PhD Willem Van Colen

Consequences of an increasing nitrogen to phosphorus ratio on the eutrophication of shallow lakes

Emissions of nitrogen (N) and phosphorus (P), mainly via industrial wastes or agriculture, have caused an increasing level of eutrophication (increase in phytoplankton productivity) in shallow lakes worldwide. Up to now, P was considered to be the main cause of this unfortunate trend and attempts to counter attack eutrophication focused on the reduction of this element. The resulting one sided reduction of P led to an increasing N:P ratio.

In my research, I focus on the consequences of this increasing N:P ratio regarding the level of eutrophication in the valuable and vulnerable ecosystems that shallow lakes are. Via a series of ex situ and in situ mesocosm experiments, I look at the productivity and species composition of the phytoplankton and zooplankton communities. I’m currently doing this in temperate climates (Flanders) and in the near future I will also perform experiments in a subtropical climate (Uruguay). I’m also collecting data regarding this topic in a mountain region in Ecuador (Cajas National Park).


My Publications