Daily Quiz: UPSC Prelims Marathon (Environment) – April 25, 2020

Both statements are incorrect.

Statement 1 is incorrect: Bioaccumulation is the process by which toxins enter the food web by building up in individual organisms. Bioaccumulation occurs at the base of a food web, usually within primary producers like phytoplankton. These microscopic photosynthetic organisms absorb POPs directly from the seawater and accumulate them in their bodies over time. The toxins build up in their tissues because they are absorbed from the water at a rate faster than they can be metabolized.

Statement 2 is incorrect: Bio-magnification is the process by which toxins are passed from one tropic level to the next (and thereby increase in concentration) within a food web. Bio-magnification occurs when slightly larger organisms called zooplankton feed upon the contaminated phytoplankton and in turn absorb POPs into their own tissues at a higher concentration. The more contaminated phytoplankton a zooplankton eats the more pollutants it will have in its body. In other words, the POPs can be passed from producer to consumer (to consumer, to consumer, and so on…) Bio-magnification can continue all the way up the food web or chain.

Persistent organic pollutants (POPs) are a group of chemicals possessing the following characteristics:

• They are highly toxic to humans and wildlife (harmfulness);
• They can last for many years in the environment before degrading into less dangerous forms (persistence);
• They bio-accumulate in the food chain (bio-accumulation);
• They are transported over large distances through air and water and can be found worldwide (long-range transport).

Nitrogen is a critical limiting element for plant growth and production. It is a major component of chlorophyll, the most important pigment needed for photosynthesis, as well as amino acids, the key building blocks of proteins. It is also found in other important bio-molecules, such as ATP and nucleic acids. Even though it is one of the most abundant elements (predominately in the form of nitrogen gas (N2) in the Earth’s atmosphere), plants can only utilize reduced forms of this element. Plants acquire these forms of “combined” nitrogen by: 1) the addition of ammonia and/or nitrate fertilizer (from the Haber-Bosch process) or manure to soil, 2) the release of these compounds during organic matter decomposition, 3) the conversion of atmospheric nitrogen into the compounds by natural processes, such as lightning, and 4) biological nitrogen fixation.

Himalayan tailless bush blue, Arhopala ganesa ganesa, is a butterfly that is usually present in the elevation between 1200 meters and 2400 meters in the states of Jammu & Kashmir and Uttarakhand. It later recorded an altitude 3577 meters in Askot Wildlife Sanctuary in Uttarakhand. Researchers believe that these butterflies have migrated in search of a suitable climate where the climates in several Himalayan mountain ranges have already noticed significant changes.

The Commission on Ecosystem Management (CEM) is one of the six expert commissions of IUCN. CEM provides expert guidance on integrated approaches to the management of natural and modified ecosystems to promote biodiversity conservation and sustainable development. The commission promotes the adoption of and provides guidance for ecosystem-based approaches to the management of landscapes and seascapes and builds resilience of socio-ecological systems to address global challenges.