干旱区生态环境知识资源中心

Holocene paleolimnological records (diatoms, organic content, spectrally inferred sediment chlorophyll-a) from three West Greenland lakes (similar to 67 degrees N) situated along a transect from the outer coast to a nunatak at the periphery of the Greenland Ice Sheet are used to explore the nature of regional postglacial lake development and its relationship to Holocene climate evolution. The lakes were deglaciated asynchronously by approximately 4 ka (earliest on the coast) and thus their sediment records document different starting points of Holocene ontogeny, both temporally and paleoclimatically. Despite similar time-transgressive characteristics of the diatom stratigraphies, overarching climatic factors, principally effective moisture, and eolian inputs, govern individual lake development. The transition to Neoglaciation between 5.6 and 4 ka BP marks a shift toward a cooler, moister, windier climate from the aridity and higher temperatures of the mid-Holocene (8-6 ka BP). A shift toward increased aridity, windiness, and eolian activity is documented in the interior lakes over the last 500 years. These lake records demonstrate the sensitivity of freshwater lakes in arid regions to changes in effective moisture and highlight the role of wind and eolian activity in Arctic lake environments.