NEET BIOLOGY

Detailed explanation-1: -This zone is located under the thermocline where the sunlight does not penetrate the water. Again, the size of this zone depends on the age and water clarity of the pond or lake. The Profundal Zone typically has a low population of fish because of the lack of oxygen during many parts of the year.

Detailed explanation-2: -The profundal is often defined, as the deepest, vegetation-free, and muddy zone of the lacustrine benthal. The profundal zone is often part of the aphotic zone. Sediment in the profundal zone primarily comprises silt and mud.

Detailed explanation-3: -Oxygen Sinks in the Profundal Zone The primary sink of oxygen in the profundal zone is respiration of fish and bacteria. Many of these organisms feed upon the rain of detritus from the littoral zone. Respiration demand is particularly great in the benthic zone where bacteria are abundant in the sediment.

Detailed explanation-4: -Water near the surface of the lake– the epilimnion– is too warm for them, while water near the bottom–the hypolimnion– has too little oxygen.

Detailed explanation-5: -The profundal zone is chiefly inhabited by primary consumers that are either attached to or crawl along the sediments at the bottom of the lake. Such bottom-dwelling animals are called the benthos. The sediments underlying the profundal zone also support a large population of bacteria and fungi.