8.3 Primary production and vertical export8 Eutrophication, primary production and vertical export8.1 Introduction8.2 Eutrophication

8.2 Eutrophication

The term eutrophication derives from the Greek roots eu (`well') and trope (`nourishment') and could thus be translated into well-fed, well-nourished. With the term eutrophication we imply that the ecosystem, not an individual, is well-nourished and that nutrients or biomass are supplied to a particular recipient. Eutrophication is not a clearly defined term and there are various definition such as:

  1. The process of changing the nutritional status of a given water body by increasing the nutrient resources [391]
  2. An increase in the rate of organic carbon production in an ecosystem [342]

In most cases we use definition 1 and this will also be the case in the present text. Thus we focus upon the supply to and the dynamics of nutrient resources in a water body. Eutrophication can entail either the process or the result. One has further to distinguish between natural eutrophication that is caused by winter accumulation, precipitation, vertical mixing, upwelling, river run-off and entrainment of nutrients. Climatic variability obviously influences and modulates the nutrient availability of a recipient and natural eutrophication thus varies over time. The natural variability in eutrophication is often poorly known, in particular because it may be camouflaged by cultural eutrophication , which is any type of nutrient discharge caused by anthropogenic activity, e.g agriculture run-off, sewage, atmospheric deposition, changes in water discharge etc.


8.3 Primary production and vertical export8 Eutrophication, primary production and vertical export8.1 Introduction8.2 Eutrophication