Scientists have been able to find out that controls the production and growth of fish in lakes by comparing the clear mountain lakes to the brown forest lakes. This new research moves away from the conventional truths that state that the productivity of a lake and its dwellers is based on the nutrients available like phosphorous. According to Jan Karlsson who is associate professor at the CIRC (climate impacts research center). The sunlight cannot penetrate more than around two meters in the brownest lakes. But in clear mountain lakes the sunlight can reach down to great depths i.e.  15-20 meters which often leads to the production of algae on the bottoms of the lakes.

The majority of the lakes in the world are small and they have poor nutrients, they also contain organic matter which was washed down into the water from surrounding lands. It is this very organic material which gives the lakes their brown color and makes it impossible for light to reach deep below. In order for the algae to grow at the bottom of the lake it need sunlight for photosynthesis. The algae acts as food for many of the lake dwellers which include fish. Which is why negative consequences are borne when light cannot reach to the bottom of the lake.

The findings of this research conclude that climate change can disrupt the production in many lakes around the world. The higher the temperature and more permafrost is thawed along with various shifts in precipitation, can lead to a rapid change in the organic material in lakes. Also longer durations of hot temperature can lead to vegetation climbing up higher on mountains and mountainsides. This would thus lead to more organic material transported to lakes in surrounding areas.

According to Jan Karlsson we are in for more brown lakes which have reduced productivity owing to climate change. As climate changes further more and more lakes are going to become brown and there is going to be a big loss of productivity in these lakes. This study is probably the first real study which charts the effects that climate change has on our lakes.

However there needs to be more research done into lakes and how climate change will affect the dweller of these lakes. It also needs to encompass the introduction of new lake dwellers and an increase of a few old ones. The long term effects of these on the fish in the lakes also need to be studied closely as many fish living deep within brown lakes loose their eyesight and develop other senses.  This initial research merits further study which will also help scientists come up with a conclusion to the problem after which a solution could be sought.

This study was officially funded by the Swedish Research Council Formas with collaborative work done by Jan Karlsson at the CIRC (Climate Impacts Research Center). It also included scientists from the Department of Ecology and Environmental Sciences, Umeå University.