[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/04/EW-05-25-12-Ecosystem-Definition1.mp3|titles=EW 05-25-12 Ecosystem Definition]
In their field studies, ecologists are often overwhelmed by the complexity of nature. Many decades ago, the ecosystem concept was developed to help organize scientific studies of the environment. An ecosystem is a subunit of nature, with easily recognized boundaries that allow scientists to measure inputs and outputs of materials from well defined areas of nature.
Lakes are some of the easiest ecosystems to recognize: they have a top and bottom boundary and a shoreline that surrounds their lateral extent. An ecosystem scientist can measure the input of rainwater to the surface of the lake, the runoff waters that are received from the surrounding land, and the losses of water to evaporation, seepage or outflow.
Often ecologists define the extent of a forest ecosystem by its watershed or catchment—the area of forested land that is drained by a particular stream. When they are interested in forest nutrition, these scientists can measure the inputs of nitrogen from rainwater, from deer entering the particular watershed, and from runoff waters that drain nitrogen downstream.
A nutrient budget—in this case for nitrogen—can be developed to ascertain the natural sources of nitrogen for plant growth and to assess human impacts on nitrogen supplies.
Ecosystems defined for study can be quite large—entire counties—or quite small, such as the organisms under a particular rock. Even cities, such as Manhattan, might be recognized and defined as an ecosystem. The importance of the ecosystem concept is that it allows scientific studies of nature to proceed more easily—providing real answers to today’s environmental problems.
Photo, taken on August 24, 2011 using a Nikon D3100, courtesy of Barbara via Flickr.