Copepods

Pronunciation

How to pronounce Copepoda: //kəʊˈpɛpədə//

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Summary

Copepods are small, diverse crustaceans that are vital contributors to aquatic ecosystems, serving as a significant food source within the food web and as biodiversity indicators across a range of water habitats.

Physical Characteristics

Usually 1-5 mm in length, cylindrical and segmented body, transparent exoskeleton, with one median compound eye and two pairs of antennae; free-living copepods typically have a cylindrical body and a rounded head.

Identification Tips

Look for the teardrop-shaped body andlarge antennae; the presence of a single median eye is characteristic, and some species also have specialized adaptations such as telescope eyes.

Habitat

Copepods can be found in various aquatic habitats, including freshwater, saltwater, wetlands, vernal pools, subterranean caves, the water-filled recesses of plants, and leaf litter.

Distribution

Copepods are nearly ubiquitous, found in every oceanic and freshwater habitat; about 2,800 species are freshwater species.

Diet

Copepods primarily feed on phytoplankton, detritus, and some species are predaceous, feeding on smaller copepods and other zooplankton. Parasitic copepods may feed on host organisms.

Life Cycle

Copepods undergo a life cycle that includes an egg stage, nauplius larva, and multiple molts before reaching the adult form, which may take from a week to a year depending on environmental conditions.

Reproduction

During mating, males grip females with their antennae and transfer sperm. Eggs can be laid directly into water or enclosed in a sac until hatching, with some capable of enduring dormancy during unfavorable conditions.

Predators

Copepods are preyed upon by small fish, larger crustaceans such as krill, and various aquatic animals.

Ecosystem Role

Copepods play a crucial role in aquatic ecosystems as primary consumers, converting phytoplankton into energy for higher trophic levels and as key contributors to the carbon cycle.

Economic Impact

Copepods are important in marine aquaculture and aquarium hobbies as a food source for other marine organisms. They can also affect water supply management due to their role in health-related issues.

Cultural Significance

Copepods have appeared in media, such as the Nickelodeon television series SpongeBob SquarePants, featured as the character Sheldon J. Plankton.

Health Concerns

Copepods can be vectors for parasites such as Dracunculus medinensis (Guinea worm) and are associated with the transmission of cholera in untreated water supplies.

Collecting Methods

• Net sampling in freshwater or marine environments
• Using traps or specific collection equipment in targeted habitats

Preservation Methods

• Preserving in ethanol for morphological studies
• Freezing for molecular research

Evolution

Copepods have a long evolutionary history dating back to the late Carboniferous period, with transitions to parasitism occurring multiple times independently.

Similar Taxa

• Amphipoda
• Barnacles (Cirripedia)
• Branchiopoda

Misconceptions

Copepods were once misidentified as separate species due to their distinct larval form (nauplius) or as zoophytes/insects shortly after discovery.

Tags

• Copepoda
• Crustaceans
• Aquatic Ecology
• Biodiversity
• Food Web