Down Deep
Looking down Overview Surface Just Beneath Going Down
Worms
The main worms going verticaly down are those called 'Anecic' Their vertical burrows are more permanent, providing routes for other creatures
The most famous is the common earthworm Lumbricus terrestris . Their role as tunnel diggers is vital to many of those creatures we’ve just described. More on identifying worms
Sringtails getting whiter and blind as we go deeper, because they live a long way from light...
More Onychiuridae (Springtails)
Onychurids & Microbial Fungi - see 'bees of the soil'
As they move they accidentally carry fungal spores, helping fungi spread to maintain mycorrhizal realtions.
None of the main soil creatures are 'bugs' in the proper sense of the word - ie belonging to the Order Hemiptera of Insects (like aphids and cicadas). The main arthropods in the soil - mites and springtails are not insects (although there is a debate among taxonomists as to how collembolans are related to insects). There very few insects that spend their whole lives underground. This is possibly because insects evolved after mites and springtails, as a way of escaping the soil - by taking to the wing. All insects have wings. Their classification is baesd on their wing patterns. So Hemiptera refers to 'half' (Hemi) wings (Ptera). However wings are no use underground. So did they evolve from other soil arthropods and take flight? Springtails would be most likely ancestors. (New light on oldest insect) More on all this in Birth of the Earth
Oribatids Worms mangle organic matter but it is the myriad of mites that break down organic matter into v small parcels for fungi and bacteria to act on. The 'mesofauna' break down the leaves – springtails prising apart leaves. But is mainly oribatids that breakdown the big carbon molucules like chitin and lignin. Thier bodies are full of microorganism that do the chemical breakdown in the protection of their bodies. The process of 'humification' - turning dead matter into humus, involves many different soil animals.
This absolutely vital process for all life occured AFTER the early development of soils and the evolution of trees. How else can you explain th epresence of 'fossil fuels' like coal and oil? This vital process would have stopped their formation - as it has ever since.
EO Wilson said: The world is run by little creatures most people have not heard of; They are called 'oribatids' "
Fungi sprout mushrooms which come above ground so we see them at certain times. Fungi, alga and and bacteria work on broken down plant remains coming out of the mites/ worms, turning chemicals like Lignins and cellolose – hard bits, into simpler carbohydrates Humification is the name of the process that does this, turning leaves and other plant debris into
Certain mites feed on nematodes
Nematodes
The third main group of soil mesofauna, alongside springtails and mites, are nematode worms. Pretty boring looking - basically just a sheath covering the guts. See how Nematodes move. Some are directly parasitic on plants but many are bacterivores and fungivores not feeding directly on soil organic matter, but on the bacteria and fungi which have decomposed organic matter
Click to find out all about Nematodes
Bacteria
Bacteria are tiny, one-celled organisms about (1 µm). A teaspoon of decent soil 100 million - 1 billion bacteria. That is as much mass as two cows per acre. – a tonne.
Bacteria dot the surface of strands
Most are bacteria consume simple carbon compounds, such as root exudates and fresh plant litter, convertingl organic matter into forms useful to the rest of the organisms. Somes can break down pesticides and pollutants in soil. Decomposers prevent the loss of nutrients, such as nitrogen, from the rooting zone. Bacterial pathogens include Xymomonas and Erwinia species, and species of Agrobacterium that cause gall formation in plants. Chemoautotrophs obtain energy from compounds of nitrogen, sulfur, iron or hydrogen instead of from carbon compounds.Nitrogen fixing bacteria also live closely with roots. The bacteria invade root hairs and multiply making the nodules (below), where the bacteria convert free nitrogen into nitrates which is like a natural fertiliser for the plant.
Nitrogen-fixing bacteria evolved relatively late in soil's evolution - about 60mya. Soils started, with many bacteria involved, much earlier - around 400mya. See Birth of Earth