Beijing (ANTARA) - A new study has found that climate change is\ndriving a widespread and sustained decline in oxygen levels in rivers\naround the world, threatening freshwater ecosystems.<\/p>\n
The study, published in the journal Science Advances, was conducted\nby a team of researchers led by researchers from the Nanjing Institute\nof Geography and Limnology under the Chinese Academy of Sciences\n(NIGLAS).<\/p>\n
The researchers analysed data collected over nearly 40 years,\ncovering more than 21,000 river sections worldwide. They used advanced\nmachine learning to track changes in oxygen levels between 1985 and\n2023.<\/p>\n
The results were concerning. On average, rivers lost oxygen at a rate\nof 0.045 milligrams per litre per decade. Nearly 80 per cent of the\nrivers studied showed signs of deoxygenation.<\/p>\n
Tropical rivers, those located between 20 degrees south and 20\ndegrees north latitude, including many in India, were among the hardest\nhit. This finding contradicts previous predictions that rivers in\nhigh-latitude regions would be most affected by increased climate\nwarming in these areas. The study found that tropical rivers already had\nlow oxygen levels and are losing oxygen more rapidly. This makes\ntropical rivers highly vulnerable to extreme deoxygenation events that\ncan kill fish and other aquatic life.<\/p>\n
The researchers found that the decline in oxygen solubility due to\nclimate change was the main driver, accounting for nearly 63 per cent of\nthe total decrease in oxygen levels. Warmer water does not hold as much\noxygen as colder water. Changes in ecosystem metabolism, reflected by\ntemperature, light and water flow, accounted for another 12 per cent of\nthe decline.<\/p>\n
Heatwaves also played a significant role. The study found that\nextreme heat events were responsible for nearly 23 per cent of global\nriver deoxygenation, accelerating the rate of oxygen level decline by\n0.01 milligrams per litre per decade compared to normal conditions.<\/p>\n
The study also found that very low or very high water flows could\nslightly slow down deoxygenation. Low flow conditions reduced the rate\nof deoxygenation by about 19 per cent compared to normal conditions,\nwhile high flow conditions decreased it by 7 per cent.<\/p>\n
The researchers warned that declining oxygen levels threaten river\nbiodiversity as fish and other organisms struggle to survive in\noxygen-depleted waters. They urged policymakers to take action,\nespecially in tropical regions which are most in need of effective\nstrategies to address the deoxygenation crisis.<\/p>\n
\u201cThis study provides a much-needed basis for understanding and\nmitigating the decline in oxygen levels in rivers around the world. As\nclimate change continues, protecting the \u2018breath\u2019 of our rivers may be\none of the greatest environmental challenges of this era,\u201d said Shi Kun,\na researcher at NIGLAS.<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/researcher-climate-change-drives-decline-in-oxygen-levels-in-rivers-1780666933", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }