Zooplankton is the common name given to many small animal species found in freshwater and marine waters. The meaning of the word in Greek means "wandering animals". They float in water and do so specifically with currents. Most of these animals are so tiny that they are only visible under a microscope, although some species can reach longer lengths. They consist of adult microscopic beings and others in their larval stages of other organisms. Many of these animals are very similar, for example to shrimps and other crustaceans, as well as to worms, fish and jellyfish.
Zooplankton is a group of small animals that are located and inhabit near the surface in aquatic environments. They are not good swimmers, so they generally only move with the movement of the marine currents.
Some of its most relevant characteristics are the following:
Zooplankton can be divided into two different types of animals: holoplankton, which are those that spend their life cycle within the plankton; and meroplankton, which includes eggs, larvae and small fish that are in their early life stage. It is classified depending on its size, this way, we have the following classification:
According to their size, they can be classified into:
Phytoplankton obtains its energy and food directly from the sun through the process known as photosynthesis, and they do so in the same way as plants do. Zooplankton feeds on phytoplankton and small organisms such as diatoms and other protozoa and is then consumed by larger zooplankton that includes animals such as fish, but larger in size. Plankton is at the base of a complex aquatic food web. It is important to mention that zooplankton is located at the bottom of the oceanic food chain and outside the oceanic food net. That means that many creatures eat them.
Some of the most representative species are listed below:
The use and the different studies regarding zooplankton leaves us as a teaching that they have many good practical utilities for human being. For example, saline Artemia, which is a type of crustacean brachiopod belonging to zooplankton, which is used in aquaculture and aquatics to feed with one of the best diets, young and small fish. Franciscan Artemia is distributed in the form of cysts that have to be hatched in order to develop and be used as live food directly.
On the other hand, one of the most important features of zooplankton is that it contains krill. This is a type of malacostraceous crustacean that in addition to be the principal whales food, has been cultivated and consumed as human food in Japan. At present, it can be found as krill oil, which is very rich in omega-3 acids. It can also be used in various types of industrial applications as they are extracted chitin or chitosan that has multiple industrial applications, food and pharmaceutical.