Enantiostasis

Enantiostasis is the ability of an open system, especially a living organism, to stabilize and conserve function in spite of an unstable environment. Estuarine organisms typically undergo enantiostasis in order to survive with constantly changing salt concentrations. The NSW Board of Studies defines the term in its Biology syllabus as "the maintenance of metabolic and physiological functions in response to variations in the environment" [ [http://www.hsc.csu.edu.au/biology/core/balance/9_2_3/923net.html HSC Online ] ] .

Enantiostasis is not a form of homeostasis. Rather than maintaining homeostatic (stable ideal) conditions, enantiostasis involves maintaining only functionality in spite of external fluctuations.

The term enantiostasis was proposed by Mangum and Towle [Mangum, C. P., & Towle D. W., 1977, "American Scientist" 65, 67-75] . It is derived from the Greek "enantios" (opposite, opposing, over against) and "stasis" (to stand, posture).

An example of an organism which undergoes enantiostasis in an estuary environment includes-

* Blue Legged Crabs' hemoglobin equivalent — hemocyanin — does not bind to oxygen as efficiently when the crab is in a low potassium, low sodium environment. To stabilize, the crab lowers its internal pH to allow the hemocyanin to function efficiently.