Global warming harms lakes: study

July 16th, 2012 in Earth / Environment
In the fall, the body of water already turns over at a depth of between zero and 20 meters and the Planktothrix comes to the surface from depths of 15 meters. It can form visible masses (blooms) at the surface. Credit: UZH



Many large lakes in became heavily overfertilized in the twentieth century through sewage. As a result, algal blooms developed and cyanobacteria (photosynthetic bacteria) especially began to appear en masse. Some of these organisms form toxins that can compromise the use of the water. Dying consume a lot of oxygen, thereby reducing the in the lake with for the .


Burgundy blood algae grow more rapidly

The cyanobacteria Planktothrix rubescens (Burgundy blood algae) in Lake Zurich. The threads are only 0.005 by two millimeters in size, but primarily form a mass presence at a water depth of 12 to 15 meters. Credit: UZH

"The problem today is that mankind is changing two sensitive lake properties at the same time, namely the nutrient ratios and, with , ," explains Thomas Posch, a limnologist from the University of Zurich. In collaboration with Zurich Water Supply, he analyzed 40 years' worth of data in a study that has just been published in Nature .


Warmer lakes have insufficient water turnover


Hope for cold, windy winters


More information: Thomas Posch, Oliver Köster, Michaela M. Salcher und Jakob Pernthaler. Harmful filamentous cyanobacteria favoured by reduced water turnover with lake warming. Nature Climate Change. 8. Juli 2012. DOI:10.1038/NCLIMATE1581

Provided by University of Zurich

"Global warming harms lakes: study." July 16th, 2012. http://phys.org/news/2012-07-global-lakes.html