Pictured left: a coral reef, an example of a marine ecosystem.
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving (abiotic), physical components of the environment with which the organisms interact, such as air, soil, water and sunlight. Ecosystems are functional units consisting of living things in a given area, non-living chemical and physical factors of their environment, linked together through nutrient cycle and energy flow.
The entire array of organisms inhabiting a particular ecosystem is called a community. The number of species making up such a community may vary from a myriad to a single species such as Desulforudis. In a typical ecosystem, plants and other photosynthetic organisms are the producers that provide the food. Ecosystems can be permanent or temporary. Ecosystems usually form a number of food webs.
Ecosystem services are “fundamental life-support services upon which human civilization depends,”i and can be direct or indirect. Examples of direct ecosystem services are: pollination, wood and erosion prevention. Indirect services could be considered climate moderation, nutrient cycles and detoxifying natural substances. The services and goods an ecosystem provides are often undervalued as many of them are without market value.
Broad examples include:
- Regulating (climate, floods, nutrient balance, water filtration)
- Provisioning (food, medicine, fur, minerals)
- Cultural (science, spiritual, ceremonial, recreation, aesthetic)
- Supporting (nutrient cycling, photosynthesis, soil formation).
Central to the ecosystem concept is the idea that living organisms interact with every other element in their local environment. Eugene Odum, a founder of ecology, stated: "Any unit that includes all of the organisms (ie: the "community") in a given area interacting with the physical environment so that a flow of energy leads to clearly defined trophic structure, biotic diversity, and material cycles (i.e.: exchange of materials between living and nonliving parts) within the system is an ecosystem. (Full article...)