Measurements of Eutrophication and Trends

To understand the process of cultural eutrophication, an investigator should measure for a number of years not only the nutrient flux but also the numbers, rates of production, and types of various plants and animals present in a body of water. Various investigators have attempted to measure cultural eutrophication by determining the changes in species and number of certain organisms. Other investigators measure the effect of the biological communities on specific physical-chemcal properties of water. Significant errors can occur in the calculation of nitrogen and phosphorus budgets. Examples are presented of measurements obtained since the turn of the century which demonstrate possible errors in interpretation of changes in cultural eutrophication.