sapro-, sapr-, sap- +
(Greek: rotten, putrid, putrefaction, decay; poisoning from bacterial action)
The saprobity system is based on the observation that in the course of the self-purification process a body of water shows distinct zones of decreasing pollution (or improved water quality); these zones are termed polysaprobic (gross pollution), alpha-mesosaprobic, beta-mesosaprobic, and oligosaprobic; the latter may be divided into alpha- and beta- oligosaprobic.
Each zone is characterized by a particular content of oxygen, organic matter, products of septic decay, and products of mineralization. Biologically, each zone affords optimal conditions for certain species and communities of organisms, the so-called "indicator" organisms.
- Polysaprobic zone, heavy pollution with sewage or other organic materials, mass development of bacteria that are involved in decomposition processes, a high rate of oxygen consumption, and a high production of ammonia and hydrogen sulfide.
- Alpha-mesosaprobic zone, vigorous oxidation processes, increased dissolved oxygen though oxygen consumption is still high, no hydrogen sulfide production, oxidation of ammonia starts.
- Beta-mesosaprobic zone, much dissolved oxygen, low oxygen consumption, mineralization of organic materials, and large amounts of the end-products of mineralization; for example, nitrates.
- Oligosaprobic zone, all mineralization processes have been completed, the dissolved oxygen content is high and oxygen consumption nearly zero; the beta-oligosaprobic level is characterized by rather moderate variety of species and low bioactivity, while the alpha-oligosaprobic level is characterized by a comparatively large variety of species and high bioactivity.
The particular saprobity zones may be characterized as follows:
2. Causing, or due to, decay of organic matter.
3. Developing in or living upon putrefying matter.
2. Soft, clay-rich, thoroughly decomposed rock formed in situ by chemical weathering of igneous and metamorphic rocks.
2. A mud rich in organic matter formed at the bottom of a body of water.
3. A fluid slime found in swamps and bogs as a product of putrefaction.
4. Putrefying sludge rich in hydrogen sulfide.