Calanoida

Calanoida is an order of copepods, a group of small crustaceans found in marine and freshwater environments. They are a key component of the aquatic food web, serving as a primary food source for many fish species and other marine organisms.

Description

Calanoids are characterized by their elongated bodies and long antennae, which they use for swimming. They typically have a single eye and a segmented body that includes a head, thorax, and abdomen. The thorax is often fused with the head, forming a cephalothorax. Calanoids are distinguished from other copepods by their jointed first antennae, which are often as long as or longer than their bodies.

Habitat and Distribution

Calanoida are found in a wide range of aquatic environments, from the open ocean to freshwater lakes and rivers. They are particularly abundant in the plankton of the world's oceans, where they play a crucial role in the marine food web. Calanoids are also found in estuarine and brackish waters.

Ecological Role

Calanoids are primarily herbivorous, feeding on phytoplankton and other small particles suspended in the water. They use their antennae and mouthparts to create feeding currents that draw food particles towards them. Some species are omnivorous or even carnivorous, preying on smaller zooplankton.

As a major component of the zooplankton community, calanoids are an essential link in the transfer of energy from primary producers (phytoplankton) to higher trophic levels, including fish, birds, and marine mammals. They are also important in the cycling of nutrients within aquatic ecosystems.

Reproduction

Calanoids reproduce sexually, with most species exhibiting separate sexes. Females typically carry eggs in a sac attached to their bodies until they hatch into nauplius larvae. These larvae undergo several molts before reaching adulthood.

Research and Importance

Calanoids are studied extensively in marine biology and ecology due to their abundance and ecological significance. They are used as indicators of environmental change and are important in studies of oceanic carbon cycling and climate change.

Also see

• Copepoda
• Plankton
• Marine food web
• Phytoplankton
• Zooplankton