Environment & Ecology GK Questions with Answers – Page 27

Transpiration is the escape of water vapour from a plant, chiefly through the stomata of the leaves, and over a forest or a crop field it returns a large volume of water to the air; together with evaporation from open surfaces it is called evapotranspiration.

About ninety-seven per cent of the water on earth is salt water in the oceans, and of the small freshwater remainder the greater part is locked up as ice in glaciers and the polar ice sheets, with most of what is left held as groundwater.

The very high temperature of a lightning discharge supplies enough energy to break the triple bond of nitrogen, and the atoms join oxygen to give nitric oxide and then nitrogen dioxide, which dissolve in rain as nitrous and nitric acid and reach the soil as nitrate; this is physical or…

Nitrogenase is the enzyme complex, containing molybdenum and iron, that breaks the triple bond of the nitrogen molecule and joins the atoms with hydrogen to make ammonia; it is destroyed by oxygen, which is why a root nodule keeps leghaemoglobin to mop oxygen up.

Dry air is about seventy-eight per cent nitrogen by volume, which makes the atmosphere the great reservoir of the nitrogen cycle, yet the triple bond of the nitrogen molecule is so strong that plants and animals cannot use the gas directly and depend on fixation.

Denitrification is the reduction of nitrate to nitrogen gas, which escapes to the atmosphere and completes the nitrogen cycle; it is carried out by these bacteria in waterlogged soils where oxygen is scarce, and it is the reason farmers lose nitrogen from flooded fields.

Nitrification happens in two stages, and the first is the oxidation of ammonia to nitrite by chemoautotrophic bacteria of the genera Nitrosomonas and Nitrococcus.

Rhizobium is a bacterium that lives in a symbiotic relationship with legumes such as gram, pea, bean, groundnut and arhar, forming nodules on their roots in which it converts nitrogen gas into ammonia using the enzyme nitrogenase; this is why legumes are grown in rotation to restore soil nitrogen.

Phosphorus has no stable gaseous compound in nature, so its reservoir is rock, chiefly the mineral apatite; it enters the soil only through slow weathering, passes through plants and animals, and returns to sediments, which makes it a purely sedimentary cycle and the slowest of the common cycles.

Humus is the dark, formless material left in soil after decomposers have broken down dead leaves, roots and animal remains; it resists further microbial attack and decays only very slowly, which makes it the long term store of carbon and nutrients in soil and a key step in every biogeochemical…

That is the wording of Sustainable Development Goal 6, the water and sanitation goal. The seventeen Sustainable Development Goals were adopted by the United Nations in September 2015 as part of the 2030 Agenda, and they replaced the eight Millennium Development Goals.

A pyramid of energy is always upright because energy is lost as heat at every step of a food chain, so each higher trophic level holds less energy than the one below it.

An ecotone is the transition zone where two different ecosystems meet and mix, such as the belt between a grassland and a forest, an estuary between a river and the sea, or a mangrove strip between land and ocean.

The 2030 Agenda for Sustainable Development sets 17 Sustainable Development Goals, and these are broken into 169 targets.

An endemic species is one that occurs naturally in one particular area and nowhere else, and the Nicobar pigeon is the textbook Indian example, living in the forests of the Nicobar group of islands; the Andaman wild pig and the Narcondam hornbill are usually listed beside it.

Goal 15, called Life on Land, is the goal for land ecosystems, and its wording covers forests, desertification, land degradation and the loss of biodiversity.

Carbon monoxide is a dangerous air pollutant, but it is not counted among the major greenhouse gases, because it absorbs very little of the infrared heat leaving the earth.

Overgrazing is a cause of soil degradation, not a way to conserve soil, so it is the option that does not belong.

Nitrogen makes up about 78 per cent of the atmosphere, yet it is not a greenhouse gas. A molecule traps heat only if it can absorb outgoing infrared radiation, and that needs vibrations which change the spread of electric charge in the molecule.

The National Green Tribunal was set up by the National Green Tribunal Act, 2010, and started work on 18 October 2010 with its principal bench at New Delhi.