Melting glaciers: a discovery reveals a domino effect on climate

The receding glaciers in Greenland are altering the phosphorus supply in fjords, reducing the presence of algae that naturally absorb carbon dioxide. As a result, the capacity of fjords to capture atmospheric CO₂ is reduced. This research, carried out by Sophie Opfergelt's team, was made possible by exceptional samples taken in extreme areas by the Belgian organisation IMAQA, co-founded by a former student at UCLouvain.

A team of scientists from UCLouvain, in collaboration with ULB, has shed light on a little-known mechanism by which the melting of glaciers is contributing more to global warming than expected. Their study, based on exceptional samples collected in south-west Greenland, reveals that the retreat of glaciers directly affects the phosphorus cycle in fjords and their contribution to the capture of atmospheric CO₂.

In concrete terms? The team led by Sophie Opfergelt, a researcher at the Earth and Life Institute, and Victoria Strepenne, a student at the Faculty of bioscience engineering, has observed that the gradual retreat of glaciers is altering the supply of phosphorus in the fjords that border them. 

And yet this nutrient plays a key role in the development of algae, which play a part in the natural capture of carbon dioxide. The result is that a reduction in phosphorus leads to a reduction in the proliferation of algae, thereby reducing the capacity of the fjords to trap the CO₂ present in the atmosphere.

This discovery adds to an already well-known phenomenon: melting glaciers release a fine dust of rock which, when deposited on the snow, darkens its surface. Less reflective, the snow absorbs more solar energy, speeding up the melting even further. Researchers are now showing that this dynamic is not limited to the ice surface, but is also affecting ecosystems.

The rare samples behind this breakthrough were collected by IMAQA explorers. This Belgian organisation, co-founded by Gilles Denis, a former student of Earth and climate physics at UCLouvain, carries out scientific expeditions in extreme environments, particularly the polar regions.

This article was originally written in French by the AREC team of UCLouvain. It is available to be read here.

Communication of these research results resulted in significant press coverage, notably in La Libre and RTBF.