Environmental Engineering Test 1 Nddc Scholarship

Although nitrogen gas (\(N_2\)) makes up about 78% of the atmosphere, most plants cannot absorb it directly in its gaseous form because of the strong triple bond between nitrogen atoms. Nitrogen fixation is the critical biological or chemical process that converts atmospheric nitrogen into ammonia or other nitrogenous compounds in the soil, which plants can then readily absorb through their roots to build proteins and DNA.

Nitrification is a two-step biological oxidation process carried out by specialized soil bacteria. In the first stage, bacteria like Nitrosomonas convert ammonia into nitrites (\(NO_2^-\)). In the second stage, bacteria such as Nitrobacter further oxidize the nitrites into nitrates (\(NO_3^-\)). This is a vital part of the nitrogen cycle because nitrates are the form of nitrogen most easily taken up and utilized by higher plants.

Transpiration is the process by which moisture is carried through plants from roots to small pores (stomata) on the underside of leaves, where it changes to vapor and is released to the atmosphere. It is essentially the 'evaporation' of water from plant surfaces. This process not only helps in the transport of nutrients and cooling the plant but also contributes significantly to the humidity of the surrounding air and the overall water cycle.

A non-renewable resource is a natural substance that is not replenished with the speed at which it is consumed. Coal is a fossil fuel formed over millions of years from the remains of ancient vegetation. Because it takes such an immense geological timeframe to form, once we extract and burn the existing coal reserves, they cannot be replaced within a human timeframe, unlike forests or wildlife which can regenerate relatively quickly.

Deforestation has a profound impact on the local and global climate. Because trees release moisture into the atmosphere through transpiration, their removal often leads to a significant decrease in rainfall in the area. While deforestation increases soil erosion and global warming, its removal directly disrupts the moisture cycle that feeds regional precipitation patterns, often turning once-lush areas into dry landscapes.

The Chipko movement was a non-violent forest conservation movement started in India in the 1970s. The word 'Chipko' means 'to hug' or 'to cling to,' reflecting the practice of villagers hugging trees to prevent loggers from cutting them down. It was a landmark effort in environmentalism that successfully raised awareness about the ecological importance of forests and the rights of local communities to protect their natural resources.

Fossil fuels (like oil and gas) and metallic minerals (like iron and copper) are classic examples of non-renewable resources. These materials are formed by slow geological processes that take millions of years to complete. As a result, the Earth contains a finite supply of these resources, and our current rate of consumption far exceeds the rate at which nature can produce more.

Conventional renewable resources are biological resources that can reproduce and replenish themselves over a relatively short period if managed sustainably. Plants, wildlife, and aquaculture (fish farming) are all examples because they have natural reproductive cycles. As long as the rate of harvest does not exceed the rate of reproduction, these populations can be maintained indefinitely for human use.

Subsurface water, or groundwater, is water located beneath the Earth's surface in soil pore spaces and in the fractures of rock formations. A dug well is a direct method of accessing this subsurface water by excavating down to the water table. Rivers, streams, and oceans are all 'surface water' sources because they are exposed directly to the atmosphere on top of the Earth's crust.

Afforestation involves planting trees on land that has not recently been covered by forest. This practice is vital for soil conservation because tree roots bind the soil particles together, preventing them from being washed away by rain or blown away by wind. Additionally, the leaf litter creates a protective layer that reduces the impact of raindrops on the soil surface, further minimizing degradation.