Question

Microscopic aquatic organisms lacking locomotor ability and drifting with water current are-
A) Pleuston
B) Nekton
C) Plankton
D) Seston

Answer 1

They are all organisms found in water bodies and help in maintaining aquatic ecosystems. Organisms that don’t have locomotory organs move with the help of water currents while many of them have locomotory organs.

Complete answer:
Now let us look into the given explanation to get the correct answer:
Those organisms that dwell suspended in the water column and lack the locomotory ability to swim against regular ocean currents are known as planktons. Phytoplankton, zooplankton, and bacteria are among them.

Nektons are animals that travel through the water column but have stronger swimming ability and can swim against the current or through stormy water. Fish, squid, octopus, sharks, and marine animals are examples of nekton, which are heterotrophic and come in a wide range of sizes. Most nekton is pelagic, meaning they reside in the water column, while others are demersal, meaning they reside near the bottom. Nekton is mainly pelagic, meaning they live in the water column, but some are demersal, meaning they live at the bottom, and they can be found in both coastal and oceanic environments.

Sestons are microscopic particles that move across water and include both live and nonliving creatures (plankton and nekton) (such as plant debris or suspended soil particles). Pistons are creatures that live in the thin surface layer that exists at a body of water's air-water interface. Glaucus, Sargasso, and other molluscs are examples.

Thus the correct answer is option ‘C’ planktons.

Note: Animals that live on the seafloor are called benthos. The majority of these animals are classified as invertebrates since they lack a backbone. Sea anemones, sponges, corals, sea stars, sea urchins, worms, bivalves, crabs, and a variety of other invertebrates are common benthic invertebrates.