The Greek word 'oikos' refers to the home or place of habitation, 'logia' means 'the study of'. Ernst Haeckel was the first to combine the two words in 1873 to create the German word 'Ökologie'. In English this is ecology and is the study of where organisms live and how they interact with their environment.
In scientific terms ecology can be defined as: 'A branch of biology that deals with the distribution, abundance and interactions of living organisms at the level of communities, populations, and ecosystems, as well as at the global scale'.
Aquatic ecosystems are home to a myriad of organisms.
Source: Khayat 2008
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The spatial distribution and abundance of an organism is largely determined by the abiotic or physiochemical factors of its environment. Abiotic factors are: geological factors such as the chemical nature of the bedrock; climatic factors such as temperature and sunlight; hydrological factors such as stream flow; or the availability of nutrients and levels of pollution in the environment. Throughout evolution, organisms have adapted to fill particular environmental niches and to function optimally under a specific set of abiotic conditions. This evolutionary process of adaptation is also true for biotic interactions (Putman and Wratten 1984). Species have evolved to survive optimally in their niche and are adapted to obtain nutrients, reproduce and defend themselves against predators.
Ecology is a complex study even at small scales and for the purposes of this River Awareness Kit will focus on only one type of ecosystem - the aquatic ecosystem - and the organisms found within it.
