a soil sample. It's so crazy that permaculture exists even down to the minute level!

[u/aminimalvirus]

Very cool

[u/kalebshadeslayer]

You would probably enjoy Journey to the microcosmos. https://www.youtube.com/channel/UCBbnbBWJtwsf0jLGUwX5Q3g

[u/DavidoftheDoell]

Cool, but also gross