bluuebunny/crossref_metadata_2025 huggingface dataset:
Freeze‐thaw activity and some of its geomorphic implications in the abisko mountains, Swedish Lappland
Authors: Nyberg Rolf
Published: February 2007

Freeze‐thaw activity was studied at two mountain sites in Swedish Lappland, a debris‐mantled slope with small rockwalls at 1200 m altitude and a solifluction slope at 1050 m altitude. During the snow‐free period, there was a low intensity of short‐term frost cycles at the rockwall site, implying that current frost shattering of bedrock is mainly due to the annual freeze cycle. At the solifluction site, during a period with net surficial soil movements of up to 3 cm, short‐term frost cycles were absent below 0.1 m depth in the ground, suggesting a dominance of pure solifluction over frost creep. A considerable variability in near‐ground temperatures implies that in situ measurements, rather than meteorological screen data, are essential in assessments of frost action in high mountain terrain.
An approach to determine the origin and age of massive ice blockages in two arctic caves
Authors: Lauriol Bernard , Clark Ian D.
Published: February 2007

Massive ice formations found blocking karst cave passages in alpine and permafrost regions are not uncommon, although their origin and age are not readily apparent. With two examples from northern Yukon, we present an approach to elucidate the mode of formation, using stable isotopes, ice fabric and the time of formation by the radiocarbon activity of cryogenic powder found in such ice. These data are supported by 14C dates on associated animal and plant remains.

Ice formation is sensitive to seasonal air circulation patterns, with condensation from warm humid air flowing inward along the cave roof in summer, and sublimation by cold dry air penetrating along the cave floor in winter. Massive ice blocking the two caves is shown to form by gradual accumulation of floor ice from below, and accretion of hexagonal ice growing down from the cave roof.
Determination of pollen accumulation rates in frozen sediments
Authors: Wang Xia‐Cheng , Geurts Marie‐Anne
Published: February 2007

Pollen accumulation rates (PAR) of 48 samples from a permafrost core were calibrated to assess the influence of ice lensing on the calculations. Results show that permafrost formation can radically change PAR values. Accumulation of segregated ice is a major source of error, while the 9% volumetric expansion of pore water upon freezing must also be considered. The basic result of these influences is the exaggeration of sedimentation rates and sample volumes.
Climate and permafrost
Authors: Gavrilova M. K.
Published: February 2007

Data from Yakutia, Siberia, indicate that permafrost has been generally stable for the last 300,000 years. Historic records indicate climatic variability in the last 150 years and predict that, in comparison with the 1980s, winters will be colder and summers warmer in the early part of the twenty‐first century. Predicted man‐induced climate warming, superimposed upon these natural trends, will offset the winter cooling, while summers will be even warmer. Changes in mean annual air temperatures for the mid twenty‐first century are calculated as being half the sum of the winter and summer temperature changes. Permafrost will be preserved in mountainous regions and in the eastern polar and subarctic plains. In western Siberia and subarctic eastern and southern Siberia considerable permafrost thawing will occur and near‐surface ground temperatures will rise.
Thermokarst involutions, summer island, pleistocene mackenzie delta, Western Canadian arctic
Authors: Murton Julian B. , French Hugh M.
Published: February 2007

Thermokarst involutions form primarily by loading, buoyancy and water‐escape during the degradation of ice‐rich permafrost. In the Summer Island area of the Pleistocene Mackenzie Delta, they are formed mainly by loading and buoyancy, and occur within a Late Wisconsinan‐Early Holocene thaw layer. Involutions formed by water‐escape (fluidization) occur within slump‐floor deposits.

To form thermokarst involutions, ice‐rich permafrost must thaw, drainage conditions must be poor and sediments must vary in texture or composition. In addition, the sediments should be susceptible to fluidization, liquefaction or hydroplastic deformation. Thermokarst involutions formed by loading and buoyancy require a reverse density gradient; those formed by fluidization require open‐system groundwater conditions or associated water‐saturated sediments susceptible to liquefaction.
Rock moisture data from Livingston Island (maritime antarctic) and implications for weathering processes
Authors: Hall Kevin
Published: February 2007

Rock moisture content was determined for rock samples on different aspects of rock outcrops on Livingston Island during a summer season. As a result of the dominant rainbearing northerly winds the southern aspect usually has rock moisture levels lower than the northern. The southern aspect, however, experiences high rock moisture levels during periods of snowmelt; snow accumulates on the southern, lee‐side of the rock outcrops. Wetting and drying events are more frequent on the northern exposure, although not as common as at a site open through the full 360°, while the southern aspect tends to experience continuous, low moisture levels with infrequent dry events. Contrary to earlier suggestions, freeze–thaw weathering does not appear to be a major factor during the summer. Although rock moisture levels are conducive to freeze–thaw, rock temperatures rarely go below 0°C. Rather, it appears that weathering due to wetting and drying may be more common on the northern aspects than was previously thought while chemical weathering is active on southerly aspects. Rock moisture levels may support rock damage due to segregation ice during the winter freeze when the rate of freezing is slowed by the overlying snow cover.

