Trophic Levels

A trophic level is a hierarchical position that an organism occupies in an ecosystem. This is based on its source of energy. It is also known as feeding level. Trophic levels are represented through food chains, which show the flow of energy from one organism to another with the sun being the first source of energy.

Let's use as an example a food chain in a kelp forest. Here, the kelp would be the producer, which is eaten by blacksmith fish, who in turn is eaten by otters, who are then eaten by sharks.

The kelp is the producer and occupies the first trophic level. Being an autotroph, it is able to convert the Sun's energy into food for itself, and thus supporting the rest of the food chain.

Blacksmith fish would be the first consumers (herbivores), occupying the second trophic level. Otters are the second consumers (carnivore eating a herbivore), and are placed at the third trophic level. Finally, sharks are third consumers (carnivore eating a carnivore), and occupy the fourth trophic level. If we consider that when the shark dies it remains are broken down by bacteria, they would act as decomposers, placing them at a fifth trophic level.