Some freshwater ecosystems are acidifying rapidly as carbon dioxide emissions rise, according to research by German scientists, raising fears over fish stocks and water quality.
Only 1 percent of the world's water is freshwater, but 40 percent of all fish are found there. Globally, 70 percent of freshwater is used for agriculture, including irrigation, livestock and aquaculture.
Scientists analysed data from 1981 to 2015 in four large reservoirs in Germany. They found a continuous increase of CO2 in the water and a 0.3 rise in pH, a measure of how acidic or alkaline water is, said Linda Weiss, the study's lead author.
"This is actually faster than the oceans because the oceans aren't projected to acidify by 0.3 until 2100," she told the Thomson Reuters Foundation.
Rising CO2 levels also affect water flea, an important food source for fish, by making them less able to sense predators and defend themselves. This means more of them could be eaten in the short-term, reducing the amount of food for fish.
The first manifestation of freshwater acidification could be poor water quality because a bacteria known for producing toxins seems to thrive in high CO2 freshwater, said Caleb Hasler, assistant professor at the University of Winnipeg, who studies aquatic conservation.
A 2015 study on the Laurentian Great Lakes in North America, the largest freshwater system on Earth, found they were acidifying at the same rate as oceans. Weiss said this difference in findings may be due to the size of the water body or geology.
1 comment:
The problem of CO2 in the atmosphere being the cause of acidification of the oceans has been known for decades. I cannot recall the statistics in a scientific report of that time, but it stated that the amount of CO2 already in the atmosphere would be steadily released over time and was sufficient eventually to kill all life in the oceans. Sentient life as we know it can only exist within a small range in the acidic scale and different species, including plant life, have varying tolerances. The report concluded that we are unable to stop this process; elsewhere I have read that there are plans to remove the CO2 and neutralise this process -- an unlikely possibility under capitalism inj my book.
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"In such a world of conflict, a world
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1913 - 1960 - Albert Camus
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