Each step represents a trophic level and the complex food chains within a community interconnect and is known as a food web. The final trophic level that connects consumer to producer is that of the decomposers. They live on dead plant and animal material and the waste products excreted by living things. The nutritional activity of these replenish nutrients that are essential ingredients for primary production. This contains an enormous amount of energy and nutrients.
Saprophytes decompose detritus completing the cycle.
The numerical relationship is called the pyramid of numbers. The energy pyramid is the energy distribution at each trophic level as it passes from producers through the consumers. Most scavengers consume detritus rather than flesh and deep sea animals can feed on both. If mortality is greater, then the population decreases. These favorable conditions depend on high concentration of nutrient rich water, rapid cycling of materials by decomposers, high numbers or rapid turnover of producer organisms Light nutrients including nitrate, phosphate, silicon, potassium, magnesium, copper, iron.