Mörtsjön 2.21

Mörtsjön is a small lake in Huddinge Municipality, south of Stockholm in Sweden. Part of the Orlången Nature Reserve, Mörtsjön is also one of the smaller lakes of the Tyresån Lake System,Catchment areaPrince Eugen painted some of his well-known romantic landscapes by the lake in the late 19th century. The homestead Charlottendal on the north-eastern corner of the lake is surrounded by old agricultural land where inorganic fertilisers and pesticides have never been used, and, as a consequence, contains many rare species, such as common rockrose, dithering-grass and scarlet waxy cap. The lush landscape around the lake makes it popular for walking, bathing, fishing, and other open-air activities.Environmental impactThe shallow lake is eutrophic. Levels of phosphorus are relatively high, while levels of nitrogen are normal. There are very few human structures in the catchment area, why most of nutrients reaching the lake stems from the surrounding forests. Clearfelling in the end of the 1970s caused increased levels of nitrogen in the lake over the following years and ensuing fish kill probably caused by algal bloom. The shallowness of the lake still tends to cause a shortage of oxygen, which during winters can suffocate fishes.