Ecosystem: Definition, Components and Ecosystem Services

Ecosystem is a complex, dynamic biological system composed of living and non-living parts that exchange matter and energy, structurally bounded within an area, and functionally integrated to form a self-sustaining unit – making it a fundamental structural and functional unit of the biosphere.

Sir Arthur Tansley first introduced the concept of ecosystems in 1935 to describe the dynamic connections between living creatures and their habitat.

Components of Ecosystem

The major components that make up an ecosystem can be broken down into two categories – biotic and abiotic components.

Biotic Components

The biotic components are the living things that shape an ecosystem. The main biotic components are:

• Producers – These are organisms that produce their own food through photosynthesis. Most producers are green plants, algae and some bacteria that capture energy from sunlight and convert it into food. Examples include trees, shrubs, grasses, phytoplankton, kelp, and mosses.
• Consumers – Consumers are organisms that consume other living things for nutrition. These include Herbivores, Carnivores, Omnivores and Detritivores.
• Decomposers – These organisms breakdown dead and decaying matter into simpler inorganic substances. Fungi and bacteria act as the key decomposers in an ecosystem. Examples include mushrooms, molds and certain bacteria.

These biotic components interact with one another in food chains and food webs, where energy and nutrients are transferred from producers to various types of consumers.

Abiotic Components

The abiotic components comprise the non-living elements of an ecosystem. The main abiotic elements are:

• Water – Water supports life in an ecosystem and is involved in many critical ecosystem processes like photosynthesis and nutrient transport. Rivers, lakes, seas provide water in ecosystems.
• Air – It supplies vital gases like oxygen, nitrogen, carbon dioxide for producers and consumers. Wind helps disperse seeds and spores of plants.
• Sunlight – Sunlight provides the energy source for producers to make their own food through photosynthesis. The quality and quantity of light impacts ecosystem production.
• Soil – It supplies minerals, water and air to enable plants to grow. Different characteristics of soil like pH, salinity, nutrients impact what organisms can live on it.
• Organic matter – This includes plant and animal residue and waste products that are cycled through decomposition and nutrient transfer in the ecosystem.
• Inorganic compounds – These include vital nutrients like nitrogen, phosphorus, calcium, magnesium that are absorbed from the soil and air by plants and passed through the food chain.

These abiotic factors determine and limit the growth of organisms in an ecosystem. They influence and sustain the life cycles of biotic species.

Health & Balanced Ecosystem

Ecosystems exist at varied scales, from a small pond to an expansive rainforest. But regardless of size, ecosystems rely on the interdependency of their living and non-living elements. If one component is damaged or disappears, it impacts everything else in that system. Healthy, balanced and sustainable ecosystems have elements that can reproduce and bounce back from periodic stressors.

Humans increasingly impact ecosystems globally, both intentionally through conservation efforts and unintentionally through developments like deforestation and carbon emissions.

Ecosystem Services

Ecosystem services refer to the many benefits that healthy ecosystems provide to humans and the environment. These services fall into four main categories viz. Supporting Services, Provisioning Services, Regulating Services and Cultural services.

• Supporting services represent foundational ecosystem functions like nutrient cycling, seed dispersal, and primary production. These activities facilitate basic plant and animal growth that uphold the rest of the food web. For instance, dispersing plant seeds allows vegetation to propagate while converting sunlight through photosynthesis forms the base of the energy pyramid.
• Provisioning services generate essential commodities humans directly harvest from natural systems. This includes food sources like crops, wild plants, and seafood as well as raw materials like timber, fibers, and pharmaceutical compounds derived from biodiversity. Ecosystems also provide crucial stores of fresh water, energy sources like hydropower and biomass, and minerals central to industry and technology.
• Regulating services arise from ecosystem processes that produce clean air, fertile soil, stabilized climate, cleansed water, and other foundations for human health and infrastructure. Plants absorb carbon emissions while soils, forests, and wetlands filter pollutants from waterways. Bees, birds, bats and other wildlife also perform crop pollination and pest control valued in the billions of dollars.

Lastly, cultural services refer to the array of recreation, art, spirituality, knowledge, and other intangible benefits flowing from nature-human interactions. Tourism sustains millions of livelihoods while scientific discovery propels new innovations. Beyond economic impacts, many cultures draw inspiration from wilderness or recognize intrinsic rights of non-human species to exist.