Limnology began as the oceanography of one Swiss lake
In the nineteenth century François-Alphonse Forel studied Lake Geneva so thoroughly that he invented a new science to describe it. He called limnology the oceanography of lakes. Today it covers every inland water body, fresh or salty, from ponds and rivers to wetlands and underground aquifers.
The name joins the Greek limne, lake, with the suffix for study. Limnologists look at the biology, chemistry, physics and geology of both natural and artificial waters, and they split them into two broad kinds: running, or lotic, systems such as streams, and standing, or lentic, ones such as lakes. Unlike freshwater biology, the field also takes in inland salt lakes. Forel's work spread quickly; it influenced Benedykt Dybowski's studies of Lake Baikal, and in 1922 the German zoologist August Thienemann and Swedish botanist Einar Naumann founded the International Society of Limnology.
Light shapes a lake's life. The upper band where sunlight reaches far enough for plants to grow is the photic zone; below it lies the dark aphotic zone. Solar energy even drives the daily up-and-down migration of zooplankton. Heat divides lakes too. The warm surface layer, the epilimnion, absorbs radiation; beneath it, in the thermocline, temperature drops sharply; and the cold hypolimnion sits at the bottom. Clearer water lets heat penetrate deeper, but warming always fades rapidly with depth.
Where a lake's food comes from depends on its size. Carbon and nutrients washed in from outside, such as leaves and soil, are called allochthonous; those made inside, mainly by algae and microbes, are autochthonous. Streams and small lakes run mostly on imported material, while big lakes, like the ocean, feed mainly on their own production.
The field keeps widening its lens. Landscape limnology examines how each water body connects to its drainage basin, and global limnology studies the part inland waters play in the planet's biogeochemical cycles. In the United States, the University of Wisconsin-Madison became an early centre, with figures such as Edward A. Birge helping build its Center for Limnology.
Source: Limnology
