Våtmarkens kapacitet - kan en våtmark optimeras för att minska såväl eutrofiering som brunifiering?

Sammanfattning: Due to changes in land use, as well as impacts from the climate change, our inland waters are now exposed to problems such as eutrophication and brownification. This complicates management to develop clean drinking water, as well as it leads to anoxic bottoms and reduces primary production. This literature review aims to see if wetlands can work as a natural filter to reduce both nutrients (nitrogen and phosphorous) and water colour, in terms of dissolved organic carbon, by looking at the levels of changes of the concentrations at the outflow with that at the inflow. This study tries to find similarities between the wetlands physical characteristics to see if there are some potential parameters that is important for an optimized wetland system. Water colour and nutrient samples are also taken at the in- and outflow of six different located wetlands, to add to the already existing data. This study shows that comparisons between wetlands is hard to do, but that some parameters may be of importance. The percentual DOC export concentration increases significantly as the wetland to catchment area ratio increases (R2= 0,30, p-value: 0,04), which may state that land use and the percentual occupation of wetland within the catchment is of importance. A constant flow seems to be important to reduce all three parameters, as well as a residence time that is not too long, nor to short. However, more studies should be done to fully understand how wetlands can be optimized, with more parameters involved.