The Greenland Ice Sheet (GrIS) has become the largest single source of sea-level rise. Soot, minerals and blooming pigmented algae developing in supraglacial e surface environments directly affect snow and ice darkening, lowering their albedo and thus increasing surface melting by up to 26% locally. Accuracy of albedo models is fundamental for the prediction of future GrIS melt dynamics. However, crucial information, such as the 3D distribution of mineral-soot-microbe particle aggregates within the ice matrix as well as average sizes, depth and interaction between microbes, minerals and ice crystals in the first meter of ice, remain unknown. To address this gap, we want to use the cryo-CT capabilities of ID19 and analyze ice cores from Greenland to elucidate the influence of biological material and minerals on the structure of glacier ice. Such information is crucial for our ability to predict future melting rates of the GrIS.