Bacterial diversity in tropical glacier and glacier foreland in Uganda : Glacier ecosystem influence soil formation in glacier foreland

第6回極域科学シンポジウム[OB] 極域生物圏11月16日（月）　国立極地研究所１階交流アトリウ

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Structural and geochimical analysis of basal ice from Taylor Glacier, Antarctica: on role and behaviour of the interstistial fluid phase

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Dynamic implications of discontinuous recrystallization in cold basal ice: Taylor Glacier, Antarctica

Crystallographic investigations have been conducted of cold (-17°C) debris-bearing ice from the base of an Antarctic outlet glacier (Taylor Glacier). The 4-m-thick sequence studied has been retrieved from a 20-m-long tunnel dug from the glacier snout and has been analyzed with an automatic ice fabric analyzer (AIFA). The top and bottom of the sequence consists of clean meteoric ice (englacial facies), whereas alternating debris-rich and clean bubbly ice layers are found in the middle part (stratified facies). Ice from the englacial facies displays a polygonal texture and a strong c-axis clustering toward the vertical, denoting recrystallization through "subgrain rotation" (SGR). In contrast, clean ice from the stratified facies shows SGR fabrics which are delimited at the contact with debris-rich layers by large, interlocking grains organized in ribbons. These two distinct textures within the stratified facies are associated with looser c-axis patterns at the scale of single thin sections, which is interpreted as resulting from "migration recrystallization" (MR). The change from SGR to MR trends marks a clear increase in grain boundary and nucleation kinetics (hence the term "discontinuous recrystallization") and may be associated with strain localization at rheological interfaces during basal ice genesis. Analogies with bottom ice from deep polar ice sheets, where temperature is commonly higher than at the studied site, are highlighted. Two recrystallization scenarios are proposed, accounting for the development of both types of fabrics. It is shown that by controlling the repartition of stress and strain energy within basal ice, the rheology of debris-bearing ice layers plays a decisive role in recrystallization dynamics at structural interfaces. We also demonstrate how the same recrystallization regimes may occur in cold glaciers and temperate ice sheets, provided that strain accumulation has been high enough in the former. This challenges the common belief that migration fabrics observed in bottom ice from deep ice sheets are exclusive to warm, stagnant, annealed ice. Copyright 2008 by the American Geophysical Union.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Strain-induced phase changes within cold basal ice from Taylor Glacier, Antarctica, indicated by textural and gas analyses

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Spatial Distribution of Unique Biological Communities and Their Control Over Surface Reflectivity of the Stanley Glacier, Uganda

Diverse microbes have been revealed to live in glaciers worldwide, but only a few biological studies were dedicated to glaciers in tropical Africa. These glaciers are shrinking rapidly and are expected to disappear shortly. In this study, we carried out biological and glaciological field observations on Stanley Glacier, the largest remaining glacier in the Rwenzori Mountains, Uganda, Africa. Microbial aggregates ranging from micrometer to centimeter in size were found on the glacier surface and contained moss and various types of Chlorophyta, among which a new endemic species of green alga. Concentrations of total impurities on the glacier surface, including microbial aggregates, varied spatially and decreased as altitude increased. The large microbial aggregates (larger than 4 cm in diameter) were found only at the glacier surface near the terminus and side margins, where the surface was less frequently covered with snow. It is also shown that the total organic matter on the glacier surface is determined by the timing of snow cover, which affects the quantity of solar radiation reaching the glacier ice surface. Furthermore, the total impurity content was negatively correlated with surface reflectivity, revealing their potential role in albedo reduction at the glacier surface through positive feedback between enhanced meltwater and increased biological growth

Equifinality of basal ice facies from an Antarctic cold-based glacier

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Dynamic recrystallization associated with gas composition changes in basal ice from an Antarctic glacier

info:eu-repo/semantics/publishe