Contrairement a ce qui a été suggéré précédemment, l'altération par gel‐dégel ne semble pas ětre, l'été, un facteur de désagrégation principal. Quoique les niveaux d'humidité soient favorables aux actions de gel‐dégel, les températures des roches y descendent rarement sous 0°C. Au contraire, il apparaǐt que l'altération due aux alternances sèchage / humidification doit ětre plus fréquente sur les versants exposés au nord, tandis que l'altération chimique serait surtout active sur les versants exposés au sud. Les niveaux d'humidité des roches peuvent engendrer une désagrégation due à la formation de glace de ségrégation pendant l'hiver parce que la vitesse de gel est ralentie par la couverture de neige.
Devensian thermal contraction networks and cracks at Somersham, Cambridgeshire, UK
Authors: West R. G.
Published: February 2007

Middle and Late Devensian thermal contraction networks and cracks are described from the southern Fenland, Cambridgeshire. They are associated with gravel aggradations of low terraces of the River Great Ouse. Two networks are described, one set younger than the other. Three types of contraction crack are described. Type 1 occurs within the gravel aggradation of a c. 3 m OD terrace; type 2 penetrates this gravel and is filled with a complex of sediments, including primary, secondary and trough fillings; type 3 penetrates younger lacustrine sediments and gravels associated with Lake Sparks, the lake formed by the damming of Fenland by Late Devensian ice at the Wash. The networks are related to type 2 and type 3 cracks. The relation of permafrost periods to the stratigraphy and landscape development is described, together with the chronology. Periods of sand‐loess and cover sand deposition are identified. A period of permafrost degradation may be associated with change of climate and/or the development and proximity of Lake Sparks. A major period of permafrost in the area is correlated with the Weichselian Late Pleniglacial major permafrost event in the Netherlands (24 ka to 17 ka BP) and a similar major event in Poland (22 ka to 19/20 ka BP). This appears to be, broadly, the period leading up to and associated with the advance of the Late Devensian (Weichselian) ice in Britain and on the continent.
Caractéristiques de la Cinétique de Congélation de Sols Salins
Authors: Frolov A. D. , Seguin M.‐K.
Published: February 2007

Nous présentons l'analyse des résultats d'une étude expérimentale réalisée à l'aide des méthodes de spectroscopie diélectrique et de conversion électroacoustique. Ces expériences ont été effectuées sur des modèles de sable de quartz poreux saturé de solutions de concentration différente, à contenu ionique différent et gelé. Ces expériences ont permis d'établir les particularitées communes à la cinétique de congélation de sols salins. Il s'est avéré que la concentration limite des solutions saturantes dans les pores est d'environ 10−2 mole 1−1. Cette limite correspond à la concentration a partir de laquelle la cinétique de congélation de sols salins diffère substantiellement de celle de sols non‐salins. Pour des concentrations de solutions dans les pores qui sont >10−2 mole 1−1, le sable gelé conserve sa perméabilité (dans les pores et capillaires) jusqu'à des temperatures très basses. On démontre que lors du processus de congélation, le changement du contenu de la phase liquide s'effectue en měme temps que le degré de discrétisation (ségrégation et fractionation) volumique et la mobilité des ions augmentent. La modification d'un sol gelé fortement salin (>10−1 mole 1−1) en un sol gelé non‐salin s'effectue à des températures environ 10 K plus basses que les eutectiques pour le composé ionique d'une solution spécifique.
Origin of permafrost lake deposits in the Central Andes
Authors: Gorbunov A. P.
Published: February 2007

Perennially frozen lacustrine deposits in the Bolivian Altiplano are discussed. They are situated between 21°38′S and 23°13′S at an elevation of 4117–4730 m ASL. It is hypothesized that these ice‐rich lacustrine deposits formed as the result of subaquatic freezing of sediments in the Late Pleistocene to Early Holocene. The permafrost bodies are represented today by flat‐topped ridges and mounds which are the remnants of the original lake plains destroyed by thermokarst processes.
Permafrost distribution and rock glaciers in the livigno area (Northern Italy)
Authors: Guglielmin M. , Lozej A. , Tellini C.
Published: February 2007

Geophysical investigations were undertaken in the Livigno area (Sondrio, northern Italy) during 1991–92 at a number of sites where permafrost had been suggested through the application of other techniques, such as geomorphological studies, measurements of bottom temperature of winter snow cover (BTS), measurement of ground temperature in summertime (STG), and temperature of spring waters. Geoelectrical surveys confirm and characterize these permafrost occurrences. Furthermore, they indicate that, outside the rock glaciers, permafrost is also present in some gelifluction lobes. The permafrost bodies differ with regard to parameters such as resistivity, depth and thickness. Resistivity ranges from 18,000 to 560,000 ωm (ohm metres), depth varies between 8 and 21.1 m, and the active layer is 2 to 4.7 m thick in those bodies that can be considered active on the basis of morphological features.
Streamflow processes in an alpine permafrost catchment, tianshan, China
Authors: Woo Ming‐Ko , Yang Zhenniang , Xia Zhaojun , Yang Daqing
Published: February 2007

