Communities of red algae are contributing to the melting of the Greenland ice sheet, according to a study by the University of Bristol. The algae, which are thriving in increasingly warm conditions, turn the ice pinkish-red and reduce its ability to reflect sunlight, increasing the amount of light absorbed and therefore melting. The blooms can contribute up to 13% more ice melt over a season. The Greenland ice sheet is the largest in the Northern Hemisphere and loses 270 billion tons of ice each year. If it melted entirely, it would raise sea levels by 20 feet.