During an educational trip, a group of students visited a village having a beautiful lake. The students collected some plants samples and noticed that some villagers are washing clothes around the lake. They also observed that the dumping of waste material from houses into the lake at certain points.

After few years, the students happened to visit the same village again. They were shocked to find the green cover over the lake water which was unusable and badly stinking

Answer the following questions:
a) What is the name of green cover over lake water?
b) Why the lake water had developed bad small?
c) How this situation could have been avoided? Give your views.
d) What are the values associated with the above passage.

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Solution

Dear Student,

a). The green cover is nothing but the algal blooms that resulted due to the deposition of nutrient rich sewage.
b). The lake is smelling due to the death of the fishes and other aquatic organisms due to the lack of oxygen resulted out of eutrophication.
c). This situation could have been avoided by not dumping any waste into the water bodies.
d). The values denoted by the passage is people are ignorant and not caring towards the environment. The values shown by the children are inquisitiveness and awareness about the environment.

Regards,

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Similar questions

Q. In a village, farmers started cultivating crops all around a lake which was always filled with water. They added lot of materials W to the soil in their fields to increase the yield of crops. Soon they found that the whole surface of water in the lake was covered with a green layer made up of tiny organisms X. After some time, the fish present in the lake started dying in large numbers because they could not get sufficient Y due to a process Z which had occurred in lake water and drained out all the Y present in the water of lake.
(a) What do you think materials W are?
(b) Name (i) X, and (ii) Y.
(c) What is the process Z known as?
(d) What happens during the process Z which uses up all the Y present in lake water?
(e) What does this example tell us about the use of materials like W?

Read the passage and answer the following question.

In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilisers to their field in order to enhance the yield. Soon they discovered that, the water body was completely covered with green floating plants and fishes started dying in large numbers.

What is the cause for excessive growth of plants and death of fish in the lake?

Question 27
In a village in Karnataka, people started cultivating crops all around a lake which was always filled with water. They added fertilisers to their field in order to enhance the yield. Soon they discovered that the waterbody was completely covered with green floating plants and fishes started dying in large numbers.
Analyze the situation and give reasons for excessive growth of plants and death of fish in the lake.

Fishes died within a few days in a lake near a village. Following are the possible reasons for this:

(a) Lot of urea and phosphate fertilisers used in crops in the vicinity

(b) Spraying agricultural fields with degradable pesticides

(d) Phytoplankton population declined in the lake

What are the two main causes of fish mortality in the lake?

Q. A lake near a village suffered heavy mortally of fishes within a few days. Consider the following reasons for this.

(A) Lots of urea and phosphate fertilizers were used in the crops in the vicinity.

(B) The area was sprayed with DDT by an aircraft.

(D) Phytoplankton populations in the lake declined initially thereby greatly reducing photosynthesis.

Which two of the above were the main causes of fish mortality in the lake?

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