The response of phytoplankton communities to changing lake environments

In this paper, empirical relationships between the mean phytoplankton biomass and limiting nutrient availability and between the underwater extinction of light and the biomass are used to define some of the physical aspects of lake environments subject to cultural eutrophication or to corrective restoration measures. The distinctive floristic distributions of different algae among such environments are shown to be closely related to general morphological and physiological properties of the algae themselves and that species sharing similar size- and shape-adaptations also share similar ecological growth and survival strategies. From these general predictions of the responses of phytoplankton to changing lake environments, it is deduced that deep lakes are slower to respond than shallow ones but that the transition between nutrient-and light-limitation is relatively abrupt: ‘resilience’ of the system to restoration measures may be an expression of their progress towards the transition. Presented at the International Conference on Lake Restoration in Zürich, 3–4 November 1986