Recents in Beach

Describe the life forms of aquatic ecosystem found in different zones with suitable examples and diagrams.

i) Biota of Littoral Zone: This zone is the shore region of the marine ecosystems and is subject to violence of waves and tides, fluctuation of water level and variability of temperature, light, salinity and moisture. In common language supra littoral zone is termed as a beach. There are few species of plants present in this zone.

Common animals found here are snails, clams, barnacles, crustaceans, annelids, sea anemones and sea urchin. The animals here exhibit zonation with respect to tides. Animals more resistant to desiccation usually occurring at higher levels than those that are less resistant.

ii) Biota of the Neritic Oceanic Zone: This relatively shallow, coastal zone is rich in species and high in productivity owing to factors such as penetration of light to considerable depths and high concentrations of nutrients.

The most productive phytoplanktons are the dinoflagellates and diatoms, though red, brown and green algae attached to the bottom in the shallow regions may be significant. The zooplanktons are usually similar to those of the pelagic zone though some purely open-sea species are replaced by neritic species.

Almost all commercial species of fish as well as whales, seals, seaotters, sea snakes and large squids are found here. Fishes are numerous and include several shark species as well as sea trout and salmon.

A wide variety of animals among which are clams, shrimps, snails, lobsters, crabs, sea cucumber, starfish, brittle stars, anemones, sponges, bryozoa, annelids and foraminifera and exhibits more diversity than those of the deeper waters.

iii) Biota of Pelagic Zone: Pelagic region constitutes 90 per cent of the total ocean surface and is less rich in species and numbers of organisms than the two regions discussed before.

The most abundant pelagic phytoplanktons are still the dinoflagellates and diatoms which are the chief photosynthetic feeders, others are carnivores. Sea cucumbers and sea urchins crawl on the floor eating detritus and bacteria and serve as food for the carnivorous brittle stars and crabs

iv) Biota of Benthic Zone : It forms the floor of the ocean. Organisms here are hetrotrophic Rooted animals are sea lilies, sea fan, sponges etc. Snails and clams remain embedded in mud while starfish, sea cucumbers and sea urchins move on its surface.

Subcribe on Youtube - IGNOU SERVICE

For PDF copy of Solved Assignment

WhatsApp Us - 9113311883(Paid)

Post a Comment

1 Comments

Please do not enter any Spam link in the comment box

close