An analysis of how chemical, physical and biological influences shape the biological communities of rivers, lakes and estuaries in temperate and tropical regions. There is an important practical component to this module that includes laboratory work and three field visits. The first piece of course work involves statistical analysis of class data. The module can be taken alongside geochemical and hydrological modules and also fits well with other ecology modules. Pre-requisite requirements: An A-level in a biological subject, a biologically biased access course or any 1st year ecology module in ENV or BIO. Students must have a background in basic statistics.