Mystery of Expanding ‘Dark Zone’ in Greenland Finally Solved
A puzzling phenomenon affecting the Greenland ice sheet – the emergence and spread of “dark zones” – has been explained by researchers who discovered that dust rich in phosphorus is a key factor. This finding is significant as the Greenland ice sheet is the second largest in the world, covering approximately 656,000 square miles, an area three times the size of Texas, and is currently losing around 500 gigatons (500 billion tons) of ice each year.
During the Arctic’s winter months, when sunlight is limited, ice algae from species Ancylonema nordenskioeldii and within the genus Mesotaenium remain dormant within the ice. As temperatures rise and the ice melts in the spring, these algae slowly migrate toward the surface.
Upon reaching the surface, the algae are exposed to sunlight, enabling photosynthesis and growth. While typically green in color, prolonged sun exposure causes the algae to darken, turning black. This darkening effect reduces the ice’s reflectivity, causing it to absorb more sunlight – a feedback loop that accelerates melting. Understanding these processes is crucial for accurately modeling and predicting the impacts of climate change on polar regions.
According to the National Snow and Ice Data Center (NSIDC), the Greenland ice sheet is currently in a precarious state. The research, detailed in reports from January 28, 2021, highlights the complex interplay between biological activity and the physical properties of ice in a changing climate.
