October 19, 2021

Biology Reporter

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Greenland: the surprising effect of melting glaciers.  Large amounts of mercury

Greenland: the surprising effect of melting glaciers. Large amounts of mercury

In Nature Geoscience, researchers describe the unexpected effect of melting glaciers. Water in rivers and fjords connected to the Greenland ice sheets contain similar amounts of mercury as polluted rivers in industrial areas of China. Scientists suggest that after entering living things, the mercury concentration increases in next steps in the food chain. Meanwhile, fish is caught throughout Greenland, among other things cod or halibut.

The authors of a study published in Nature Geoscience describe another surprising effect of melting glaciers. Extremely large quantities of mercury are found in meltwater collected in southwest Greenland. This prompts us to ask a whole host of questions about how this mercury entered the food chain, says Dr. John Hawkins of Florida State University.

The researchers explain that a typical concentration of mercury in rivers ranges from 1 to 10 ng / L, roughly the same amount as a grain of sand dissolved in an Olympic swimming pool. In Greenland waters, the researchers detected a concentration of 150 ng / L. Meanwhile, the sediments carried by the river contain mercury at a concentration of more than 2000 ng / L.

We did not expect to disclose a quantity close to what is present in these waters. Of course, we have hypotheses about what leads to these mercury concentrations, but the discovery raised a lot of new questions that we still have to answer, says one of the researchers, the professor. Rob Spencer.

Scientists suggest that after entering living things, the mercury concentration increases in next steps in the food chain. Meanwhile, there is widespread fishing around Greenland, including cod, halibut or shrimp.

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After many years working in West Greenland, we know that glaciers provide nutrients to the oceans – but discovering that they can also be a source of toxins shows an alarming dimension of the effect of glaciers on water quality and the communities that depend on it. on him. In a warmer world, it may change, indicating that more research is needed – the professor stresses. Gemma Waddham from the University of Bristol.

The discovery also illustrates the complex environmental impacts of the world’s melting glaciers.

Around 10 percent. The globe is covered with ice, which is undergoing rapid changes due to global warming. Scientists around the world are trying to understand their impact, as well as on the geochemical processes crucial to life on Earth. Professor Dr. Spencer.

However, over the past few years we have shown that this way of thinking is incorrect. He adds that this study is another study that shows that ice sheets are rich in materials important to living organisms.

The researchers also suggest that the mercury in the glaciers probably came from the Earth itself, not, for example, from burning fossil fuels. This can play a role in making decisions about how to deal with environmental pollution.

All efforts to reduce the amount of mercury have been based on the assumption that the increasing concentrations observed around the world are mainly due to human activities such as industry. However, mercury from climate-sensitive environments like glaciers can be more difficult to control, the professor notes. Hawkins.