Soil Food web – Predator-Prey Protists Bacteria Fungi Microarthropods are some of the main components in soil microbiology. Below is a predator/Prey food/eating chart. Arrows indicate who is eating what. Some of the food materials are organic (meaning they contain some carbon), while other organisms are eating inorganic materials (like NO3, NO and etc…)
The tangled web produces enough fixed nitrogen to support a productive ecosystem for people to live. If soil is treaded accordingly, with these animals in mind, it can produce more than applications of synthetic fertilizers. See the link below for calculations and comparisons:
If you are interested and have access to a microscope, here is a link for you. How to prepare your soil samples to see all of your soil’s microbiology:
Bacteria constitute a large domain of prokaryotic microorganisms. Typically a few micrometers in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most habitats on the planet, growing in soil, acidic hot springs and harsh conditions.
Bacteria are vital in recycling nutrients, with many steps in nutrient cycles depending on these organisms, such as the fixation of nitrogen from the atmosphere and putrefaction. In the biological communities surrounding hydrothermal vents and cold seeps, bacteria provide the nutrients needed to sustain life by converting dissolved compounds such as hydrogen sulphide (H2S)and methane (CH4).
Below are some videos of H2S eating bacteria. The surrounding green strands are Cyanobacteria. And some of the Cyanobacteria is being eaten.
Fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts, molds, and mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. Chitin is the main component of the cell walls of fungi, the exoskeletons of arthropods such as crustaceans and insects.
Hypha is a long, branching filamentous structure of a fungus. Collectively called a mycelium. Below is a picture of hypha (400X). You can see the cell walls forming uniform lengths of cells. A general rule of thumb in determining if a fungal hypha is constructive or pathogenic; if the color of the fungi is clear and less than 1 um in width, it is generally thought of as pathogenic (disease causing) . If the hypha is around 3 um and is brown in color, it is generally thought of as constructive or symbiotic.
Saprophytic fungi feed on dead plant and animal remains. Many are extremely beneficial, breaking down this organic material into humus, minerals and nutrients that can be utilized by plants. Below are saprophoric fungi
Mycorrhizae Fungi is a symbiotic association between a fungus and the roots of a vascular plants. It’s generally mutualistic, but occasionally weakly pathogenic. Mycorrhizae Fungi needs a host to survive. In many cases, the host is trees and/or some plants. The tree gives sugars to the Mycorrhizae Fungi and in return the Mycorrhizae Fungi give minerals and/or water. When Mycorrhizae Fungi works with plants, it increases the nutrient take-up surface area. A common Mycorrhizae Fungi is Chanterelles, pictured below. It’s symbiotic with Oak Trees.
When trying to identify Mycorrhizae Fungi, they can be seen in the roots of plants/trees. See below the connection nodes between Mycorrhizae Fungi and tree roots. In this case the hyphae are still attached to the root nodes.
Ectomycorrhizas – (Considered in Late Plant Succession) can be found with a number of tree and shrub species, especially from the Pinaceae (pine tree family), Fagaceae (Beech tree family), Betulaceae (Nut bearing tree – alders, hazels and etc…), Salicaceae (willow tree family), Dipterocarpaceae (South Asian, African timber trees and Mallow family , Myrtaceae (guava and eucalyptus family), and Caesalpiniaceae (spiny trees, shrubs, or perennial herbs, including the genera Caesalpinia, Cassia, Ceratonia, Bauhinia; commonly included in the family Leguminosae) families.
Endomycorrhizas are variable and have been further classified as arbuscular, ericoid, arbutoid, monotropoid, and orchid mycorrhizas. Arbuscular mycorrhizae, or AM (formerly known as vesicular-arbuscular mycorrhizae, or VAM), are mycorrhizae whose hyphae enter into the plant cells, producing structures that are either balloon-like (vesicles) or dichotomously-branching invaginations (arbuscules). The fungal hyphae do not in fact penetrate the protoplast (i.e. the interior of the cell), but invaginate the cell membrane. The structure of the arbuscules greatly increases the contact surface area between the hypha and the cell cytoplasm to facilitate the transfer of nutrients between them.
Protozoa are a diverse group of unicellular eukaryotic organisms. Protozoa were regarded as the partner group of protists to protophyta, which have plant-like behavior like photosynthesis. Below are some videos showing Protozoan in action. All videos are taken at 400X magnification. Some have flagellum (whip like tales) and others have cilium (hairy edges). As a cysts (can go dormant in bad times), protozoa can survive harsh conditions, such as exposure to extreme temperatures or harmful chemicals, or long periods without access to nutrients, water, or oxygen for a period of time.
The nematodes or roundworms are traditionally regarded as the phylum Nematoda. Nematodes, (small worms) have successfully adapted to nearly every ecosystem from marine to fresh water, to soils, and from the Polar Regions to the tropics, as well as the highest to the lowest of elevations. The oral cavity is lined with cuticle, which is often strengthened with ridges or other structures, and, especially in carnivorous species, may bear a number of teeth. The mouth often includes a sharp stylet, which the animal can thrust into its prey. In some species, the stylet is hollow, and can be used to suck liquids from plants or animals. Below are some videos of nematodes feasting on algae.
Microarthropods are important components of the soil decomposer food web. Organic matter is a major influence on microarthropod abundance and diversity. Conservation practices that increase soil organic matter improve soil quality by supporting the development of the soil biotic community. Microarthropods and other small soil animals are visible (sometimes barely so) but miniscule; most require some level of magnification for identification. Many microarthropods, especially springtails and soil mites, are responsible for breaking down organic material into a form that bacteria can consume, and are fundamental to the creation of humus and the formation of soil.
The thin layer where soil and litter meet is especially crucial to this process. This layer of soil is the most biologically active; many species of microarthropods thrive only in the interface between soil and litter.
Below is a video of a fly larva. This is a Microarthropod. It’s a pest, but is really helps with the soil food web.