Pelagic nutrient cycles

Ecology, while primarily a field of basic research, also aims to function as a predictive tool for management. Notable examples include Vollenweider's models that link phosphorus load to water renewal time and algal biomass in lakes. These models, utilizing a few accessible input parameters, have become essential for global lake management, particularly in addressing eutrophication and algal blooms. The foundation of this success lies in the observed relationship between phosphorus concentration and phytoplankton biomass in most lakes. Although these relationships are often depicted in log-log diagrams, aquatic ecologists may wonder about the variability despite the overall correlation when plotted on a linear scale. It is indeed possible to predict algal biomass levels based on phosphorus load, yet some lakes provide optimal conditions for phytoplankton communities, while others yield significantly lower biomass under similar phosphorus loads. However, growth has its limits; the predictive accuracy of phosphorus load diminishes as the load increases, especially affecting higher trophic levels like zooplankton and fish. Increased enrichment often leads to reduced efficiency in energy transfer within food web compartments.