The Cirque Basin, Tianshan, China is characterized by steep slopes, coarse surficial deposits and a cold climate that maintains permafrost at shallow depths. These conditions exert strong influences on the streamflow processes. In late winter, freezing of the infiltrated meltwater from an uneven snow cover enables ground ice formation. This renders parts of the active layer impervious to seepage, and in the spring both surface and subsurface flows can occur to supply water to the stream. In summer, the coarse materials facilitate rapid infiltration and exfiltration. Where the channel slope is steep, as in the upper basin, infiltration results in a dry stream bed but deep percolation is prevented by a shallow frost table. Exfiltration prevails in the lower basin where the channel gradient is reduced, and streamflow increases rapidly within half a kilometre, from zero to its maximum values at the gauging station. Water balance analysis yields a high runoff ratio of 0.75 for this basin and this is comparable with other tundra areas. The streamflow processes observed in this basin should be applicable to other non‐polar alpine catchments.
Climate controls and high‐altitude permafrost, qinghai‐xizang (tibet) Plateau, China
Authors: Wang Baolai , French Hugh M.
Published: February 2007

The high altitude‐induced permafrost of the Tibet Plateau reflects a geothermal regime characterized by a strong diurnal pattern, high solar radiation inputs at the surface, and a high geothermal gradient. As a result, the permafrost is relatively [warm] and sensitive to thermal disturbance. Typical permafrost‐related processes, such as ice segregation and thermal contraction cracking, are not widespread, and patterned ground phenomena (circles and nets) are restricted to sites of locally high moisture and variable grain size. Ice‐rich sediments on north‐facing slopes occur mainly as silty colluviums derived from local argillaceous bedrock. Mean annual ground temperatures are usually warmer than −3.5°C. Temperatures at 20 m depth have increased by an average of 0.2 to 0.3°C during the past 15 years. If one assumes continued warming, permafrost is likely to become relict within the next 200 years, and an increase in degradation (i.e. thermokarst processes) is to be expected.
Current changes of climate and permafrost in the arctic and sub‐arctic of Russia
Authors: Pavlov A. V.
Published: February 2007

In northern Russia, from the time meteorological measurements began in the early nineteenth century to the end of that century, the air temperature was characterized by a general decrease (approximately 1°C). It then rose up to the 1950s (by 0.6°C). A subsequent slight fall in temperature lasted until the mid 1970s. Since then a further rise has been observed (0.6–0.9°C). Temperatures in the upper horizons of permafrost over the last 10–20 years are in good agreement with recent global warming trends. For the European north‐east during the period 1970–90 a rise in temperature at a depth of 3 m amounted to 0.6–0.7°C on average. However, this rise is related not necessarily to a rise in air temperature, but more likely to an increase in snow cover.
Thufur in the mohlesi valley, lesotho, Southern Africa
Authors: Grab S. W.
Published: February 2007

Although a considerable amount of periglacial work has concentrated on thufur found in polar and subpolar regions, information pertaining to those in other areas, especially the alpine regions of Africa, is extremely limited. Field observations and measurements provide empirical information on their external and internal morphology in an alpine region of Lesotho, southern Africa. Animal activity, wind action, the effects of surface water and/or ice, and the influence of needle ice are factors which cause thufa breakup. Some thufur in the Mohlesi valley are inactive while others are periodically active under present climatic conditions.
Ice‐wedge rejuvenation, fosheim peninsula, ellesmere Island, Canada
Authors: Lewkowicz Antoni G.
Published: February 2007

Ice wedges with multiple growth stages and complex wedge systems are described for six sites on the Fosheim Peninsula. Recent rates of lateral wedge growth, inferred from tritium concentrations within the ice, are 2–5 mm a−1. One factor responsible for ice wedge rejuvenation in this area is colluviation on low‐angled slope segments by slopewash, solifluction and active‐layer detachment processes or by mudflow within retrogressive thaw slumps. The most complex section examined was at the base of a long slope where colluvial deposits overlay peat. Epigenetic and syngenetic wedges of at least two and possibly three different ages were present as a result of sedimentation rates estimated to be 4–25 mm a−1.

The second factor producing wedge rejuvenation is variability in summer climate, and this is responsible for the development of the uppermost growth stages at all actively cracking sites. The deepest thaws in the past 45 years were hind‐cast for 1960 and 1962 so that more than 25 years of aggradation had taken place by the time of fieldwork. More generally, it can be shown that there is a significant probability that secondary wedges will be present during any period without regional climatic change. For the Eureka summer climate, the probability is 0.2 that a secondary wedge at least 5 cm high and 10 years old will be observed at any randomly exposed section. Thus field observation of widespread secondary growth stages is not necessarily an indication of recent climatic change but may be due to normal climatic variability.
Ice‐wedge casts and relict polygonal patterned ground in North‐East Iowa, USA
Authors: Walters James C.
Published: February 2007

Sediment‐filled wedges and associated polygonal patterned ground occur in pre‐Illinoian sediments in north‐east Iowa. A total of 183 vertical to near‐vertical wedge‐shaped bodies of sand have been observed at 12 sites in Black Hawk County, Iowa, and 80 of them were examined in detail. The wedges average 105cm in width at their tops and about 190cm in depth. Infilling material is mostly sand, with pockets of silt, silty sand, and gravelly sand. Slump and subsidence features were also noted in some wedges. Loamy sediment about 1 m thick, with a stone line at its base, overlies the sediment‐filled wedges and usually descends slightly into their upper parts.

