mardi, 14 janvier 2020 à 15:20 - Several vulnerable marine species could disappear because they can’t survive in low-oxygen environments, but stuidies suggests there are ways to counteract some of the impacts of climate change.
In February 2017 German researchers detected a major change to our oceans -- marking the first in-depth look at how much oxygen is left in the world's water, using 50 years of data.
Except a few regions, oxygen -- an element that's essential to life on land and most marine organisms -- has decreased throughout the entire ocean, with the greatest loss in the North Pacific.
Warming water is part of the problem because it weakens circulation, meaning less oxygen is transported to the deep ocean.
As these levels decline, several vulnerable marine species could disappear because they can’t survive in low-oxygen environments.
But there is hope.
A 2019 study from Cardiff University suggests improved wastewater treatment and stricter regulations can counteract some of the impacts of climate change.
The team examined thousands of locations in England and Wales over twenty years. During that time, average water temperatures increased by 0.6 degrees Celsius, but improvements in water quality offset the heating by 0.8 degrees.
"Globally, freshwaters are amongst our most threatened habitats, showing some of the largest species declines and fastest rates of extinction," lead author Dr. Ian Vaughan from Cardiff University's Water Research Institute said in a statement.
"Many freshwater species are very sensitive to temperature, with as little as a 0.5°C increase having large effects. Despite rising temperatures, many rivers in England and Wales have continued to recover from historical pollution problems over recent decades, suggesting that ongoing water quality improvements offset temperature rises."
While pollution control is not a "cure" for the impacts of climate change on waterways, Dr. Vaughan says the findings suggest water mitigation efforts could serve as a "tool" in reducing negative, climate-change related impacts to local ecosystems.