Consider the following statements with respect to the eutrophication o...
- Eutrophication is the natural aging of a lake by nutrient enrichment of its water. Hence statement 1 is not correct.
- In a young lake, the water is cold and clear, supporting little life. With time, streams draining into the lake introduce nutrients such as nitrogen and phosphorus, which encourage the growth of aquatic organisms.
- As the lake’s fertility increases, plant and animal life burgeons, and organic remains begin to be deposited on the lake bottom.
- Over the centuries, as silt and organic debris pile up, the lake grows shallower and warmer, with warm-water organisms supplanting those that thrive in a cold environment.
- Marsh plants take root in the shallows and begin to fill in the original lake basin.
- Eventually, the lake gives way to large masses of floating plants (bog), finally converting into land.
- Depending on the climate, size of the lake, and other factors, the natural aging of a lake may span thousands of years.
- However, pollutants from man’s activities like effluents from industries and homes can radically accelerate the aging process. This phenomenon has been called Cultural or Accelerated Eutrophication.
- During the past century, lakes in many parts of the earth have been severely eutrophied by sewage and agricultural and industrial wastes.
- The prime contaminants are nitrates and phosphates, which act as plant nutrients. They overstimulate the growth of algae, causing unsightly scum and unpleasant odors, and robbing the water of dissolved oxygen vital to other aquatic life. Hence statement 2 is correct.
- At the same time, other pollutants flowing into a lake may poison whole populations of fish, whose decomposing remains further deplete the water’s dissolved oxygen content. In such a fashion, a lake can literally choke to death.
Consider the following statements with respect to the eutrophication o...
Statement Analysis:
1. Eutrophication is a manmade process and does not occur naturally:
Eutrophication is a natural process that can be accelerated by human activities. While lakes can naturally become eutrophic over time, human actions such as excessive nutrient runoff from agriculture, sewage discharge, and industrial activities can speed up this process significantly.
2. The prime contaminants for eutrophication are nitrates and phosphates:
Nitrates and phosphates are indeed the primary contaminants responsible for eutrophication. These nutrients stimulate the growth of algae and aquatic plants, leading to excessive plant growth, oxygen depletion, and ultimately, the degradation of water quality in lakes.
Correct Answer:
Option B - 2 only
In conclusion, while eutrophication can occur naturally, human activities play a significant role in accelerating this process. Additionally, nitrates and phosphates are the main contaminants responsible for eutrophication in lakes.
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