Based on their characteristics, these sediment‐filled wedges are interpreted as ice‐wedge casts. Supportive palaeoenvironmental studies in Iowa and adjacent states indicate that tundra conditions probably existed in places between 21,000 and 16,500 years BP, the coldest part of late Wisconsinan time. Mean annual air temperatures at this time may have been at least 14°C colder than at present. The degradation of permafrost and formation of ice‐wedge casts must have occurred near the end of this episode of cold climate, which also promoted extreme erosion of the landscape in north‐east Iowa. Aeolian and slopewash deposits later buried the erosion surface and the ice‐wedge casts.
Permafrost in china: Past and present
Authors: Guoqing Qiu , Guodong Cheng
Published: February 2007

Permafrost regions occupy some 2,150,000 km2 or 22.4% of the territory of China. The distribution characteristics are closely related to variations in climatic conditions. The permafrost area has changed since the Late Pleistocene. In north‐eastern China, the southern limit of permafrost extended to latitude 41‐42.N during the coldest stage of the Last Glaciation; in the Holocene Megathermal the southern limit retreated northwards. But the ice‐wedges and permafrost that formed in the Late Pleistocene are still present in the northern part of Mt Da‐Hingganling. The finding of inactive ice‐wedges at Yitulihe indicates a colder climate and an enlargement of permafrost during the Late Holocene. With these climate changes, the lower limit of high‐altitude permafrost in the alpine and plateau regions of western China moved up 800‐1000 m, but most of the high mountains and plateaux still remain periglacial.
Suprapermafrost groundwater seepage in gravelly terrain, resolute, NWT, Canada
Authors: Woo Ming‐Ko , Xia Zhaojun
Published: February 2007

Gravel terrain in the polar desert region of Arctic Canada supports many features such as saturated zones, wetlands, ponds and streams, all of which are associated with local seepage of suprapermafrost groundwater. Gravels have high specific yield and large hydraulic conductivity to facilitate water flow, but a shallow frost table prevents deep percolation so that, given adequate water supply from snowmelt or rainfall, seepage will occur where the topographic surface intersects the water table. Such seepage can be seen on concave slopes to produce local saturated zones. Where seepage is focused, wetlands, ponds and small streams are maintained. Water balance computation for a wetland and a pond shows that seepage from their upslope gravel zones is a major water source. Continual seepage alters the soil, vegetation and moisture characteristics of the site, and the resulting thermal and hydrological feedbacks perpetuate the various features discussed.
Mountain permafrost and slope instability in the Italian Alps: The Val Pola Landslide
Authors: Dramis F. , Govi M. , Guglielmin M. , Mortara G.
Published: February 2007

In July 1987 a landslide affected the Val Pola (Central Alps, Italy) causing several casualities and severe damage. The main conditioning and triggering factors for the huge debris avalanche are described and possible mechanisms are suggested. Present‐day high‐mountain periglacial conditions (such as rock glaciers) present in the area highlight the probable role played by the presence of mountain permafrost in triggering the slope instability.
Quelques Coupes Caractéristiques dans les Dépǒts de Versant d'Aquitaine Septentrionale: Fades et Interprétation Dynamique
Authors: Ozouf J.‐C. , Texier J.‐P. , Bertran P. , Coutard J.‐P.
Published: February 2007

Les auteurs présentent et discutent quelques coupes caractéristiques des dépǒts de versant d'Aquitaine septentrionale. A l'ouest de la région, dans les Charentes, s'observent principalement des grèzes litèes liées au fonctionnement de nappes coulées de solifluxion. Plus à l'est, en Périgord, ce type de dépǒt est très rare. En revanche, les faciés y sont beaucoup plus diversifiés et réultent de processus variés: coulées de solifluxion à front pierreux, coulées de solifluxion ‘en blocs’ ou sous pelouse, éboulis gravitaires, coulées sèches, flots de débris, flots de boue. Ces différences s'expliquent principalement par une plus grande diversité des roches mères et un relief plus vigoureux en Périgord.
The Lorraine Grèzes Litées Deposits
Authors: Deshaies M. , Ghanini S. , Harmand D. , Weisrock A.
Published: February 2007

Des dépǒts stratifiés de grèzes litées sont décrits dans des sites voisins de Tilly‐sur‐Meuse et Domrémy‐la‐Pucelle. Les matériaux proviennent du substratum local. Il y a un déficit de fines dans ces formations et le ruissellement est considéré comme le processus de dépǒt le plus probable.
Le litage des Éboulis Stratifiés Cryonivaux en Gaspésie (Québec, Canada): Rǒle de la Sédimentation Nivéo‐Éolienne et des Transits Supranivaux
Authors: Hétu Bernard
Published: February 2007

