This paper presents the first rock mass loss data for uncut clasts from continental Antarctica. A rock mass loss experiment using doleritic rock samples was conducted over a seven-year period, between 2008 and 2014, at the Vesleskarvet nunataks, Western Dronning Maud Land. The data show that approximately 10% of clasts suffered a mass loss that is an order of magnitude greater than the remaining 90% of clasts. Thus, the observed rock mass loss is suggested to occur in a series of events that are impossible to predict in terms of frequency and/or magnitude. However, extrapolating from the data obtained during the seven-year period indicates that rates of mass loss are slow and of the order of 1% per 100 years. Direct erosion by wind (including abrasion) as well as mechanical and chemical weathering are suggested to be responsible for rock mass loss. Rock properties, the weathering environment, and a lack of available moisture may be contributing factors to the slow rate of rock decay. This paper suggests that in this area of Antarctica, the slow rate of rock mass loss increases the longevity of existing periglacial landforms such as patterned ground and blockfields, but inhibits development of new patterned ground through the slow production of fines.

Buddhist sacred walls, called mani walls, are common between Langtang Village and Kyanjin Gompa in Langtang Valley, Nepal Himalaya. The objective of this study was to interview local informants about the mani wall traditions and to use lichenometry to resolve discrepancies regarding the maintenance of the mani walls. The maximum diameters of the lichen Rhizocarpon geographicum were measured on each of 24 mani walls. An apparent lichen growth curve was developed using five sources of indirect data, including the foundation of one stupa (sacred monument) and two locations of former ice cover, for which ages were obtained from local informants, and two debris ridges that had been dated by ¹⁰Be. The direct method was pursued by measuring the maximum diameters of 20 lichens in remote locations in both 2009 and 2014. Based on the indirect method, the mani walls are cleaned on a geometric mean cycle time of 13 years. The direct and indirect methods yield equivalent ages when the minimum direct growth rate (geometric mean divided by geometric standard deviation) is used for older ages (>400 years), while the maximum direct growth rate (geometric mean multiplied by geometric standard deviation) is used for younger ages (<50 years).

We provide the first detailed documentation of a lava tube cave with permanent ice on the Hawaiian Islands. “Mauna Loa Icecave” had been surveyed in 1978; we periodically visited the cave and monitored temperature, humidity, and ice levels from 2011 to 2014. Perennial ice still blocks the lava tube at the terminal end, but a previously present large ice floor (estimated 260 m²) has disappeared. A secondary mineral deposited on the cave walls is interpreted as the result of past sustained ice levels. Airflow measurements, scallop patterns in the ice, strong temperature and humidity variations, and ice volume fluctuations indicate ventilation of the cave, which suggests that additional ice loss could occur rapidly. The scientific potential of the ice record remains to be explored, before it is lost.

In the four years after the 2008 eruption and burial of Kasatochi Island volcano, erosion and the return of bird activity have resulted in new and altered land surfaces and initiation of ecosystem recovery. We examined fertility characteristics of the recently deposited pyroclastic surfaces, patches of legacy pre-eruptive surface soil (LS), and a post-eruptive surface with recent bird roosting activity. Pyroclastic materials were found lacking in N, but P, K, and other macronutrients were in sufficient supply for plants. Erosion and leaching are moving mobile P and Fe downslope to deposition fan areas. Legacy soil patches that currently support plants have available-N at levels (10–22 mg N kg^-1) similar to those added by birds in a recent bird roosting area. Roosting increased surface available N from <1 mg N kg^-1 in the new pyroclastic surfaces to up to 42 mg N kg^-1 and increased soil biological respiration of CO₂ from essentially zero to a level about 40% that of the LS surface. Laboratory plant growth trials using Lupinus nootkatensis and Leymus mollis indicated that the influence of eroded and redeposited LS in amounts as little as 10% by volume mixed with new pyroclastic materials could aid plant recovery by supplying vital N and soil biota to plants as propagules are introduced to the new surface. Erosion-exposure of fertile pre-eruptive soils and erosion-mixing of pre-eruptive soils with newly erupted materials, along with inputs of nutrients from bird activities, each will exert significant influences on the surface fertility and recovery pattern of the new post-eruptive Kasatochi volcano. For this environment, these influences could help to speed recovery of a more diverse plant community by providing N (LS and bird inputs) as alternatives to relying most heavily on N-fixing plants to build soil fertility.

In the aseasonal tropical alpine environment, plants experience frequent oscillations of air temperature around zero, but little is known about the leaf temperatures of different plant growth forms in dry versus humid climatic conditions. During July–August 2007, we measured air temperature at 100 cm and 20 cm above the ground, soil temperature at 1 cm and 10 cm depth, and temperatures of leaves and stems of tropical alpine plants on the eastern (windward and cloudy) and western (leeward and sunny) sides of the Antisana volcano (Ecuador) between 4100 m and 4600 m, with the aim of examining the effects of climate and growth forms on leaf temperature. The sunnier climate on the western side of the mountain provided a much broader thermal envelope, in which only leaves of low-statured plants showed significant departure from air temperature during the day. In contrast, most plants had warmer leaves than was the air temperature on the eastern side, and except for cushion plants, the difference in temperature was progressively greater in leaves of taller plants. Plants warmed up significantly faster on the western side and at higher elevations, with the fastest warming rates of 13–15 K h^-1 observed in erect herbs. Night cooling rates did not differ between the opposite mountain sides or between elevations. Erect herbs cooled at the fastest rates (3 K h^-1), whereas cushion plants cooled at the slowest rates (about 1 K h^-1). Height aboveground along with aspect (west vs. east) were the most significant determinants of the leaf thermal microclimate during the day, with elevation having no effect. Low-statured plants experienced more extreme and more variable microclimates than taller plants in sunnier and drier conditions, but the effect of plant height was almost negligible in humid and cloudy climates. In all climatic conditions, cushion plants performed better than any other growth form by achieving higher temperature during the day and preventing rapid cooling during the night.

