Ecological stoichiometry

Ecological stoichiometry considers how the balance of energy and elements affects and is affected by organisms and their interactions in ecosystems. Ecological stoichiometry has a long history in ecology with early references to the constraints of mass balance made by Liebig, Lotka, and Redfield, and has recently gained momentum by explicitly linking the elemental physiology of organisms to their food web interactions and ecosystem function.

Most work in ecological stoichiometry focuses on the interface between a consumer and its food. This interface, whether it is between plants and their resources or large herbivores and grasses, is often characterized by dramatic differences in the elemental composition of each participant. Consider termites which have a body C:N of about 5 but consume wood with a C:N ratio of 300-1000. Ecological stoichiometry primarily asks:

Elemental imbalances are a mismatch between the elemental demands of a consumer and that present in its resources. Elemental imbalances arise between grazers and their food whose foods vary considerably in their elemental composition more often than in animals who have less elemental flexibility. For example, carbon to phosphorus ratios in the suspended organic matter in lakes (i.e., algae, bacteria, and detritus) can vary between 100 and 1000 whereas C:P ratios of Daphnia, a crustacean zooplankton, remain nearly constant at 80:1. There are a number of physiological and evolutionary explanations for these differences in elemental composition that are related to the types of needed resources, their relative availability in time and space, and how they are acquired.

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