Des cõnes d'éboulis stratifiés cryonivaux évoluent actuellement, sous climat tempéré froid, dans des enclaves de l'étage forestier gaspésien (Québec, Canada). Un suivi des processus a permis d'identifier les étapes de la stratogenèse. Les principaux aspects examinés sont: (a) le rǒle respectif des processus impliqués dans la stratogenèse, en particulier les processus de remaniement syn/épigénétiques; (b) la caractérisation de la signature sédimentaire propre à chacun des processus. Elle permet leur identification en coupe. Seule la partie inférieure des cǒnes d'éboulis est clairement stratifiée. Les coupes alternent quatre types de lits: (1) des couches de fines plaquettes d'argilite (de la taille des grèzes) qui se déplacent par saltation à la surface du manteau nival lors des blizzards; (2) des couches de sables moyens à grossiers dérivant des manteaux nivéo‐éoliens associés aux vents d'intensité modérée; (3) des couches openwork constituées de grosses plaquettes imbriquées résultant de glissements supranivaux; (4) des couches diamictiques qui correspondent à des laves boueuses supranivales. Il n'y a aucune périodicité saisonnière stricte dans la mise en place des lits. Comme la plupart des transferts de débris se font sur la neige, la majorité des caractéristiques de faciès observées dans les coupes sont acquises lors de la fonte des neiges, auxquelles s'ajoutent les effets de la reptation, du splash et des percolations de saison chaude. Que ces éboulis stratifiés évoluent actuellement dans une région tempérée forestière montrent que des conditions périglaciaires rigoureuses ne sont pas nécessaires à leur développement.
Recent climatic trend and thermal response of permafrost in Salluit, Northern Quebec, Canada
Authors: Wang Baolai , Allard Michel
Published: February 2007

Not all places may in fact warm under global change scenarios. This paper presents an example of climatic cooling from northern Quebec, Canada. Ground temperature measurements along the southern shore of Hudson Strait, northern Quebec indicate a cooling trend over the last seven years (1987‐93). Long‐term air temperature records show that this area has actually experienced continuous cooling for more than 40 years. Related studies suggest that the cooling is likely to continue due to freshening of subpolar water in the North Atlantic and Labrador Sea area. A one‐dimensional geothermal model was used to simulate the effect of continued cooling on permafrost thermal regime in Salluit, northern Quebec. The results show that, if the climatic trend continues for the next 50 years, the thickness of the active layer would decrease by 30cm (from 2.3 to 2.0 m) in gneiss and by 20cm (from 1.3 to 1.1 m) in till. Permafrost temperature at 20 m depth would decrease by 0.65 °C. Under the cooling scenario, rate of permafrost creep and slope activities would be reduced. Ice‐wedge regrowth would continue, and the buried ice wedges may even become reactivated. The results also indicate that regional snow precipitation data cannot be used directly in predicting ground thermal regimes.
The chronology of upper pleistocene stratified slope‐waste deposits in central Italy
Authors: Coltorti M. , Dramis F.
Published: February 2007

Stratified slope‐waste deposits are widespread in central Italy, even at elevations close to the present coastline. They are evidence of the cold climatic conditions which affected the area during the cold stages of the Upper Pleistocene. Their occurrence was strongly influenced by bedrock lithology (they are common on slopes composed of micritic and marly limestone). Detailed morphostratigraphic analysis and 14C dating of alluvial and inter‐fingered slope‐waste deposits in a mountain area of the Umbria‐Marche Apennine (Upper Esino River basin) allows an outline of the chronological sequence of debris depositional phases during the Late Pleistocene. A few dates were also obtained from the Ponte di Crispiero sequence (in the contiguous Potenza River basin), which may be considered as a type section for the Late Pleistocene of Central Italy, Adriatic side. The stratified slope‐waste deposits were deposited after 50,000 to 60,000 years BP, in the Stadials of the Middle and Upper Pleniglacial. During the Interstadials, most of the slopes of the basin were colonized by steppe vegetation and the production of stratified debris was probaby restricted to the highest elevations. Increased rates of debris deposition occurred during the Upper Pleniglacial.
Microbial life in permafrost: A historical review
Authors: Gilichinsky D. , Wagener S.
Published: February 2007

This paper reviews the literature on cold‐adapted micro‐organisms which might exist in ice and permafrost. Properly identified, microbial markers in the cryolithozone could be used in palaeoenvironmental reconstructions, in distinguishing between epigenetic and syngenetic depositional sequences, and in the recognition of secondary thaw unconformities. Cryobiological problems include (1) whether the bacteria are dead, dormant or in the active state, and (2) what factors determine the preservation of cell structures. A possible consequence of permafrost thawing, based upon predicted global warming scenarios, is that there may be an increase in microbial activity and an increase in active layer thickness.
A note on rock glaciers in the Albanian Alps
Authors: Palmentola G. , Baboci K. , Gruda G. J. , Zito G.
Published: February 2007

