NASA has announced that it will award the Distinguished Public Service Medal, its highest honor, to astronomer Yervant Terzian, the Tisch Distinguished Professor Emeritus. Professor…
There is a dark zone on Greenland’s ice sheet which is getting darker in recent years. And now scientists discover what is the real problem. As we published the article the headline of “Greenland Has a Strange Dark Zone that Is Getting Darker” we indicated that the zone is a stripe of fast-melting ice towards the south-west of the ice sheet. It’s about 400 kilometers (248 miles) in length and 100 kilometers (62 miles) at its widest point. Besides being a dark zone it is also known as the ablation zone. In addition to them, it melts faster compared to other sections of the ice sheet. Earlier theories regarding to the darkening is the presence of water on top of the ice sheet. However, a new study published in the journal Nature Communications claimed that this is due to impurities such as carbon and ice-dwelling algae. The researchers used a drone to capture images of a section of the dark zone in Greenland’s ice sheet. Techtimes pointed out “Algae require nutrients and food, particularly, organic carbon, dust, and water. A finely distributed layer of dust, as well as black carbon that gives nutrition to dark-colored algae, cover the dark zone. Similarly, a slight increase in atmospheric temperature and liquid water production seem to promote algae colonization across the ice sheet.” “In summer, these are plentiful, and the algal bloom takes off. Because algae are dark in color, they reinforce the dark zone,” Hubbard said.
According to the researchers the surface impurities composing of dust, black carbon and ice algae are the main contributors to the dark patch that threatens to speed up melting.
“Distributed surface impurities-an admixture of dust, black carbon and pigmented algae-explain 73% of the observed spatial variability in albedo and are responsible for the dark zone itself,” the researchers wrote in their study.