|Site types that use this protocol|
Many water quality problems in inland waters are related to the growth and accumulation of phytoplankton, the microscopic algae which dominate the pelagic environment. Phytoplankton provides an important source of food for many aquatic organisms and plays a key role in nutrient cycling. The simplest method of estimating the biological productivity of a lake is to measure the concentration of phytoplankton chlorophyll present during the growing season. Some water quality problems are, however, caused by qualitative rather than quantitative changes in the phytoplankton so it is also useful to know what species are present at different times of the year.
Species presence and abundance are recorded through fortnightly sampling at lake sites only. Chlorophyll a measurements are made weekly for rivers, fortnightly for lakes.