In the Albanian Alps, above 1700 m a.s.1., sixteen inactive rock glaciers have been identified, all colonized by herbaceous vegetation. Assuming a −2°C isotherm for the activity of rock glaciers, and after calculating the atmospheric lapse rate, it is estimated that thermal conditions must have been 6.4°C lower than the present mean annual temperature. Because rock glaciers occupied surfaces covered by ice during the periglacial Würm period, they cannot be older than 14,000‐17,000 years; so they are probably referable to the Dryas. Such a temperature drop took place probably during the Dryas.
Gelifluction in the alpine periglacial environment of the Tianshan Mountains, China
Authors: Gengnian Liu , Heigang Xiong , Zhijiu Cui
Published: February 2007

Gelifluction in the periglacial zone of the Tianshan Mountains occurs at 2500‐3600 m above sea level on north‐facing slopes. Abundant groundwater, fine grained sediments and slopes 10°‐30° favour gelifluction. Most gelifluction forms are lobate, a few are tongue‐shaped. The mean surface rate of movement is 11.14cm/a; the front advancing rate is 1.86cm/a. The moving rate in the middle part is greater than at the sides of gelifluction lobes, the mean rates being 3.1 cm/a and 0.86cm/a, respectively.
Permafrost microbiology
Authors: Gilichinsky D. A. , Wagener S. , Vishnevetskaya T. A.
Published: February 2007

Numerous and various ecological and morphological groups of viable micro‐organisms survive under permafrost conditions. They are the only known living organisms preserved over a geologically significant time. Their preservation within permafrost is of interest from both biological and geocryological points of view and forms the basis for a number of investigations in different scientific fields. The latter are performed not only upon morphological but also upon functional characteristics of viable cells. This approach is relevant to questions concerning the protective properties of unfrozen water and may provide new ways of solving major problems of historical geocryology. Of special interest is the interaction of both biological and geological knowledge to better understand the spatial and temporal limits of the biosphere.
The geochemical paradox of ice‐complex sediments in north Siberia
Authors: Konishchev V. N. , Plakht I. R.
Published: February 2007

Icy silty deposits in northern Siberia, here termed ‘ice‐complex sediments’ (ICS), have a higher salinization than other continental deposits of Neogene‐Pleistocene age. Data for salinity (%) and the ratio of Ca ion content to Cl ion content for samples from the Yana‐Indigirskaya and Kolymskaya lowlands indicate that the salinization of Pleistocene permafrost is lowest, that icy silts have salinities between 0.1% and 1.0%, and that recent floodplain, coastal and alas deposits have salinities greater than 1%. These differences are thought to reflect the phase change in gas‐liquid inclusions in crystals and rocks when they break and their contents (solutions) are released during freezing. This process is termed cryocryptogenesis. It is concluded that ICS deposits were formed under less humid and colder conditions than exist today in northern Yakutia, but more humid than central Yakutia.
Observations on nearshore pingo growth, Adventdalen, Spitsbergen
Authors: Yoshikawa Kenji , Harada Koichiro
Published: February 2007

The open‐system pingos of Svalbard can be divided into three groups. Group I pingos are located over geologic faults. Group II pingos are located in areas of artesian flow resulting from the migration of sub‐glacial groundwater. Pingos of group II occur usually in riverbeds, where the permafrost is locally thinner. Group III pingos are located in nearshore or low‐lying environments of active geologic uplift, where groundwater flow is in response to relict conditions. In this paper group III pingos in the Adventdalen delta area are examined. Group III pingos characteristically have a complex shape and occur in groups. Growth occurs rapidly after initial emergence from marine conditions and the establishment of a minimum permafrost thickness. Water is supplied through discontinuities in the aggrading permafrost. Net influx of water is moderate, owing to relatively thin permafrost.
A field survey of late‐summer depths to frozen ground at two study areas near mayo, Yukon Territory, Canada
Authors: Leverington David
Published: February 2007

A field survey of late‐summer depths to frozen ground within 1.5 m of ground surface was performed in July and August of 1994, in support of the Cryospheric System programme of the Earth Observing System. This project's stratified sampling technique was devised to be a simple and efficient means to sample a very large number of sites over two areas of interest, within a relatively short period. The successful completion of the 1994 field season resulted in the compilation of a large and representative dataset of depths to frozen ground near Mayo, Yukon Territory. The survey suggests that most late‐summer depths to frozen ground cluster within a narrow depth range in the main study area, while a much smaller proportion of this study area's dataset extends deeper to the 1.5 m depth limit of this study. Furthermore, the results of the survey suggest that considerable differences can exist between closely spaced study areas with regard to predominant depths to frozen ground, as well as relations between surface variables and depths to frozen ground. This implies that computer‐based models designed to map active layer thicknesses through correlation with landcover and topographic imagery must be supported by field measurements made in all areas being mapped. The extrapolation of correlations measured between active layer conditions and surface variables from one study area to an unsurveyed study area cannot be assumed to be valid. The mapping of active layer thickness over large regions (e.g. central Yukon) will therefore require a considerable field effort if reliable correlative mapping products are to be generated.
Development of a hazardous material compatibility storage guideline and tool
Authors: Moder Kenneth P. , Russo John P. , Justiniano Francisco , Marshall William F. , Mcghee Thomas H. , Stankovich Robert , Frank W.L.
Published: February 2007

A hazardous material compatibility storage guideline and an abbreviated hazardous material compatibility storage tool, both consistent with center for chemical process safety (CCPS) guidance for managing chemical reactivity hazards, were developed for sites storing reactive materials.

