Daily Static MCQs Quiz for UPSC, IAS, UPPSC/UPPCS, MPPSC. BPSC, RPSC & All State PSC Exams
Subject : Environment & Ecology
1. Increased Snow cover on a water body can lead to:
1. Sudden spurt in phytoplankton population which are not dependent on photosynthesis.
2. Improved oxygen exchange and nutrient recycling in the lake.
3. A condition of winterkill causing large scale death of fishes and organisms.
How many of the above statements is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (A)
Explanation: Phytoplankton float on top surface of water bodies and require sunlight to thrive. Ice cover will reduce their breeding grounds and population. The snow cover blocks exchange of nutrients and oxygen from the atmosphere, however the same may continue within the water stream. But it is worse than before. Snow cover of ice on water body can effectively cut off light, plunging the waters into darkness. Hence photosynthesis stops but respiration continues. Thus, in shallow lakes, oxygen gets depleted, and due to lack of oxygen there is large scale death of fishes and other organisms. This condition is known as winterkill. Hence, statement 3 is correct.
2. Consider the following statements regarding Black Carbon:
1. Black carbon is a component of fine particulate matter, formed through the incomplete combustion of fossil fuels, biofuel, and biomass.
2. In the tropics, black carbon in soils significantly contributes to the soil fertility.
3. Black carbon significantly increases the albedo when deposited on snow and ice.
How many of the above statements is/are correct?
(a) Only one
(b) Only two
(c) All three
(d) None
Answer: (B)
Explanation: Black carbon (BC) is a component of fine particulate matter. Black carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. Black carbon causes human morbidity and premature mortality. In climatology, black carbon is a climate forcing agent. Black carbon warms the Earth by absorbing sunlight and heating the atmosphere and by reducing albedo when deposited on snow and ice. In the tropics, black carbon in soils significantly contributes to fertility as it is able to absorb important plant nutrients. Hence, statement 3 is not correct.
3. Consider the following statements:
1. Cold water corals, in general, have greater amount of zooxanthellae than warm water corals and does not build reef-like structures.
2. Cold-water corals differ from warm water corals because the former does not contain symbiotic algae for photosynthesis and grow more slowly.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (B)
Explanation: Corals that inhabit the colder deep waters of continental shelves and offshore canyons, ranging from 50 to over 1000m depths lack zooxanthellae and may build reef-like structures or occur solitarily. Cold-water corals are different from their warm-water counterparts because they do not contain symbiotic algae for photosynthesis and grow more slowly. Cold-water corals obtain all their energy from organic matter and zooplankton, which they catch from the currents drifting past. Cold-water corals can be found over a wide range of latitudes, from tropical to Polar Regions, and from the shallow to the deep seas. Hence, statement 1 is not correct.
4. Lichen is a pioneer species. What do you understand by this statement?
(a) It contributes substantially to nutrient recycling in the ecosystem.
(b) It can live in inhospitable climatic conditions.
(c) It is generally one of the first species to colonize an ecosystem.
(d) It has the ability to form symbiotic relation with a large number of species.
Answer: (C)
Explanation: Lichens are typically the first organisms to colonize bare rock. They are therefore the pioneer species in primary succession. Many organisms require soil before they can colonize an area. Lichens that colonize bare rock secrete acids that break down the rock and start the soil-production process. Also, as lichens die, they provide some organic matter that also contributes to soil. Mosses can then colonize the thin soil; as mosses die, the soil thickens more allowing other hardy species to colonize. The process continues until a mature forest forms, sometimes centuries later. Hence, statement (c) is correct.
5. Consider the following statements regarding Arctic haze:
1. Arctic haze is the phenomenon of a visible reddish-brown springtime haze in the atmosphere at high latitudes in the Arctic.
2. The occurrence of Arctic haze has been mainly due to cosmic radiation from Van Allen Radiation belts.
Which of the above statements is/are correct?
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (A)
Explanation: Arctic haze is the phenomenon of a visible reddish-brown springtime haze in the atmosphere at high latitudes in the Arctic due to anthropogenic air pollution. A major distinguishing factor of Arctic haze is the ability of its chemical ingredients to persist in the atmosphere for significantly longer than other pollutants. Due to limited amounts of snow, rain, or turbulent air to displace pollutants from the polar air mass in spring, Arctic haze can linger for more than a month in the northern atmosphere. Hence, statement 1 is correct.
