A linear network of links consisting of living organisms in a food web that begins with the producers is a food chain. A food chain extends up to apex predator species. Moreover, a food chain intertwines with the food web, which is a vast network. Normally food chains begin with the plants that are producers except for the Detritus Food chain. This is because it begins with the dead organic matter. We will learn about what are detritus organisms, what is the detritus food chain, how it begins and many more things about the detritus food chain in this article.
As we know that decomposers feed on the dead and decaying matter. Thus, the dead organic substances in nature are degraded with the help of decomposers. These decomposers are microorganisms. The decomposers are also known as detritivores because they feed on detritus. Therefore, the food chain that begins with dead organic matter is known as a detritus food chain. Detritivores are further consumed by predators. Normally, in a detritus food chain, the excreted products by one organism are utilized by another organism.
Detritus in biology is defined as particulate dead organic matter and it does not include dissolved organic matter. This is why it often includes the bodies or fragments of bodies of dead organisms and faecal matter. A detritus plays a host to several communities of microbes. These microbes colonize and decompose the organic material it’s feeding on. It can also be said that they remineralize it.
Detritus food chain is found in many different locations. That is, it is not restricted to a single type of habitat. It could be aquatic or terrestrial. In the terrestrial ecosystem, it is present in dead decaying leaves or leaf litter and other soil organic matter (organic matter mixed with the soil). In an aquatic ecosystem, it is found in organic matter suspended in the water bodies like lakes, ponds, rivers, or by the bottom of the water body. In case of the floor of the sea bed, it is covered by marine snow - a continuous shower of organic detritus falling from the upper layers of the water column. Marine snow acts as a biological pump.
The dominance of detritus food chains in various habitats also indicates that the ecosystems of the detritus food chain are not necessarily dependent on solar energy.
This kind of food chain has a continuous flow of energy as opposed to other types of food chains. For example- in a grazing food chain, distinct transfer of energy takes place in between the various trophic levels.
Energy obtained for this type of food chain is from the dead and decomposed matter called detritus. Therefore, autotrophs do not directly enter the detritus food chain, neither do they act as producers.
Wastage is minimum in this kind of food chain because the detritivores utilize the detritus to its fullest to acquire energy. It is a very efficient food chain.
Detritus food chain replenishes and recycles the nutrients and returns them back to nature for the autotrophs to process again and begin other food chains.
It includes subsoil species of all kinds which may be macroscopic or microscopic.
Detritus food chain has a much larger energy flow in the terrestrial ecosystem when compared to the other food chains of the food web.
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1. Detritus Food Chain Begins with What?
Ans: In a detritus food chain, energy comes from organic matter that is generated in trophic levels of the terrestrial food chain. It begins with detritus that includes dead bodies of animals or fallen leaves, leaf debris. These are eaten by decomposers or the detritivores. These detritivores are finally consumed by their predators in the food chain. So, it is usually smaller as compared to the terrestrial food chain. Primary consumers in a detritus food chain are detritivores like protozoans, bacteria, fungi, etc. These organisms feed upon the detritus saprophytically. Therefore, the detritus food chain begins with the dead organic matter and not producers or autotrophs, unlike terrestrial food chains.
2. Who are the Primary Consumers in Detritus Food Chains?
Ans: Detritus food chain is the type of food chain in which the detritus is utilized to a maximum level. Therefore, there is minimum wastage of organic material. Thus, in a detritus food chain, the primary source of energy is dead organic matter, that includes leaf debris, plant parts and dead animals. Bacteria are the kind of organism found everywhere and in every habitat. They thrive in all sorts of climatic conditions, mostly and feed on the decaying matter. Thus, the detritus food chain begins with bacteria. Detritivores are primary consumers of the detritus food chain. And saprophytes like bacteria, fungi, protozoans are the primary detritivores.
3. Give Examples of the Detritus Food Chain.
Ans: When the leaves of a red mangrove tree fall into a shallow water body, hardly 5% of the leaves are eaten by phytophagous insects who feed directly on them before they fall. The rest of the smaller parts of leaves or plant parts are eaten by smaller organisms like insect larvae, copepods, etc. Later, these small organisms are consumed by carnivorous fishes. And, finally, the small carnivorous fishes are eaten by big fishes or fish-eating birds like sea eagles, gannets, etc.
Next example is the consumption of dead organic waste by microscopic organisms like bacteria or fungi. These microscopic organisms are later consumed by other detritivore organisms like snails, earthworms, etc.