Detritus

The remains of decaying plants or animals, or their tissue parts, and feces gradually lose their form due to physical processes and the action of decomposers, including grazers, bacteria, and fungi.

Micro- and macro-organisms that feed on it rapidly consume and absorb materials such as proteins, lipids, and sugars that are low in molecular weight, while other compounds such as complex carbohydrates are decomposed more slowly.

[citation needed] The decomposing microorganisms degrade the organic materials so as to gain the resources they require for their survival and reproduction.

[2] Accordingly, simultaneous to microorganisms' decomposition of the materials of dead plants and animals is their assimilation of decomposed compounds to construct more of their biomass (i.e., to grow their own bodies).

In ecosystems on land, detritus is deposited on the surface of the ground, taking forms such as the humic soil beneath a layer of fallen leaves.

The exact composition of this detritus varies based on location and time of year, as it is very closely tied to primary production.

Many organisms, including sea slugs and serpent's starfish, scoop up the detritus which has settled on the water bed.

In contrast, from the point of view of organisms using photosynthesis such as plants and plankton, detritus reduces the transparency of the water and gets in the way of this process.

Given that these organisms also require a supply of nutrient salts, in other words fertilizer, for photosynthesis, their relationship with detritus is a complex one.

Investigating the level of inorganic salts in sea ecosystems shows that unless there is an especially large supply, the quantity increases from winter to spring—but is normally extremely low in summer.

The thinking is that organisms like plants grow quickly in warm periods and thus the quantity of inorganic salts is not enough to keep up with the demand.

In other words, during winter, plant-like organisms are inactive and collect fertilizer, but if the temperature rises to some extent they will use this up in a very short period.

When animals such as fish are kept in an aquarium, they produce substances such as excreta, mucus, and dead skin cast off during moulting.

Modern sealife aquariums often use the Berlin Method, which employs a piece of equipment called a protein skimmer, which produces air bubbles which the detritus adheres to and forces it outside the tank before it decomposes and also a highly porous type of natural rock called live rock where many benthos and bacteria live (hermatype which has been dead for some time is often used), which causes the detritus-feeding benthos and micro-organisms to undergo a detritus cycle.