Global Changes Affect Algal Production in Northern Lakes


Globally rising temperatures and the browning of lakes can both inhibit and promote algal growth in northern lakes.

“The results in my thesis highlight the power of browning and warming to change aquatic ecosystems. Given the large-scale warming of the entire northern hemisphere, these findings are probably relevant on a global scale,” says Isolde Callisto Puts, doctoral student at the Department of Ecology and Environmental Sciences at Umeå University.

Global warming, recovery of acidification and changes in land use have caused warming and browning of northern lakes. Increased temperature and browning impact aquatic primary producers (algae) which are a major component of the aquatic food web, and thus changes in primary production affect aquatic ecology in general.

Isolde Callisto Puts research shows that increased temperatures and nutrient additions through browning increase primary production in clear lakes with low levels of dissolved organic material, while browning of humic lakes with high levels of dissolved organic material inhibits primary production through reduced light transmission.

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