Mycorrhizas and dark septate root endophytes in polar regions

German Literary Anthropology: Across Cultures, Across Genres Stefan Hermes and Sebastian Kaufmann, eds., Der ganze Mensch – die ganze Menschheit: Völkerkundliche Anthropologie, Literatur und Ästhetik um 1800 (Berlin: de Gruyter, 2014), 318 pp., 10 illustrations, €89.95What’s Old Is New Again, Mostly Julia Kuehn and Paul Smethurst, eds., New Directions in Travel Writing Studies (New York: Palgrave Macmillan, 2015), 325 pp., $90Complex Journeys around the World and through Literary and Intellectual Traditions around 1800 Johannes Görbert, Die Vertextung der Welt: Forschungsreisen als Literatur bei Georg Forster, Alexander von Humboldt und Adelbert von Chamisso. Weltliteraturen/World Literatures, Schriftenreihe der Friedrich Schlegel Graduiertenschule für literaturwissenschaftliche Studien, vol. 7 (Berlin: de Gruyter, 2014), vi, 426 pp., 8 illustrations, €109.95Travel as Cultural Work Gary Totten, African American Travel Narratives from Abroad: Mobility and Cultural Work in the Age of Jim Crow (Amherst: University of Massachusetts Press, 2015), 170 pp., $26.95Colonial Encounters between Africa and Europe—with Special Reference to Austria and Switzerland Manuel Menrath, ed., Afrika im Blick: Afrikabilder im deutschsprachigen Europa, 1870–1970 (Zurich: Chronos, 2012), 329 pp., €43Social Formations and Literary Forms in Long Nineteenth-Century Travel Writing Mary Henes and Brian H. Murray, eds., Travel Writing, Visual Culture and Form, 1760–1900 (London: Palgrave Macmillan, 2016), 248 pp., 21 illustrations, $95Travel Accounts of Polar Regions and Colonial Discourse Mike Frömel, Off ene Räume und gefährliche Reisen im Eis: Reisebeschreibungen über die Polarregionen und ein kolonialer Diskurs im 18. und frühen 19. Jahrhundert (Hannover: Wehrhahn, 2013), 288 pp., €29.50.“Imagined Geographies” and the Navigation of British European Identity Katarina Gephardt, Th e Idea of Europe in British Travel Narratives, 1789–1914 (Burlington, VT: Ashgate, 2014), 248 pp., 15 illustrations, $104.95Terminal and Threshold: Experiencing the Airport Christopher Schaberg, Th e End of Airports (London: Bloomsbury Academic, 2015), 216 pp., 25 illustrations, £13.99NOVEL REVIEW Finding Purity Jonathan Franzen, Purity (New York: Farrar, Straus and Giroux, 2015), 563 pp., $28

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On the Former Climate of the Polar Regions

The American Naturalist ◽

10.1086/271674 ◽

1876 ◽

Vol 10 (6) ◽

pp. 352-360

Author(s):

A. E. Nordenskiold

Keyword(s):

Polar Regions

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Enhanced Viral Activity in the Surface Microlayer of the Arctic and Antarctic Oceans

Microorganisms ◽

10.3390/microorganisms9020317 ◽

2021 ◽

Vol 9 (2) ◽

pp. 317

Author(s):

Dolors Vaqué ◽

Julia A. Boras ◽

Jesús Maria Arrieta ◽

Susana Agustí ◽

Carlos M. Duarte ◽

...

Keyword(s):

Environmental Factors ◽

Food Web ◽

Physicochemical Characteristics ◽

The Arctic ◽

Microbial Food Web ◽

Surface Microlayer ◽

Polar Regions ◽

Nutrient Inputs ◽

Viral Activity ◽

The Impact

The ocean surface microlayer (SML), with physicochemical characteristics different from those of subsurface waters (SSW), results in dense and active viral and microbial communities that may favor virus–host interactions. Conversely, wind speed and/or UV radiation could adversely affect virus infection. Furthermore, in polar regions, organic and inorganic nutrient inputs from melting ice may increase microbial activity in the SML. Since the role of viruses in the microbial food web of the SML is poorly understood in polar oceans, we aimed to study the impact of viruses on prokaryotic communities in the SML and in the SSW in Arctic and Antarctic waters. We hypothesized that a higher viral activity in the SML than in the SSW in both polar systems would be observed. We measured viral and prokaryote abundances, virus-mediated mortality on prokaryotes, heterotrophic and phototrophic nanoflagellate abundance, and environmental factors. In both polar zones, we found small differences in environmental factors between the SML and the SSW. In contrast, despite the adverse effect of wind, viral and prokaryote abundances and virus-mediated mortality on prokaryotes were higher in the SML than in the SSW. As a consequence, the higher carbon flux released by lysed cells in the SML than in the SSW would increase the pool of dissolved organic carbon (DOC) and be rapidly used by other prokaryotes to grow (the viral shunt). Thus, our results suggest that viral activity greatly contributes to the functioning of the microbial food web in the SML, which could influence the biogeochemical cycles of the water column.

