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Toxic algae have become more intense in the last 30 years



A new study from Monday seems to confirm an unpleasant reality: The potentially toxic algae bloom in freshwater lakes around the world have become more intense over the last 30 years. And while climate change is not the only reason why flowering has worsened, rising temperatures are likely to make it difficult to restore lakes.

For their study, researchers at Stanford University and NASA used data from Landsat 5 in the vicinity – a single satellite that traveled about and 30 years on earth until its decommissioning in 2013. At that time, they used a computer algorithm borrowed from Google Earth Engine to identify algal blooms in the largest lakes in the world.

"Better data is available in more recent years than tools like MERIS and MODIS," study author Anna Michalak, a senior researcher at the Stanford Institute for Science in Carnegie, told Earther via email. "However, the goal here was to obtain the longest records possible using a single approach, both over time and in a large number of lakes around the world."

Overall, they examined the trends of algae in 71 large lakes located in 33 countries. in six continents. They found that in 68 percent of the lakes the peak flowering intensity in the summer worsened, while the flowering intensity decreased only in 8 percent of the lakes at the same time. The same model was valid for a particularly dangerous species of algae created by bacteria called blue-green algae, which can be toxic to the wild, pets and humans .

The results published in Nature Monday, give more evidence that toxic blooms are indeed becoming more widespread worldwide and "counter the hypothesis that increased reporting of toxic blooms is a by-product of increased scientific attention, ”the authors wrote.

While there seems to be a link between climate change and these booms, but the link is complex. Michalak and her co-authors did not find a consistent link between warming temperatures and the chance of more intense flowering in lakes worldwide. Michalak said this probably means that algal blooms can be influenced by many different factors, depending on the environment of the individual lake. And while these factors may include temperature, it may also include rainfall or fertilizer nearby uses.

"However, it is a constant finding that only lakes that have warmed less (or actually cooled) have been able to maintain gains in water quality," she added.

In other words, even if climate change does not make flowering in one particular lake more common, it will still try to manage them at nightmare for scientists and governments around the world. Already, the authors note, algae blooms in The US costs the country $ 4 billion a year, thanks to the damage it can cause and drinking water, agriculture and the tourism industry in the area. They can also be deadly, such as the wave of pet deaths in the summer associated with blue-green algae demonstrated this year.

One of the key findings of the study, Michalak said, "is that climate change will also benefit us in many other ways, such as maintaining water quality.

"The second uptake," she added, "is that water management strategies need to take into account the fact that temperatures and rainfall change. This will increase the chance of success of these strategies. “


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