Ecological stoichiometry
From Wikipedia, the free encyclopedia
Ecological stoichiometry is a perspective that considers how the balance of energy and elements affect and are affected by organisms and their interactions in ecosystems. Ecological stoichiometry has a long history in ecology with early references made to the constraints of mass balance made by Liebig, Lotka, and Redfield. This research area in ecology has recently gained momentum by explictly linking the elemental physiology of organisms to the their food web interactions and ecosystem function.
Each individual organism has a chemical makeup determined by the balance of biological functions within it. For example, large trees require vast amounts of the carbohydrate cellulose for structural purposes. Or, small, fast-growing microorganisms require large amounts of nucleic acid to support rapid gain of biomass. These different substances have distinct chemical content.
The degree to which organisms maintain a constant chemical composition in the face of variations in their environment, particularly in the chemical composition and availability of their resources, is referred to as "elemental homeostasis". Like the general biological notion of homeostasis, elemental homeostasis maintains highly ordered, functional biological states. Some organisms, multicellular animals for example, have close to strict homeostasis and they can be thought of as having distinct chemical composition. Such organisms are similar to abstract molecules, with a very complex formula. Taking this approach, the stoichiometric formula for a human being is:
H375,000,000 O132,000,000 C85,700,000 N6,430,000 Ca1,500,000 P1,020,000 S206,000Na183,000 K177,000 Cl127,000 Mg40,000 Si38,600 Fe2,680 Zn2,110 Cu76 I14 Mn13 F13 Cr7 Se4 Mo3 Co1 [1]
Ecological stoichiometry seeks to discover how the chemical content of organisms shapes their ecology. Ecological stoichiometry has been applied to studies of nutrient recycling, resource competition, animal growth, and nutrient limitation patterns in whole ecosystems. The Redfield ratio of the world's oceans is one very famous application of stoichiometric principles to ecology. Ecological Stoichiometry equally considers phenomena at the sub-cellular level, such as the P-content of a ribosome, as well as phenomena at the whole biosphere level, such as the oxygen content of Earth's atmosphere.
