Changes in the phytoplankton of Oak Mere, following the introduction of base-rich water

The addition of calcium-rich borehole water to Oak Mere resulted in significant changes in the quality and periodicity of the phytoplankton. The possible roles of the increases in calcium, pH, nitrogen and silica content are discussed in relation to the ecology of the algae which subsequently colonised the lake. pH is considered to be the most important factor, particularly in the case of blue-green algae, though silica content is thought to be equally important in the case of the diatoms.