JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III ENVIRONMENTAL MANAGEMENT IN MINES Previous Question Paper (February - 2022 - R18)

An ecosystem is the fundamental unit of ecology, comprising the interaction between a community of living organisms (biotic components) and their physical environment (abiotic components).

Classification of Ecosystems:

1. Natural Ecosystems: Operate without human interference. These are further divided into:
   • Terrestrial: Forest, grassland, and desert ecosystems.
   • Aquatic: Freshwater (lotic like rivers, lentic like lakes) and marine (oceans, estuaries).
2. Artificial (Man-made) Ecosystems: Maintained by humans, such as croplands, dams, gardens, and urban ecosystems.

Structure of Ecosystems:

The structure is defined by the organization of its components:

1. Abiotic Components: Non-living physical and chemical factors including inorganic substances (C, N, P, water), organic compounds (proteins, lipids), and climatic factors (temperature, light, humidity).
2. Biotic Components:
   • Producers (Autotrophs): Green plants and algae that synthesize food via photosynthesis.
   • Consumers (Heterotrophs): Organisms that feed on others, categorized as primary (herbivores), secondary (carnivores), and tertiary (top predators).
   • Decomposers (Saprotrophs): Bacteria and fungi that break down dead organic matter, recycling nutrients back into the soil.

Function of Ecosystems:

Ecosystems function through the continuous flow of energy and the cycling of nutrients:

1. Energy Flow: Energy enters the system via solar radiation, is captured by producers, and moves through trophic levels. This follows the 10% law, where only about 10% of energy is transferred to the next level, resulting in a unidirectional flow.
2. Nutrient Cycling (Biogeochemical Cycles): Essential elements like carbon, nitrogen, and phosphorus circulate between biotic and abiotic components, ensuring the sustainability of life.
3. Primary Production: The rate at which biomass is produced by autotrophs.
4. Decomposition: The breakdown of organic matter, which is critical for nutrient replenishment and ecosystem maintenance.

Biogeochemical cycles represent the movement and transformation of chemical elements and compounds between the living (biotic) and non-living (abiotic) components of an ecosystem. These cycles ensure the continuous recycling of essential nutrients required for life, maintaining the stability and productivity of ecosystems.

The cycles are broadly categorized into two types:

1. Gaseous Cycles: These involve elements that primarily exist in the atmosphere or oceans, such as the Carbon, Nitrogen, and Oxygen cycles. These cycles are relatively fast and global in nature.
2. Sedimentary Cycles: These involve elements that are primarily stored in the Earth's crust, such as the Phosphorus and Sulfur cycles. These cycles are slower and involve the weathering of rocks and sedimentation processes.

For example, in the Carbon cycle, carbon dioxide is absorbed by plants during photosynthesis to produce organic matter, which is then transferred through the food chain and released back into the atmosphere via respiration and decomposition.

Ecosystem value refers to the total economic and intrinsic worth of the goods and services provided by natural systems to humanity. These are categorized into:

1. Provisioning Services: Direct material benefits such as food, water, timber, fiber, and genetic resources.
2. Regulating Services: Benefits obtained from the regulation of ecosystem processes, including climate regulation, flood control, water purification, and pollination.
3. Supporting Services: Fundamental processes necessary for the production of all other ecosystem services, such as nutrient cycling, soil formation, and primary production.
4. Cultural Services: Non-material benefits including aesthetic, spiritual, educational, and recreational values.

The valuation of these services is crucial for environmental management, particularly in mining, to account for the loss of natural capital and to justify the costs of reclamation and sustainable development practices. Integrating these values into economic decision-making prevents the over-exploitation of natural resources and ensures the long-term viability of the environment.