[Mission 2023] STATIC QUIZ, 25 May 2023 – Environment

Solution: b)

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.

Solution: c)

Wastewater treatment has shown remarkable success in reducing water scarcity and helping safe reuse of wastewater in agriculture. By constructing wetlands with plant species such as Canna indica, lemon grass (Cymbopogon), napier (Pennisetum perpureum X Pennisetum americarnum), para grass (Urochloa mutica), typha (Typha latifolia), water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes) and a weed species Agaratum Conyzoides the chemical oxygen demand in wastewaters have been reduced.

Solution: c)

Elevated temperature typically decreases the level of dissolved oxygen of water. This can harm aquatic animals such as fish, amphibians and other aquatic organisms.

Thermal pollution may also increase the metabolic rate of aquatic animals, as enzyme activity, resulting in these organisms consuming more food in a shorter time than if their environment were not changed.

High temperature limits oxygen dispersion into deeper waters, contributing to anaerobic conditions. This can lead to increased bacteria levels when there is ample food supply. Many aquatic species will fail to reproduce at elevated temperatures.

Solution: a)

Shola forests are tropical Montane forests found in the valleys separated by rolling grasslands only in the higher elevations. They are found only in South India in the Southern Western Ghats.

• The Shola forests are generally said to be found in altitudes above 2000 metres of sea-level. Although they are found from altitudes higher than 1600 metres.
• Shola forests are a native only to the Southern Western Ghats.
• They are found only in the high-altitude mountains of the states Karnataka, Kerala and Tamil Nadu.
• Exotic invasive trees like pine, acacia and eucalyptus are largely seen in Shola forests.

Solution: d)

Light pollution is excessive brightness that causes visual discomfort.

• Skyglow is the brightening of the night sky over inhabited areas. It is caused by cluttered, bright, excessive and confusing groupings of light sources.
• It affects the reproductive cycles of those animals that depend on sensing light movements or seasonal movements to reproduce. Since birds migrate using star light, it can confuse them, and even disorient night-flying insects.
• Excessive blue light emitted from LEDs directly affects sleep pattern in Human by suppressing the production of the hormone melatonin, which mediates the sleep-wake cycle in humans.