They reveal the implication of climate change in the increase of mercury in the Arctic

2023-05-05 10:40:05

And international studyco-led by researchers from the Higher Council for Scientific Research (CSIC), shows that the mercury levels in the Arctic they increased in correspondence with the increase in temperature during the climatic transition between the last glacial cycle and the Holocene (16,000-10,000 years before present).

In the current context of climate change, this paper highlights the link between thaw with the increase in natural emissions of mercury into the atmosphere and, therefore, with a greater risk for the ecosystems of the Arctic region. The results are published in the journal Nature Geoscience.

Researchers have used ice cores taken from Greenlandas part of the international East Greenland Ice Core Project, to examine the relationship between past climate variations and mercury levels in the Arctic.

Mercury levels in the Arctic region increased due to reduced ice cover caused by rising temperatures

The objective was to understand the natural sources that determine the biogeochemical cycle of mercury (a global pollutant and a toxic element for the nervous system of living beings).

The results show that mercury levels in the Arctic region increased during the transition from the last glacial cycle to the current climatic period, the Holocene (last 11,000 years), due to the reduction in ice cover caused by the temperature rise.

“This work reveals that the deposition of mercury on the surface of the Arctic ice tripled at the beginning of the Holocene compared to the last glacial cycle”, emphasizes the researcher from the Ca’Foscari University of Venice and first author of this work. Delia Segato.

“Thanks to the analysis and interpretation of paleoclimatic archives and the development of a numerical model of the atmospheric chemistry of mercury”, continues Segato, “we have concluded that the Arctic ice loss due to climate warming produced 11,700 years ago is the main cause of the increase in mercury deposition in Arctic ecosystems.

Greenland area where the ice core was extracted. / East Greenland Ice-core Project

Great environmental impact

Mercury causes a great environmental impact being present both in the air (atmosphere) and in bodies of water (hydrosphere) and in living organisms (biosphere). It accumulates mainly in terrestrial ecosystems, especially in soils.

Regarding its origin, mercury emissions into the atmosphere are not only of anthropogenic origin, but the global mercury cycle is also controlled by Natural sourcessuch as oceanic or volcanic emissions.

The global mercury cycle is also controlled by natural sources, such as oceanic or volcanic emissions.

“In the polar regions, sea ice plays a key role in controlling natural mercury emissions into the atmosphere,” he explains. Alfonso Saiz-Lopezresearcher at the Rocasolano Physical Chemistry Institute (IQFR-CSIC) and one of the two coordinators of this study.

In fact, continues Saiz-López, “it has been shown that perennial ice, sometimes several meters thick, prevents the transfer of mercury from the ocean to the atmosphere, which otherwise occurs given the volatile nature of this metal”.

Due to current global warming, the perennial ice extent in the Arctic has been reduced by more than 50% since the middle of the last century. “This work suggests that future Arctic melting may lead to a greater avoidance of mercury from the ocean to the atmosphere, with the consequent risk for Arctic populations and ecosystems”, concludes Saiz-López.

Reference:

Delia Segato, Alfonso Saiz-Lopez, et al. Climate control on Arctic mercury variability during the Last Glacial Termination. Nature Geoscience (2023)

Rights: Creative Commons.