Results 21 to 30 of about 312,748 (262)

Basal debris of the NEEM ice core, Greenland: a window into sub-ice-sheet geology, basal ice processes and ice-sheet oscillations

Journal of Glaciology, 2023
We present new data from the debris-rich basal ice layers of the NEEM ice core (NW Greenland). Using mineralogical observations, SEM imagery, geochemical data from silicates (meteoric 10Be, εNd, 87Sr/86Sr) and organic material (C/N, δ13C), we ...
Pierre-Henri Blard, Marie Protin, Jean-Louis Tison, François Fripiat, Dorthe Dahl-Jensen, Jørgen P. Steffensen, William C. Mahaney, Paul R. Bierman, Andrew J. Christ, Lee B. Corbett, Vinciane Debaille, Thomas Rigaudier, Philippe Claeys, ASTER Team   +13 more
doaj   +1 more source

A novel laser melting sampler for discrete, sub-centimeter depth-resolved analyses of stable water isotopes in ice cores

Journal of Glaciology, 2023
We developed a novel laser melting sampler (LMS) for ice cores to measure the stable water isotope ratios (δ18O and δD) as temperature proxies at sub-centimeter depth resolutions.
Yuko Motizuki, Yoichi Nakai, Kazuya Takahashi, Junya Hirose, Yu Vin Sahoo, Masaki Yumoto, Masayuki Maruyama, Michio Sakashita, Kiwamu Kase, Satoshi Wada, Hideaki Motoyama, Yasushige Yano   +11 more
doaj   +1 more source

Ice core hot-flid drilling

Antarctic Record, 1994
Fast hole production is possible using ice core hot-fluid drilling. The present paper describes a method for calculation of drill penetration rate dependent on the fluid flux, fluid temperature, physical properties of fluid, size of hot-fluid drill head ...
B.B. Kudryashov, N.G. Menshikov
doaj   +1 more source

Effects of ENSO on the major ion record of a Qomolangma (Mount Everest) ice core

Annals of Glaciology, 2016
Correlations between a 1000 year record of the major ions in a 108.83 m ice core from East Rongbuk Glacier (28°01’N, 86°58’E; 6518ma.s.l.) on the northeast slope of Qomolangma (Mount Everest) and the Southern Oscillation Index (SOI) were examined to ...
Hao Xu, Shugui Hou, Hongxi Pang, Chaomin Wang   +3 more
doaj   +1 more source

Initial results from geophysical surveys and shallow coring of the Northeast Greenland Ice Stream (NEGIS) [PDF]

The Cryosphere, 2014
The Northeast Greenland Ice Stream (NEGIS) is the sole interior Greenlandic ice stream. Fast flow initiates near the summit dome, and the ice stream terminates approximately 1000 km downstream in three large outlet glaciers that calve into the Greenland ...
P. Vallelonga, K. Christianson, R. B. Alley, S. Anandakrishnan, J. E. M. Christian, D. Dahl-Jensen, V. Gkinis, C. Holme, R. W. Jacobel, N. B. Karlsson, B. A. Keisling, S. Kipfstuhl, H. A. Kjær, M. E. L. Kristensen, A. Muto, L. E. Peters, T. Popp, K. L. Riverman, A. M. Svensson, C. Tibuleac, B. M. Vinther, Y. Weng, M. Winstrup   +22 more
doaj   +1 more source

Characterizing Spatial Variability of Ice Algal Chlorophyll a and Net Primary Production between Sea Ice Habitats Using Horizontal Profiling Platforms

Frontiers in Marine Science, 2017
Assessing the role of sea ice algal biomass and primary production for polar ecosystems remains challenging due to the strong spatio-temporal variability of sea ice algae.
Benjamin A. Lange, Benjamin A. Lange, Christian Katlein, Giulia Castellani, Mar Fernández-Méndez, Mar Fernández-Méndez, Marcel Nicolaus, Ilka Peeken, Ilka Peeken, Hauke Flores, Hauke Flores   +10 more
doaj   +1 more source

Agile Sub-Ice Geological (ASIG) Drill development and Pirrit Hills field project

Annals of Glaciology, 2021
A new drilling system was developed by the US Ice Drilling Program (IDP) to rapidly drill through overlying ice to collect subglacial rock cores. The Agile Sub-Ice Geological (ASIG) Drill system is capable of drilling up to 700 m of ice in a continuous ...
Tanner Kuhl, Chris Gibson, Jay Johnson, Grant Boeckmann, Elliot Moravec, Kristina Slawny   +5 more
doaj   +1 more source

Structural instability impairs function of the UDP‐xylose synthase 1 Ile181Asn variant associated with short‐stature genetic syndrome in humans

FEBS Letters, EarlyView.
The Ile181Asn variant of human UDP‐xylose synthase (hUXS1), associated with a short‐stature genetic syndrome, has previously been reported as inactive. Our findings demonstrate that Ile181Asn‐hUXS1 retains catalytic activity similar to the wild‐type but exhibits reduced stability, a looser oligomeric state, and an increased tendency to precipitate ...
Tuo Li, Pedro A. Sánchez‐Murcia, Bernd Nidetzky   +2 more
wiley   +1 more source

Seasonal evolution of granular and columnar sea ice pore microstructure and pore network connectivity

Journal of Glaciology, 2022
Sea-ice pore microstructure constrains ice transport properties, affecting fluid flow relevant to oil-in-ice transport and biogeochemical processes. Motivated by a lack of pore microstructural data, in particular for granular ice and across the seasonal ...
Marc Oggier, Hajo Eicken
doaj   +1 more source

The (Glg)ABCs of cyanobacteria: modelling of glycogen synthesis and functional divergence of glycogen synthases in Synechocystis sp. PCC 6803

FEBS Letters, EarlyView.
We reconstituted Synechocystis glycogen synthesis in vitro from purified enzymes and showed that two GlgA isoenzymes produce glycogen with different architectures: GlgA1 yields denser, highly branched glycogen, whereas GlgA2 synthesizes longer, less‐branched chains.
Kenric Lee, Dimitrios Bekiari, Sofia Doello, Karl Forchhammer   +3 more
wiley   +1 more source