Zooplankton are small animals in the planktonic community. These microorganisms are heterotrophic aquatic organisms. In Greek, "zoo" comes from "anima" and "plankton", which means wanderer, drifter, or wanderer. Even though some of them are larger, they are typically microscopic.
Biochemically, zooplankton are heterotrophic planktonic organisms ranging in size from microscopic organisms to large creatures. These organisms drift in aquatic ecosystems and are ecologically significant drifting organisms. The presence of these small animals in the water column of all water bodies is crucial to maintaining the food chain. Although they are rare in rivers and streams, they can be found in lakes, ponds, and oceans.
A few millimetres to a few microns is the size of these organisms (1 micron is 1/10000 of a millimetre).
The main transport mechanism for zooplankton species is ambient water currents. In some cases, locomotion is used to either avoid predators or increase the rate at which prey is encountered.
There are two ways to group zooplankton: by size and by developmental stage.
Zooplankton Classification by Size
Picoplankton: Zooplankton that is no larger than 2 micrometres.
Nanoplankton: This category consists of zooplankton that is between 2 and 20 micrometres in size
Microplankton: A form of zooplankton with a size range of 20-200 microns.
Mesoplankton: This category includes zooplankton between 0.2 and 20 millimetres in size.
Macroplankton: Animals between 20 and 200 millimetres in size.
Megaplankton: Populations of zooplankton that measure over 200 millimetres in size, or about 8 inches in length.
Zooplankton Classification Based on Their Developmental Stages
Meroplankton: Meroplankton is zooplankton when it is in larval form. Over time, they metamorphose into molluscs, corals, fishes, insects, echinoderms, and crustaceans.
Holoplankton: Zooplanktons that remain planktonic throughout their lives. Pteropods, larvaceans, copepods, chaetognaths, and siphonophores are examples of these organisms.
Distribution of Zooplankton
Radiolarians: As well as radiolarians, there are radiozoa. Protozoans that produce mineral skeletons made of silica are small, 0.1-0.2 mm in diameter. Globally, this type of zooplankton is found in all oceans. Ocean bottoms often contain the skeletal remains of these organisms.
Dinoflagellates: In the distribution of zooplankton, these are very few in number. Because they are photosynthetic or ingest other species, they are considered mixotrophic species. Dinoflagellates account for a significant proportion of marine eukaryotes and are essential to coral reef health.
Crustaceans: Organisms of this type are arthropods. Barnacles, crabs, krill, and shrimp are among them. A significant part of the food chain they are a variety of sizes. The zooplanktonic species krill and copepods are especially important among crustaceans.
Molluscs: A wide variety of organisms makes up the molluscs. Octopuses, squids, sea snails, and sea slugs are some of the species found in these waters. The larvae stage of these organisms is usually zooplanktonic.
Chordates:An animal that has a notochord, pharyngeal slits, a hollow nerve chord on the dorsal side, and a post-anal tail is called a chordate. This distribution of zooplankton has a large variety of forms and functions.
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Aquatic sowbug or water louse
Portuguese man o’ war
Blue button (Porpita porpita)
Common rough woodlouse
Pacific sea nettle
Flying spaghetti monster (Bathyphysa conifer)
What are the Benefits of Zooplankton?
Zooplankton plays an important role in the food web of water bodies due to their position in the food chain. These factors can have a significant impact on the quality of the water, fish production, algal densities, and nutrient and contamination cycling.
Biomonitoring programs frequently include zooplankton species due to their sensitivity to environmental change. Furthermore, some zooplankton species, such as Mysis, have been intentionally introduced to lakes to increase fish production.
Algal blooms may be controlled by increasing zooplankton grazing because zooplankton feed on algae. Biomanipulation is the process of doing this.
Normally this is accomplished by reducing predation on the zooplankton diagram; their predators, such as planktivorous fish, are either removed directly, or a fish predator, such as a pike, is added. Grazing by zooplankton can prevent eutrophication caused by algal blooms in water bodies.
Difference Between Zooplankton and Phytoplankton