Onset of long-term cooling of Greenland near the Eocene-Oligocene boundary as revealed by branched tetraether lipids

The Eocene-Oligocene (E-O) boundary interval is considered to be one of the major transitions in Earth's climate, witnessing the first major expansion of the East Antarctic Ice Sheet. However, the extent of the associated climatic cooling, especially for high northern latitude continental landmasses, is poorly constrained. In this study we reconstruct the first mean annual air temperature (MAAT) for the Greenland landmass during the late Eocene and early Oligocene by applying a new proxy based on the distribution of branched tetraether lipids derived from soil bacteria preserved in a marine sediment core from the Greenland Basin. The temperature estimates are compared with a composite continental temperature record based on bio-climatic analysis of pollen assemblages. Both proxies reveal comparable late Eocene MAATs of ~13-15 °C and a gradual long-term cooling of ~3-5 °C starting near the E-O boundary. These data are in agreement with other MAAT reconstructions from northern midlatitude continents and suggest a general cooling of the Northern Hemisphere during the E-O transition.

National nitrogen budget for Denmark (excel-file 125 kB)

The data describe the flows of nitrogen between different pools and economic sectors within Denmark. The data are stored in an Excel spreadsheet that is divided into a number of worksheets. The National worksheet contains the national flows of nitrogen for the years 1990 to 2010 (note that for some flows, the data series is not complete for all years). These data underlie the national nitrogen flow figures in the main text of the paper. The remaining worksheets contain the data that underlie the figures presented in the detailed description of nitrogen flows between pools/sectors, that is in the Supplementary Material associated with the paper.