B.O.D (Biochemical Oxygen Demand)
The amount of dissolved oxygen required to degrade organic material in a given volume of water via aerobic biological activity.
Organic = any living plant or animal, remnants or matter.
Changes of community over time - organisms changing the physical environment (edaphic factors) that then allow other communities to become more established,then replace former species via competition, latter seres are more complex -climax communities.
Edaphic = soil profile
Ecosystem & Biome
Ecosystem: A community if interdependent organisms and the physical environment they inhibit. Including abiotic and biotic factors.
Biome: A collection of ecosystems sharing similar climatic conditions.
An excess input of nutrients into a freshwater ecosystem, mostly from anthropogenic activity such as fertilizer use which involve harmful nitrates and phosphates, sewage and detergents.
Leading to algae blooms which prevent photosynthesis and deplete oxygen levels.