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Down Deeper

Worms

Ecological groups of wroms
The endogeic earthworms, like L. rubella, pull leaves down into burrows. In soil fauna terms they are like massive earth moving equipment. Earthworm eating plant stem Worms working a field, then themselves
Endogeic worm




Anecic worms
The ones that live deep down belong to the group Anecic, the most famous of which is the earthworm Lumbricus terrestris
Their role as tunnel diggers is vital to many of those creatures we’ve just described. More on identifying worms



Symphyla: SymphylaThese are related to centipedes, and are their 'living in the dark' cousin.  Have a look at a couple alive. They feed directly on plant roots, so can be a pest to crops

Insect larvae: 
Bibionid larvaBibionid adult
Bibionid larva above like many soil living insect larvae, with white coloured segmented body, and dark head. They turn into these 
Leather jackets can be a plague under lawns.
Leatherjacket
They develop into the familiar daddy long legs.
Daddy Longlegs
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 thier 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
When leaves fall..
Tree roots 

Protura
Proturans have virtually no distinguishing features. So much so they weren't discovered till the 20th century. they feed on organic matter released by decay. They are considered the earliest 6-legged creatures to evolve.




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 


Mites (Key for Mites)

Oribatids roll up
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 mainly oribatids

The process of 'humification' - turning dead matter into humus, involves many different soil animals. (Build this later)'
Predatory Mites

Another group of mites – Mesostigmata.Mesostigmtic miteClick to see one having a meal They have a long proboscis to
feed on nematodes…and yummy springtails (clip form my video). Perhaps they should become the 'Indicator of healthy soils'? Like all great predators - like hawks and buzzards, their presence means there must be prey about - indicating that there are a lot of soil 'bugs' about.  Like these..


Nematodes

NematodeThe 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 

Nematode feeding types
Click to find out all about Nematodes







Fungi
Mycorrhiza
The 'Rhizosphere dynamics' mentioned here indicates the roots and their relationship with bacteria (like nitrogen fixing bacteria - see below) and fungi - particularly Mycorrhiza fungi.   This term was first created over 130 years  ago - Glossary. These fungi are attached to the root and take sugars from roots for their own energy and return soluble nutrients in the soil; these will have come as part of the breakdown products of decomposers like oribatids (see below). This is a crucial part of the overall life cycle of the world/earth. It means trees can access mineral nutrients to be fed properly. The fungi also increase the surface area of roots to enable more transfer of chemicals in and out. More

Onychiuridae (Springtails)
Onychurid
have the capacity to carry spores of mycorrhizal fungi and mycorrhiza-helper bacteria on their tegument to the roots, so these soil springtails play a positive role in the establishment of plant-fungal symbioses and thus are beneficial to agriculture.[look at source] You could call them 'the bees' of the soil as an indicator of how important they are - and how, like bees, carry out a vital functions, quite accidentally. 

Some sorts of fungi consume nematodes by sticking the nematodes to their hyphae.

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

BacteriaMost 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.

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