Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer?

EduRev

All Courses

Explore Courses UPSC Exam UPSC Test Series Free Notes EduRev Infinity

Open App

UPSC Exam > UPSC Questions > Which of the following can be the possible c...

Which of the following can be the possible causes of Algal Bloom?

Agricultural Runoff

Discharge of untreated Sewage

Discharge of untreated Industrial Effluents

Blockage in the flow of rivers

Select the correct answer using the code given below:

a)
1, 2 and 3 only
b)
2, 3 and 4 only
c)
1, 2 and 4 only
d)
1, 2, 3 and 4

Correct answer is option 'D'. Can you explain this answer?

Join for Free

Join for Free

Most Upvoted Answer

Which of the following can be the possible causes of Algal Bloom? A...

Option d is the correct answer.

Option 1 is correct: Agricultural Runoff contains a high amount of nutrients like nitrogen and phosphorus due to increased use of fertilizers, especially nitrogen rich urea in modern agriculture. On reaching water bodies these nutrients stimulate the phytoplanktons in water such as blue-green bacteria, etc causing algal blooms in an unnatural amount, due to unnatural enhanced levels of plant growing nutrients in water.
Option 2 is correct: Discharge of untreated Sewage causes addition of organic wastes and pathogens in water bodies. These organic wastes act like manure and enhance nutrients in water bodies to unnatural levels, thus causing algal blooms.
Option 3 is correct: Discharge of untreated Industrial Effluents also results in an unnatural concentration of various chemicals in water bodies, some of these directly promote plant growth (nitrogen, phosphorus, etc), while others such as lead, mercury, etc cause death of aquatic organisms, whose decaying organic matter further acts as manure enriching nutrients of the water body leading to algal blooms.
Option 4 is correct: Algal blooms occur in water bodies that are stagnant, as there is no removal of enhanced levels of nutrients and no disturbance leading to unchecked proliferation of the algae. So, blockage of the flow of water, mostly due to human interventions such as the creation of dams, or diversion of natural waters for artificial projects leaving behind stranded lakes and blockage of river courses due to deposition of eroded soil (due to land use changes) helps in creating algal blooms.
Knowledge Base:
- Algal bloom is an unchecked proliferation/ growth of algae (green, blue-green, cyanobacteria, etc) in a water body in an unnatural amount leading to disbalance in that aquatic ecosystem and death of biodiversity of that water body. This is due to:
  - Decreased sunlight penetration. Algae cover the surface of the water body, causing the death of other oxygen-producing vegetation and other aquatic organisms.
  - Dead and decaying organic matter further adds nutrients to the water body fuelling more algal growth while also reducing oxygen availability, killing more organisms. This cycle repeats, till most of the water body becomes lifeless and loses its biodiversity.
  - Other factors influencing algal blooms are: sunlight, temperature, climate change, and turbidity.

Answered by Notes Wala · View profile

View all answers Start learning for free

Explore Courses for UPSC exam

Similar UPSC Doubts

Which of the following contribute in the eutrophication? Excessive use of fertilisers Untreated sewage Detergents containing phosphorous Discharge of industrial waste Select the correct answer using the code given below.

View answer

Which of the following are non-point sources of pollution in rivers? Surface drains carrying municipal sewage Run-off from agricultural fields Dumping of un-burnt/half-burnt dead bodies Dhobi ghats Effluents from industries Select the correct answer using the code given below.

View answer

Which of the following activitie(s) is/are responsible for the decrement in the economic output from inland fishery?1. Discharge of untreated effluents from the industrial units and urban silage which destroy the fish.2. Construction of dams prevents the free migration of fish to their usual breeding and feeding grounds.3. Deforestation and frequent flooding due to poor watershed management.Select the correct answer using the code given below

View answer

Consider the following processes:1. Agricultural runoff2. Open Defecation3. Discharge of Industrial Effluents4. Floods5. Discharge of coolant from Nuclear reactorsWhich of the above given processes are responsible for water pollution?

View answer

Directions for the following 7 (seven) items: Read the following two passages and answer the items that follow each passage. Your answers to these items should be based on the passages only.Passage -1The law in many parts of the world increasingly restricts the discharge of agricultural slurry into watercourses. The simplest and often the most economically sound practice returns the material to the land as semisolid manure or as sprayed slurry. This dilutes its concentration in the environment to what might have occurred III a more primitive and sustainable type of agriculture and converts pollutant into fertilizer. Soil microorganisms decompose the organic components of sewage and slurry and most of the mineral nutrients become available to be absorbed again by the vegetation.The excess input of nutrients, both nitrogen and phosphorus - based, from agricultural runoff (and human sewag e) has caused many healthy oligotrophic lakes (low nutrient concentrations, low plant productivity with abundant water weeds, and clear water) to change to eutrophic condition where high nutrient inputs lead to high phytoplankton productivity (sometimes dominated by bloomforming toxic species). This makes the water turbid, eliminates large plants and, in the worst situations, leads to anoxia and fish kills; so called cultural eutrophication. Thus, important ecosystem services are lost, including the provisioning service of wild-caught fish and the cultural services associated with recreation.The process of cultural eutrophication of lakes has been understood for some time. But only recently did scientists notice huge dead zones in the oceans near river outlets, particularly those draining large catchment areas such as the Mississippi in North America and the Yangtze in China. The nutrient-enriched water flows through streams, rivers and lakes, and eventually to the estuary and ocean where the ecological impact may be huge, killing virtually all invertebrates and fish in areas up to 70,000 km2 in extent. More than 150 sea areas worldwide are now regularly starved of oxygen as a result of decomposition of algal blooms, fuelled particularly by nitrogen from agricultural runoff of fertilizers and sewage from large cities. Oceanic dead zones are typically associated withindustrialized nations and usually lie off- countries that subsidize their agriculture, encouraging farmers to increase productivity and use more fertilizer.Q.According to the passage, why should the discharge of agricultural slurry into watercourses be restricted?1. Losing nutrients in this way is not a good practice economically.2. Watercourses do not contain the microorganisms that can decompose organic components of agricultural slurry.3. The discharge may lead to the eutrophication of water bodies.

View answer

Top Courses for UPSCView all

Current Affairs & Hindu Analysis: Daily, Weekly & Monthly

Top Courses for UPSC

View all

Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer?

Share with a Friend

Answer this doubt

Question Description
Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? for UPSC 2025 is part of UPSC preparation. The Question and answers have been prepared according to the UPSC exam syllabus. Information about Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for UPSC 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer?.

Solutions for Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for UPSC. Download more important topics, notes, lectures and mock test series for UPSC Exam by signing up for free.

Here you can find the meaning of Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer?, a detailed solution for Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice Which of the following can be the possible causes of Algal Bloom? Agricultural Runoff Discharge of untreated Sewage Discharge of untreated Industrial Effluents Blockage in the flow of rivers Select the correct answer using the code given below:a)1, 2 and 3 onlyb)2, 3 and 4 onlyc)1, 2 and 4 onlyd)1, 2, 3 and 4Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice UPSC tests.

Explore Courses for UPSC exam