It is not just the seas and lakes that are becoming increasingly warmer and have increasingly lower oxygen levels due to global warming. This is also the case with rivers, as a team of researchers has now shown in a study of more than 580 rivers in the US and 216 rivers in Central Europe.
From 1981 to 2019, warming was recorded in 87 percent of them and a loss of oxygen in 70 percent, reports the team of scientists with Austrian participation in the journal ‘Nature Climate Change’.
“We know that the warming climate has led to warming and oxygen loss in the oceans, but we didn’t expect this to happen in flowing, shallow waters,” said study author Li Li of Pennsylvania State University (US). the University of Natural Resources and Life Sciences (Boku) Vienna.
Finally, the flowing water in rivers and streams facilitates the exchange of gases between air and water, and light promotes photosynthesis and therefore oxygen production, the researchers write in the article. But the results of the current study would “show significant impacts on water quality and the health of aquatic ecosystems.”
The Austrian rivers were also affected
For the study, the researchers trained a deep learning model that used data about weather, water quality, topography and land use, among other things, to reconstruct the daily water temperature and oxygen content of the rivers studied (152 of which are in Austria). and predict them for the future.
As a result, water temperatures in rivers are rising faster than that of oceans, but slower than that of lakes. The average warming of river water per decade was 0.16 degrees Celsius in the United States and 0.27 degrees Celsius in Central Europe, which is due to the increase in air temperature in 85 percent of rivers.
According to the study, urban rivers have warmed the fastest in the recent past, partly due to heat islands and warm wastewater, while rivers flowing mainly through agricultural areas have seen the slowest increase in water temperature while experiencing the fastest oxygen decline.
Certain fish species may become extinct
Looking ahead, the model predicts that changes in water temperature and oxygen depletion will continue to increase by 2100. Over the next seventy years, certain fish species, especially in the United States, could become completely extinct due to prolonged periods of very low oxygen concentrations.
In contrast to watercourses in the US, there is hardly any danger of very low oxygen concentrations in the Austrian streams and rivers examined. “Nevertheless, under the conditions of the examined climate scenarios in Austria in the current century, an almost nationwide increase in temperatures and a decrease in oxygen concentrations in rivers can be expected,” explains Christoph Klingler from the Boku Institute for Hydrology and Water Management.
“Trout region will experience shrinkage”
This would further harm the animals living in the water, as their oxygen requirements also tend to increase as the water temperature rises. One consequence of this, for example, is the shift of habitats towards the source, “which means that the trout region in particular will decrease in size,” says Klingler.
Source: Krone
I am an experienced and passionate journalist with a strong track record in news website reporting. I specialize in technology coverage, breaking stories on the latest developments and trends from around the world. Working for Today Times Live has given me the opportunity to write thought-provoking pieces that have caught the attention of many readers.