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Effect of Ionizing Radiation on the Bacterial and Fungal Endophytes of the Halophytic Plant Kalidium schrenkianum

Microorganisms ◽

10.3390/microorganisms9051050 ◽

2021 ◽

Vol 9 (5) ◽

pp. 1050

Author(s):

Jing Zhu ◽

Xiang Sun ◽

Zhi-Dong Zhang ◽

Qi-Yong Tang ◽

Mei-Ying Gu ◽

...

Keyword(s):

Genetic Diversity ◽

Ionizing Radiation ◽

Endophytic Bacteria ◽

Fungal Endophytes ◽

Root Endophytes ◽

Fungal Community Structure ◽

Geochemical Factors ◽

Bacteria And Fungi ◽

High Level ◽

And Control

Endophytic bacteria and fungi colonize plants that grow in various types of terrestrial and aquatic ecosystems. Our study investigates the communities of endophytic bacteria and fungi of halophyte Kalidium schrenkianum growing in stressed habitats with ionizing radiation. The geochemical factors and radiation (at low, medium, high level and control) both affected the structure of endophytic communities. The bacterial class Actinobacteria and the fungal class Dothideomycetes predominated the endophytic communities of K. schrenkianum. Aerial tissues of K. schrenkianum had higher fungal diversity, while roots had higher bacterial diversity. Radiation had no significant effect on the abundance of bacterial classes. Soil pH, total nitrogen, and organic matter showed significant effects on the diversity of root endophytes. Radiation affected bacterial and fungal community structure in roots but not in aerial tissues, and had a strong effect on fungal co-occurrence networks. Overall, the genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments, however negative correlations were found between endophytic bacteria and fungi in the plant. The genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments. Our findings suggest that radiation affects root endophytes, and that the endophytes associated with aerial tissues and roots of K. schrenkianum follow different mechanisms for community assembly and different paradigms in stress response.

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Heat transfer in a two-phase closed thermosyphon working in Polar Regions

Thermal Science and Engineering Progress ◽

10.1016/j.tsep.2021.100846 ◽

2021 ◽

Vol 22 ◽

pp. 100846

Author(s):

G.V. Kuznetsov ◽

K.O. Ponomarev ◽

D.V. Feoktistov ◽

E.G. Orlova ◽

Yu.V. Lyulin ◽

...

Keyword(s):

Heat Transfer ◽

Polar Regions ◽

Two Phase

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Review on Applications of 17O in Hydrological Cycle

Molecules ◽

10.3390/molecules26154468 ◽

2021 ◽

Vol 26 (15) ◽

pp. 4468

Author(s):

Yalalt Nyamgerel ◽

Yeongcheol Han ◽

Minji Kim ◽

Dongchan Koh ◽

Jeonghoon Lee

Keyword(s):

Water Vapor ◽

General Circulation ◽

Hydrological Cycle ◽

General Circulation Models ◽

Convective Precipitation ◽

Subsurface Water ◽

Polar Regions ◽

Sea Ice Concentration ◽

Moisture Source ◽

Depositional Processes

The triple oxygen isotopes (16O, 17O, and 18O) are very useful in hydrological and climatological studies because of their sensitivity to environmental conditions. This review presents an overview of the published literature on the potential applications of 17O in hydrological studies. Dual-inlet isotope ratio mass spectrometry and laser absorption spectroscopy have been used to measure 17O, which provides information on atmospheric conditions at the moisture source and isotopic fractionations during transport and deposition processes. The variations of δ17O from the developed global meteoric water line, with a slope of 0.528, indicate the importance of regional or local effects on the 17O distribution. In polar regions, factors such as the supersaturation effect, intrusion of stratospheric vapor, post-depositional processes (local moisture recycling through sublimation), regional circulation patterns, sea ice concentration and local meteorological conditions determine the distribution of 17O-excess. Numerous studies have used these isotopes to detect the changes in the moisture source, mixing of different water vapor, evaporative loss in dry regions, re-evaporation of rain drops during warm precipitation and convective storms in low and mid-latitude waters. Owing to the large variation of the spatial scale of hydrological processes with their extent (i.e., whether the processes are local or regional), more studies based on isotopic composition of surface and subsurface water, convective precipitation, and water vapor, are required. In particular, in situ measurements are important for accurate simulations of atmospheric hydrological cycles by isotope-enabled general circulation models.

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