Question

In a lake phytoplankton grow in abundance in

• A. littoral zone
• B. limnetic zone
• C. profundal zone
• D. benthic region

Answer 1

Answer: (B)

A typical lake has three distinct zones (limnetic, littoral and the benthic zone) of biological communities linked it to its physical structure. The littoral zone is the near shore area where sunlight penetrate all the way to the sediment and allows aquatic plants (macrophytes) to grow. The limnetic (or pelagic) zone is the open water area where light does not penetrate upto the bottom. Limnetic zone is the home of phytoplanktons (e.g., algae) and zooplanktons (e.g., crustaceans). Benthic zone (bottom of the lake) contains the flora and the fauna living at the bottom. Profundal zone refers to the deepest part of open water, which is relevant only in extremely deep lakes.