... to aggregate in areas of low flow and are known as leaf packs. These leaf packs are then processed in situ by the stream community. The leaves that enter the stream are nutrient poor as the tree re-absorbs most of the useful sugars and amino acids. When the leaves enter the stream they begin a process called 'conditioning'. At first leaching occurs, over a period of a couple of days most of the remaining nutrients are dissolved out of the leaf. Then fungi and bacteria begin to colonise the leaves and start to break down the lignin and cellulose of which they are made. After a couple of weeks the leaves become soft enough for aquatic invertebrates to begin to feed on them. Not all leaves breakdown at the same rate. For example Alder (Alnus glutinosa) leaves break down quicker than Oak (Quercus robur) leaves. This breakdown continuum means that ...

See this essay or coursework document in full right now