[Mission 2024] STATIC QUIZ, 26 August 2023 – Environment

Solution: b)

Statement 2 is incorrect.

Ecotone is a zone of junction between two or more diverse ecosystems. For e.g. the mangrove forests represent an ecotone between marine and terrestrial ecosystem. It may be very narrow or quite wide, but not larger than a biome which is a much larger entity. Well-developed ecotones contain some organisms which are entirely different from that of the adjoining communities.

Solution: d)

The roots of pulses and legumes contain soil enriching bacteria collectively known as Rhizobium. Therefore pulses perform biological fixation of environmental nitrogen. They also increase organic matter in the soil, improve quality and maintain its biodiversity. Pulses enhance fertility and reduce the consumption of major fertilisers required for the cultivation of food crops by millions of tonnes globally.

Solution: b)

Statement 2 is incorrect.

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.

Solution: d)

Zooxanthellae is what gives colour to corals and provide them food.

• Bleaching, or the paling of coral colour occurs; when (i) the densities of zooxanthellae decline and (ii) the concentration of photosynthetic pigments within the zooxanthellae
• There are many causes of coral bleaching.
• Major Temperature changes, extreme low tides, tectonic uplift etc. can potentially induce bleaching.
• Moreover, Sedimentation, Fresh Water Dilution, inflow of Inorganic Nutrients (e.g. ammonia and nitrate) etc. too cause the same.

Solution: b)

The energy required for the life within the biosphere usually comes from the sun. But Chemosynthetic bacteria are organisms that use inorganic molecules as a source of energy and convert them into organic substances. They do not need sunlight for their survival.

Chemosynthetic bacteria, unlike plants, obtain their energy from the oxidation of inorganic molecules, rather than photosynthesis. Chemosynthetic bacteria use inorganic molecules, such as ammonia, molecular hydrogen, sulfur, hydrogen sulfide and ferrous iron to produce the organic compounds needed for their subsistence.

Most chemosynthetic bacteria live in environments where sunlight is unable to penetrate and which are considered inhospitable to most known organisms.