The hazardous material compatibility storage tool assists personnel in developing and documenting appropriate storage strategies. The tool identifies potential hazardous combinations of materials for material handlers and suggests storage strategies that minimize the risk of such combinations. This tool is formatted as a template and is adaptable to address storage in warehouses, laboratories, and production buildings, where drum quantities of materials are stored.

Development of the tool included trials at various facilities storing reactive materials. These trials included

analyzing current storage strategies at these locations

determining suggested strategies based on a hazardous materials compatibility storage matrix

referencing a small quantity exemption table

finalizing appropriate strategies based on suggested strategies and the overall risk (i.e., literature searches, laboratory data, engineering and administrative controls)

conducting literature searches and laboratory tests when Material Safety Data Sheets information was insufficient to determine storage strategies. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007.
Application of electron transfer dissociation mass spectrometry in analyses of non‐enzymatically glycated peptides
Authors: Zhang Qibin , Frolov Andrej , Tang Ning , Hoffmann Ralf , van de Goor Tom , Metz Thomas O. , Smith Richard D.
Published: February 2007

Non‐enzymatic glycation of peptides and proteins by D‐glucose has important implications in the pathogenesis of diabetes mellitus, particularly in the context of development of diabetic complications. The fragmentation behavior of glycated peptides produced from reaction of D‐glucose with lysine residues was investigated by electron transfer dissociation (ETD) and collision‐induced dissociation (CID) tandem mass spectrometry. It was found that high abundance ions corresponding to various degrees of neutral water losses, as well as furylium ion production, dominate the CID spectra, and that the sequence‐informative b and y ions were rarely observed when Amadori‐modified peptides were fragmented. Contrary to what was observed under CID conditions, ions corresponding to neutral losses of water or furylium ion production were not observed in the ETD spectra. Instead, abundant and almost complete series of c‐ and z‐type ions were observed regardless of whether the modification site was located in the middle of the sequence or close to the N‐terminus, greatly facilitating the peptide sequencing. This study strongly suggests that ETD is a better technique for proteomic studies of non‐enzymatically glycated peptides and proteins. Published in 2007 by John Wiley & Sons, Ltd.
Effect of matrix crystal structure on ion abundance of carbohydrates by matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
Authors: Williams Taufika Islam , Saggese Diana A. , Wilcox Robert J. , Martin James D. , Muddiman David C.
Published: February 2007

Sample preparation techniques for carbohydrate analysis using matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) are explored, with particular emphasis on analyte/matrix co‐crystallization procedures. While carbohydrates are known to prefer 2,5‐dihydroxybenzoic acid (2,5‐DHB) as the matrix of choice, these analytes are quite specific about matrix crystal structure, which in turn is dependent on the rate of drying of analyte/matrix spots on the MALDI target. With N‐acetylglucosamine (GlcNAc) and N‐acetylneuraminic acid (sialic acid or NeuAc) as test monosaccharides, significant increases in ion abundances are demonstrated with 2,5‐DHB/NeuAc spots (>10‐fold improvement) and 2,5‐DHB/GlcNAc spots (∼5‐fold improvement) with active drying. The fine structure of crystals generated in active and passive drying was investigated using powder diffraction. Passively dried samples were shown to consist of an ordered polymorph, crystallizing in the space group P21/a, while the actively dried samples produced a disordered phase crystallizing in the space group Pa. These data provide the wherewithal to engineer a matrix best suited for carbohydrate analyses. Copyright © 2007 John Wiley & Sons, Ltd.
Aspects of research on groundwater along the rhǒne, rhine and danube
Authors: Danielopol D. L. , Marmonier P.
Published: February 2007

The history of groundwater ecological research carried out during the last 75 years along the Rhǒne, Rhine and Danube alluvial plain is reviewed. Phreatobiology, a concept introduced by Motas (1958), is denned, and the main phases in the development of this research direction dealing with the study of groundwater organisms living in the unconsolidated sediments are reviewed.

During a preecological phase of phreatobiology, students were interested mainly in the discovery of exciting groundwater organisms and the explanation of their origin. Modern groundwater ecological research began with Schwoerbel's investigations of the Upper Danube alluvial sediments in the beginning of the 1960s. Progress in phreatobiological research was made during the last twenty years through the description of the complex mosaic of habitats in the Rhǒne and Danube plains by French and Austrian students, by applied and theoretical research carried out on the Upper Rhine by S. Husmann.

