Light from cities that can be clearly visible in the night sky may have more effects on nature than before. Scientists from the Fresh Water Ecology and Fisheries Institute, which bears the name of Leibniz, found that even weak artificial lighting at night – the multiple pollution of the sky – encouraged the growth of cyanobacteria in lakes and accelerated the carbon cycle in fresh water ecosystems. Published in İş Magazine Water research.
Cyanobacteria or blue-green algae are a group of microscopic water organisms that can perform photosynthesis that convert sunlight into chemical energy. These bacteria generally form mass flowers, especially in reservoirs with high nutrient levels such as nitrogen and phosphorus. Some cyanobacteria can produce toxic substances harmful to fish, animals and even humans.
Professor Hans-Petter Grossart, the leading author of the study, said, uz We have known for a long time that many organisms in lakes live according to daily rhythms. However, even if they reach the lakes, we start to understand how much light can affect the cities, ”he said.
The experiment was carried out on a unique Lakelab research platform in Lake Sharmutselsey, where 24 closed “mini-on” ecosystems allow you to correctly monitor the changes in the ecosystems. Scientists illuminated 10 out of 15 tanks at night for a month and mimic differently light pollution. The remaining tanks remained in the dark.
The results were striking: the amount of cyanobacteria and other light -sensitive bacteria in illuminated areas were 32 times higher than the dark ones. This surprised the researchers because the lighting level was very low to stimulate photosynthesis. However, even such a light light was enough to start changes.
In addition to the increase in cyanobacterial populations, light also affected the carbon cycle in water – the composition of bacterial communities changed and the decomposition of organic substance was activated. Such changes can significantly change the balance of ecosystems and increase the risk of toxic flowering of algae that threaten not only nature, but also human health.
One of the Project Coordinators. “Light pollution may become the incomplete element of explaining the origin of the mysterious flowering of algae, especially near cities,“ Franz Helker added.
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