Roundup: Meltwater Chemistry, Hydroelectric Dams and Glacier Elevation
Diurnal Changes in the Chemistry of Glacier Meltwater
From Chemosphere: “An evaluation of glacial meltwater chemistry is needed under recent dramatic glacier melting when water resources might be significantly impacted. This study investigated trace elements variation in the meltwater stream, and its related aquatic environmental information, at the Laohugou glacier basin (4260 m a.s.l.) at a remote location in northeast Tibetan Plateau… Results showed evident elements spatial difference on the glacier surface meltwater, as most of the elements showed increased concentration at the terminus compared to higher elevations sites… The accelerated diurnal and temporal snow-ice melting (with high runoff level) were correlated to increased elemental concentration, pH, EF (enrichment factor,the minimum factor by which the weight percent of mineral in is greater than the average occurrence of that mineral in the Earth’s crust) and elemental change mode, and thus this work is of great importance for evaluating the impacts of accelerated glacier melting to meltwater chemistry and downstream ecosystem in the northeast Tibetan Plateau.”
Locals Oppose Dam Construction in the North Western Himalayas
From the International Journal of Interdisciplinary and Multidisciplinary Studies: “Since early 1970s dam development projects witnessed severe opposition in India. The remote tribal groups and rural population rejected the idea of large scale displacement, land alienation, economic insecurity and endless suffering that came along with ‘development’ projects… In recent past the construction of hydroelectricity projects has faced severe opposition in the tribal regions in Himachal Pradesh. The locals in Kinnaur are facing numerous socio-economic and environmental consequences of these constructions in fragile Himalayan ecology… More than 30 hydro projects proposed in Lahaul & Spiti are also being challenged by the people in Chenab valley… The paper summarises the ongoing struggle and diverse implications added with climate change in the rural structures.”
Read more about local opposition to these projects here.
Uneven Changes in Ice Sheet Elevation in West Antarctica
From Geophysical Research Letters: “We combine measurements acquired by five satellite altimeter missions to obtain an uninterrupted record of ice sheet elevation change over the Amundsen Sea Embayment, West Antarctica, since 1992… Surface lowering has spread slowest (<6 km/yr) along the Pope, Smith, and Kohler (PSK) Glaciers, due to their small extent. Pine Island Glacier (PIG) is characterized by a continuous inland spreading of surface lowering, notably fast at rates of 13 to 15 km/yr along tributaries draining the southeastern lobe, possibly due to basal conditions or tributary geometry… Ice-dynamical imbalance across the sector has therefore been uneven during the satellite record.”
Read more about the changes in ice sheet elevation here.
A calving event in Porcupine Glacier shows rapid retreat
From the American Geophysical Union: “Porcupine Glacier is a 20 km long outlet glacier of an icefield in the Hoodoo Mountains of Northern British Columbia that terminates in an expanding proglacial lake. During 2016 the glacier had a 1.2 square kilometer iceberg break off, leading to a retreat of 1.7 km in one year. This is an unusually large iceberg to calve off in a proglacial lake, the largest ever seen in British Columbia or Alaska… The retreat of this glacier is similar to a number of other glaciers in the area: Great Glacier, Chickamin Glacier, South Sawyer Glacier and Bromley Glacier. The retreat is driven by an increase in snowline/equilibrium line elevations which in 2016 is at 1700 m, similar to that on South Sawyer Glacier in 2016.”
Learn more about the retreat of Porcupine glacier, and view satellite images here.
Patterned ground exposed by glacier retreat in the Alps
From the Biology and Fertility of Soils: “Patterned ground (PG) is one of the most evident expressions of cryogenic processes affecting periglacial soils, where macroscopic, repeated variations in soil morphology seem to be associated with small-scale edaphic [impacted by soil] and vegetation gradients, potentially influencing also microbial communities. While for high-latitude environments only few studies on PG microbiology are available, the alpine context, where PG features are rarer, is almost unexplored under this point of view… These first results support the hypothesis that microbial ecology in alpine, periglacial ecosystems is driven by a complex series of environmental factors, such as lithology [study of the general physical characteristics of rocks], altitude, and cryogenic activity, acting simultaneously on community shaping both in terms of diversity and abundance.”
Learn more about glacier retreat in the Italian Alps here.
Microorganisms found in glacial meltwater streams
From Polar Biology: “Microbial communities living in microbial mats are known to constitute early indicators of ecosystem disturbance, but little is known about their response to environmental factors in the Antarctic. This paper presents the first major study on ciliates [single-celled animals bearing cilia] from microbial mats in streams on King George Island (Antarctica)… Samples of microbial mats for ciliate analysis were collected from three streams fed by Ecology Glacier. The species richness, abundance, and biomass of ciliates differed significantly between the stations studied, with the lowest numbers in the middle course of the stream and the highest numbers in the microhabitats closest to the glacier and at the site where the stream empties into the pond. Variables that significantly explained the variance in ciliate communities in the transects investigated were total organic carbon, total nitrogen, temperature, dissolved oxygen, and conductivity.”