User:Goobglorp/Planktivore

Planktivore Ecology
Plankton are among the lower trophic levels in food chains. Planktivores affect the food chain by altering plankton populations in various ways, a process known as the trophic cascade. The gizzard shad, again, plays this role. It consumes phytoplankton when it is small, zooplankton when it is larger, and other foods when it eliminates the zooplankton in the area. It incidentally controls the populations of other fish that depend on zooplankton, such as bluegil l (Lepomis macrochiris).

Other planktivores, such as mussels, play a vital role as ecosystem engineers as they biofiltrate, stabilize stream beds, and provide surface area for various benthic microorganisms. Varying species of these bivalves feed on all types of plankton, such as bacteria, algae, and other phytoplankton. They can also significantly alter the nutrient cycles of their aquatic ecosystem through their filter-feeding and subsequent excretion, while some species are even able to remove nitrogen in streams. However, as native mussel species provide many benefits to their habitats, increasing populations of invasive mussels have been deleterious.

For example, originally from the Ponto-Caspian region, the genus Dreissena has infiltrated the Great Lakes of North America and reduced native species in affected areas. The dreissenid species, Dreissena polymorpha, and Dreissena rostriformis bugensis (the zebra mussel and the quagga mussel, respectively), have colonized and impacted the natural ecosystem. Their presence has been correlated with altering the numbers of phytoplankton and zooplankton that inhabit the waterbodies due to their manipulation of nutrient cycling as they disperse large amount of inorganic nutrients. These mussels have also been indicated as a source of nutrient sinks due to their vast numbers and the containment of large amounts of phosphorus within their bodies.

Because planktivores, such as mussels, impact nutrient cycles, they are an essential part of the chemistry of aquatic systems as they can be highly beneficial and immensely impactful.