Consider the following statements regarding an aquatic ecosystem: Both...
The correct answer is option 'D' - 2 and 3 only. Let's discuss each statement in detail:
1) Both photosynthesis and respiration activities take place in aphotic zone:
- The aphotic zone refers to the portion of the water column in an aquatic ecosystem that receives little to no sunlight. In this zone, photosynthesis cannot occur as there is insufficient light. Photosynthesis is the process by which plants and some bacteria convert sunlight into energy, using carbon dioxide and water. Therefore, photosynthesis does not take place in the aphotic zone.
- However, respiration, which is the process by which organisms convert organic compounds into energy, does occur in the aphotic zone. Organisms in the aphotic zone rely on organic matter that settles from the surface or is brought in by currents. They consume this organic matter and undergo respiration to release energy.
2) Neuston are organisms which live at the air-water interface such as floating plants:
- Neuston refers to the organisms that live at the air-water interface, which is the boundary between the surface of the water and the atmosphere. These organisms are adapted to live in this specific habitat and can include floating plants, insects, and microorganisms, among others. Neuston organisms take advantage of the resources available at the air-water interface, such as sunlight and oxygen.
3) The limnetic zone is dominated by both phytoplankton and zooplankton:
- The limnetic zone is the open water area in a freshwater ecosystem that is well-lit and extends beyond the littoral zone. It is the area where light can penetrate, allowing photosynthesis to occur. This zone is dominated by phytoplankton, which are microscopic photosynthetic organisms that float freely in the water column and are the primary producers in the aquatic food chain. Phytoplankton are the foundation of the food web and are consumed by zooplankton, which are small, floating animals that feed on the phytoplankton. Therefore, the limnetic zone is indeed dominated by both phytoplankton and zooplankton.
In summary, the correct statements are:
- Neuston are organisms which live at the air-water interface such as floating plants.
- The limnetic zone is dominated by both phytoplankton and zooplankton.
Consider the following statements regarding an aquatic ecosystem: Both...
- The topmost zone near the shore of a lake or pond is the littoral zone. This zone is the warmest since it is shallow and can absorb more of the Sun's heat. It sustains a fairly diverse community which can include several species of algae (like diatoms), rooted and floating aquatic plants, grazing snails, clams, insects, crustaceans, fishes, and amphibians.
- The near-surface open water surrounded by the littoral zone is the limnetic zone. The limnetic zone is well-lighted (like the littoral zone) and is dominated by plankton both phytoplankton and zooplankton. Hence statement 3 is correct.
- The deep-water part of the lake or pond is called the profundal zone. This zone is much colder and dense than the other two. Little light penetrates all the way through the limnetic zone into the profundal zone.
- Only respiration activity takes place in this zone. Hence statement 1 is not correct.
- Also known as aphotic zone.
- The fauna are heterotrophs, meaning that they eat dead organisms and use oxygen for cellular respiration.
- Nektons are animals which are swimmer.
- They are relatively large and powerful as they have to overcome the water currents.
- Floating plants are called as neuston. These are unattached organisms which live at the air water interface. Hence statement 2 is correct
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