Roundup: Karakoram, Ice Core, and Chile
Karakoram Glaciers in Balance
From the Journal of Glaciology: “An anomalously slight glacier mass gain during 2000 to the 2010s has recently been reported in the Karakoram region. We calculated elevation and mass change using Digital Elevation Models (DEMs) generated from KH-9 (a series of satellites) images acquired during 1973–1980… Within the Karakoram, the glacier change patterns are spatially and temporally heterogeneous. In particular, a nearly stable state in the central Karakoram (−0.04 ± 0.05 m w.e. a−1 during the period 1974–2000) implies that the Karakoram anomaly dates back to the 1970s. Combined with the previous studies, we conclude that the Karakoram glaciers as a whole were in a nearly balanced state during the 1970s to the 2010s.”
Read more about this study here.
Dust in Ice Core Reflects the Last Deglaciation
From Quaternary Science Reviews: “The chemical and physical characterization of the dust record preserved in ice cores is useful for identifying of dust source regions, dust transport, dominant wind direction and storm trajectories. Here, we present a 50,000-year geochemical characterization of mineral dust entrapped in a horizontal ice core from the Taylor Glacier in East Antarctica. Strontium (Sr) and neodymium (Nd) isotopes, grain size distribution, trace and rare earth element (REE) concentrations, and inorganic ion (Cl− and Na+) concentrations were measured in 38 samples, corresponding to a time interval from 46 kyr before present (BP) to present… This study provides the first high time resolution data showing variations in dust provenance to East Antarctic ice during a major climate regime shift, and we provide evidence of changes in the atmospheric transport pathways of dust following the last deglaciation.”
Read more about the findings here.
Prokaryotic Communities in Patagonian Lakes
From Current Microbiology: “The prokaryotic (microscopic single-celled organisms without a distinct nucleus with a membrane or other specialized organelles) abundance and diversity in three cold, oligotrophic Patagonian lakes (Témpanos, Las Torres and Mercedes) in the northern region Aysén (Chile) were compared in winter and summer…Prokaryotic abundances, numerically dominated by Bacteria, were quite similar in the three lakes, but higher in sediments than in waters, and they were also higher in summer than in winter… The prokaryotic community composition at Témpanos lake, located most northerly and closer to a glacier, greatly differed in respect to the other two lakes. In this lake was detected the highest bacterial diversity… Our results indicate that the proximity to the glacier and the seasonality shape the composition of the prokaryotic communities in these remote lakes. These results may be used as baseline information to follow the microbial community responses to potential global changes and to anthropogenic impacts.”
Read more about the results here.