Roundup: Oxygen Isotope, Non-biting Midges and Prokaryotes

Holocene Atmospheric Circulation in the Central North Pacific

From ScienceDirect: “The North Pacific is a zone of cyclogenesis [the development of an area of low pressure in the atmosphere, resulting in the formation of a cyclone] that modulates synoptic-scale atmospheric circulation. We present the first Holocene oxygen isotope record (δ18Odiatom) from the Aleutian Islands supported by diatom assemblage analysis. Our results demonstrate distinct shifts in the prevailing trajectory of storm systems that drove spatially heterogeneous patterns of moisture delivery and climate across the region.”

Read more about the new Holocene oxygen isotope record from the Aleutian Islands here.

A satellite picture of the Aleutian Island Range
Aerial view of the Aleutian Islands amidst the clouds (Source: NASA).

 

The Enigma of Survival Strategies in Glacial Stream Environments

From Freshwater Biology: “Glacier retreat is a key component of environmental change in alpine environments, leading to significant changes in glacier-fed rivers. The species compositions of Diamesinae and Orthocladiinae (of the non-biting midges family) are diverse and strongly affected by the changing habitat conditions upon glacier retreat. Here, we show that Diamesinae have extremely flexible feeding strategies that explain their abundance, high body-mass and predominance in glacier-fed streams.”

Discover more about the insects that live within the glacier-fed streams here.

Midge
A winter-emerging midge (Source: Flickr).

 

Phylogenetic Diversity of Prokaryotes on Lewis Glacier in Mount Kenya

From African Journal of Microbiology Research: “The seasonal snowpack of the temperate glaciers are sources of diverse microbial inoculi. However, the microbial ecology of the tropical glacial surfaces is endangered, hence posing an extinction threat to some populations of some microbes due to rapid loss of the glacier mass. The aim of this study was to isolate and phylogenetically characterise the prokaryotes from the seasonal snow of Lewis glacier in Mt. Kenya. Analyzing snow samples, the results confirm that the seasonal tropical snowpack of Lewis glacier is dominated by the general terrestrial prokaryotes (e.g. Bacillus with 53%) and a few glacier and snow specialist species (e.g. Cryobacterium with 5.9%).”

Find out more about these cellular organisms living on the surface of a Mount Kenya glacier here.

Cryobacterium
Cryobacterium (Source: Reddy et al.).

 

Please follow, share and like us:
error

Roundup: Karakoram, Dust and Prokaryotes

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.

Karakoram's glaciers were in a nearly balanced state between 1970-2010 (Source: mtzendo / Creative Commons)
Karakoram’s glaciers were in a nearly balanced state between 1970-2010 (Source: mtzendo/Creative Commons).

 

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.

An ice core from Taylor Glacier reveals changes in dust composition during the last deglaciation (Source: Oregon State University / Creative Commons).
An ice core from Taylor Glacier reveals changes in dust composition during the last deglaciation (Source: Oregon State University/Creative Commons).

 

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.

Prokaryotic diversity is greatest in Témpanos lake, near a glacier (Source: Cuorogrenata / Creative Commons)
Prokaryotic diversity is greatest in Témpanos lake, near a glacier (Source: Cuorogrenata/Creative Commons).
Please follow, share and like us:
error

Roundup: Fewer Hikers, Less Pollen, More Algae on Glaciers

Each week, we highlight three stories from the forefront of glacier news.

New Zealand Glaciers Banned Hiking

fox glacier new zealand gareth eyres Source: allcountries.org

From Mashable.com:

New Zealand is renowned for its wondrous scenery, and among the country’s top tourist attractions are two glaciers that are both stunning and unusual because they snake down from the mountains to a temperate rain forest, making them easy for people to walk up to and view.

The hot weather has even created a new type of tourist attraction over the other side of the mountains. Purdie said the glaciers there are also rapidly retreating, resulting in tourists taking boat rides on the lakes to see some of the massive icebergs that have begun to shear away.”

Read more about this policy here.

Microalgal Community Structures in Cryoconite Holes upon High-Arctic Glaciers of Svalbard

From Biogeosciences:

Biplot for the partial RDA with glacier and place as covariables, after interactive forward-selection covariates analysis. Source: photo of article.
Biplot for the partial RDA with glacier and place as
covariables, after interactive forward-selection covariates analysis. Source: Biogeosciences.

“Glaciers are known to harbor surprisingly complex ecosystems. On their surface, distinct cylindrical holes filled with meltwater and sediments are considered hot spots for microbial life. The present paper addresses possible biological interactions within the community of prokaryotic cyanobacteria and eukaryotic microalgae (microalgae) and relations to their potential grazers, such as tardigrades and rotifers, additional to their environmental controls. Svalbard glaciers with substantial allochthonous input of material from local sources reveal high microalgal densities.

Selective wind transport of Oscillatoriales via soil and dust particles is proposed to explain their dominance in cryoconites further away from the glacier margins. We propose that, for the studied glaciers, nutrient levels related to recycling of limiting nutrients are the main factor driving variation in the community structure of microalgae and grazers.”

Read more about microalgal community structures here.

Pollen Limitation in Nival Plants of European Central Alps

From American Journal of Botany:

Taxonomic composition of the pollen load of relevant insect pollinators ( N = 10 investigated individuals per insect group). Source: photo of article.
Taxonomic composition of the pollen load of relevant insect
pollinators ( N = 10 investigated individuals per insect group). Source: Am J Botany.

” A plant is considered to be pollen-limited when—due to an insufficient supply with pollen of adequate quality—the seed output remains below the potential value. Pollen limitation is thought to be a general phenomenon under the harsh climatic conditions at high latitudes and elevations.

Our study in the alpine–nival ecotone revealed that insect activity is not a limiting factor for pollination success in the studied plant species, which can be explained by the fact that anthesis functions and pollinator activity are largely coupled. ”

Learn more about pollen limitation here.

Please follow, share and like us:
error