Three main directions of modern groundwater ecological research are discussed in detail: the ecotone approach developed by students of the University of Lyon on the Rhǒne; the ‘minimalist’ approach, the study of a reduced groundwater ecosystem in the wetland area of the Danube, near Vienna, carried out by an interdisciplinary team; and finally, the ecotoxicological approach developed by Dutch scientists working on the lower Rhine plain. Modern ecological research has inspired groundwater ecology with new concepts and ideas, so that phreatobiology has today expanded into a progressive field of research which complements the other two limnological subject areas, the study of lentic and lotic surface waters.
Effects of regulation on the flow regime of the river Murray, Australia
Authors: Maheshwari B. L. , Walker K. F. , McMahon T. A.
Published: February 2007

The flow regime of the River Murray has changed markedly over the last century, and especially the last 50 years, through increased diversions, construction of dams, weirs and levees and changes in operational procedures. A model developed by the Murray–Darling Basin Commission is used to compare simulated natural (unregulated) flows at eight stations with those at seven consecutive stages in the development of regulation. Monthly and annual average flows and coefficients of variation and skewness were computed, and the flow‐duration, peak‐flow and low‐flow characteristics curves plotted. The results confirm that average monthly and annual flows are now considerably lower than those which prevailed under natural conditions. The seasonal distribution of flows has changed in the upper Murray, owing to the influence of dams. Flow‐duration characteristics now vary considerably along the river, whereas there was little change under natural conditions. The effect of regulation on flow‐duration characteristics is minimal at Albury and becomes more pronounced downstream; it is most apparent in regard to flows exceeded 20–80% of the time. The magnitude of average annual floods (annual exceedance probability 50%) has been reduced by over 50% at all stations, but big floods (average recurrence interval 20 years or more) are little affected. Further, the low flows for a given annual non‐exceedance probability are higher under regulated conditions than those under natural conditions. These changes have profound implications for communities of native plants and animals in both riverine and floodplain environments, and also for the long‐term utility of the river as a resource.
Downstream effect of impoundments on stoneflies: Case study of an epipotamal reach of the Jihlava river, Czech Republic
Authors: Helešic Jan , Sedlaak Edmund
Published: February 2007

Different habitat types were sampled monthly at a sampling site ca. 12 km downstream from the Dalešice dam on the Jihlava River beginning before impoundment (1976–1978), prior to the addition of heated wastewaters to the reservoir (1984–1985) and from 1987 to 1989. Plecoptera was one of the model groups of macrozoobenthos that significantly responded to changed conditions of flow, temperature and chemistry of river water. There was an increase in species richness (from five to 14 species), species diversity (about double), density and biomass (about 18 to 40 times greater). The study area was originally an epipotamal (barbel) zone with a typical Plecoptera species composition—Perla burmersteriana, Isoperla grammatica, Nemoura cinerea, Leuctra digitata and L. fusca. After river impoundments the investigated reach is a typical metarhithral (grayling) zone. Production of the Plecoptera community in the river reaches affected by the dams increased (riffle, from 1.37 to 23.53; pool, from 0.26 to 6.98 gm−2y−1). It was similar to production in a rhithral (trout or grayling) zone with a typical species composition of rheophilic and cold‐water species (e.g. Perlodes microcephala, Isoperla difformis, I. oxylepis, Siphonoperla torrentium, Amphinemura borealis).

The authors thank Professor František Kubiaček from our department, Professor Richard J. Strange, Tennessee University, Knoxville USA, Professor James V. Ward, Colorado State University, Fort Colins USA and an anonymous reviewer for revising the manuscript and numerous helpful suggestions. This final research was supported by grant No. 204/93/2051 from Grant Agency of Czech Republic.
Activity and abundance of bacterioplankton in three diverse lowland water courses
Authors: Yamakanamardi S. M. , Goulder R.
Published: February 2007

The hypothesis that the activity and abundance of bacterioplankton were similar in two low‐level fenland water courses, but were different from those in a high‐level main river, was rejected. Mean values of Vmax for glucose mineralization, Vmax per bacterium, abundance of free‐living and total directly counted bacteria, abundance of colony‐forming units and percentage of culturable bacteria were similar in the low‐level Beverley and Barmston Drain and in the River Hull, but were less in the low‐level Holderness Drain. The less favourable regime in the Holderness Drain was related to intermittently acid conditions. Temporal variation by bacterioplankton in all three water courses was, however, also related to environmental variables other than pH, notably temperature, chlorophyll, biochemical oxygen demand, current velocity, total suspended solids and particulate organic matter. The activity and abundance of bacterioplankton appeared to have increased in the River Hull between 1975–1976 and 1992–1994.
Suitability indices for juvenile 0+ roach [rutilus rutilus (l.)] using point abundance sampling data
Authors: Garner Paul
Published: February 2007

A habitat suitability model is derived for juvenile 0+ roach [Rutilus rutilus (L.)] in the river Great Ouse (UK) using data collected by point abundance sampling by electrofishing. A total of 1718 point samples was used in the analysis. Of these, 392 contained juvenile roach. Polynomial equations describing habitat suitability are derived from depth, mean substratum particle diameter and water velocity data, and an index of plant cover suitability is described. Optimum conditions for roach are a depth of 1 m with a coarse (particle diameter 15–20 mm) substratum and negligible velocity, in the presence of floating and submerged broadleaved plant cover. The model is capable of discerning between null (fish absent) and non‐null (fish present) points in the original data set. It is shown that sampling effort may be reduced by approximately 60% without altering the model's predictions.