Are lakes running low on oxygen?

In one of our previous articles on this page, we have learnt about dead zones in oceans, where the dissolved oxygen is too low to support aquatic life. Dead zones are chiefly caused by the release of industrial effluents, fertiliser runoff and other pollution into water. Now, a new study has found that there is a dangerous decline in oxygen level in the world’s lakes and it has been attributed to rising temperatures because warm water holds less dissolved oxygen than cold water.

Researchers looked at samples and measurements taken from 393 lakes in temperate areas of the globe from 1941 to 2017.

They found a widespread decline in dissolved oxygen in both surface and deep water habitats. The oxygen levels had fallen by 19% in deep waters and 5% at the surface.

They pointed out that lakes have been losing oxygen three to nine times faster than the oceans, in the past 40 years.

Why is this matter of concern?

All complex life depends on oxygen and so, when oxygen levels drop, the biodiversity is affected.

The concentration of dissolved oxygen in aquatic systems helps to regulate nutrient biogeochemistry, and the quality of drinking water. It will affect the health of human populations that rely on these lakes.

As oxygen levels drop, it allows numerous types of methane-emitting bacteria to thrive. As these lakes emit more greenhouse gases, the effect of global warming is perpetuated, and the cycle continues.

What’s the solution?

Cutting emissions to tackle global warming, controlling the use of fertilisers and reducing urban sewage pollution are vital to save our lakes from oxygen depletion.

Picture Credit : Google

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