Little information is currently available about heavy metal dynamics during litter decomposition in areas receiving few inputs of exotic metals. A field litter decomposition experiment was conducted during the winter in an alpine forest river on the eastern Tibetan Plateau. Concentrations, release rates, and release rate per day of chromium (Cr), cadmium (Cd), and lead (Pb) were investigated in the foliar litter of willow (Salix paraplesia), azalea (Rhododendron lapponicum), cypress (Sabina saltuaria), and larch (Larix mastersiana) during the prefreezing, freezing, and thawing periods. Concentrations of Cr in willow, cypress, and larch; Cd in all foliar litter types; and Pb in azalea foliar litter increased following incubation over an entire winter. Both Cr and Pb showed patterns of accumulation during the prefreezing period and patterns of release in the freezing and thawing periods, but Cd showed accumulation in all three periods. Water temperature, pH, flow velocity, conductivity, and nutrient availability in the river were significantly related to the dynamics of these heavy metals in the decomposing foliar litter. The heavy metal accumulation pattern in running water suggested an absolute increase in metal mass, indicating that litter may act as an efficient metal “cleaner” and contribute to an ecosystem's capacity for self-purification.

In proglacial landscapes, such as western Greenland, eolian transport plays an important role for the influx of particulate material to lakes. On the basis of an analysis of a sediment profile and surface sediments from several lakes, we show that eolian activity has a strong influence on sediment deposition in time and space. Principal component analysis revealed that sediments that accumulated during periods with high eolian activity were enriched in zirconium—originating from coarse silt and sand fractions preferentially transported by wind—and depleted in rubidium. In addition, zirconium to rubidium ratios in the surface sediment of four additional lakes decreased with distance from the ice sheet. Finally, previously published data show that pH and alkalinity tend to be higher in lakes close to the front of the ice sheet, which we speculate is coupled to a larger supply of fresh eolian material. These findings demonstrate that lakes in proglacial landscapes may receive a substantial part of their sediment load through eolian deposition, and that this is especially true close to the glacial outwash plains along the ice margin.

Biological N₂ fixation in high-latitude ecosystems usually exhibits low rates but can significantly contribute to the local N budget. We studied N₂ fixation in three habitats of East European subarctic tundra differing in soil N stocks and fluxes: N-limited vegetated peat plateau (PP), frost formations of bare peat called “peat circles” (PC) with high availability of soil N, and vegetated upland tundra (UT) with low to intermediate N-availability. Nitrogen fixation was measured at field conditions twice during summer 2011 by acetylene reduction assay, and N₂ fixation rates were verified by ¹⁵N₂ fixation assay. Response to variation in nutrients, carbon, and temperature was studied in complementary laboratory experiments. Further, we aimed to link N₂ fixation rates to N deposition and major N transformation rates (gross and net mineralization, plant N uptake) including high N₂O emissions recently found from PC. We hypothesized that N₂O emissions in PC were fueled partly by biologically fixed N. Contrary to that hypothesis, N₂ fixation was found solely in PP (0.01–0.76 mg N m^-2 d^-1), where N₂ was fixed by moss-associated cyanobacteria and heterotrophic soil bacteria. The low N and high P availability corresponded with the occurrence of N₂ fixation in these soils. Nitrogen fixation represented only a small portion of plant N uptake in PP. Conversely, bare PC (as well as vegetated UT) lacked N₂ fixation and thus N₂O efflux is most likely fueled by release of mineral N to the soil through internal nutrient cycling.

We studied in situ litter decomposition at a subalpine (1737 m a.s.l.) and a submontane (570 m) long-term monitoring forest site in the Italian Alps in the period 2000–2003 and 10 years later (2010–2013). Litter bags filled with site-specific (pine needles) and standard (cellulose) litter were exposed in autumn 2000 and 2010 on the soil surface. Cellulose was additionally exposed in litter bags buried at 2 cm soil depth to monitor the effect of soil microclimate. Decomposition rates were calculated after 1, 2, and 3 years of exposition from litter mass loss. Mass loss of litter exposed on soil surface was significantly affected by the site (altitude) and the litter type, while the decade of exposition (2000–2003, 2010–2013) had no significant impact. Litter decomposition was significantly lower at the site at the higher altitude, which was related to the colder climate, and pine needles were decomposed to a significantly lower extent than surface-exposed cellulose. Decomposition of cellulose buried in soil was neither influenced by the decade nor by the site. Cellulose mass loss was higher in soil than on soil surface, which is attributed to the favorable soil microclimate conditions in soil. The better adaptation of the soil population at the submontane site compared to that at the site at the higher altitude for accelerated degradation of easily decomposable compounds (cellulose) was confirmed by a laboratory study.

Across a small geographic area (<180 km), the region of South-West Greenland covers a natural climate gradient. Variation in temperature and precipitation result in marked differences in limnology at three discrete locations: ice sheet margin, inland, and the coast. Replicate lakes from each location were sampled for physical (temperature, light), chemical (dissolved oxygen, pH, conductivity, nutrients), and biological (chlorophyll a [Chl a], photosynthetic pigments) variables on three occasions within a 12-month period: July–August 2010, April–May 2011, and June–July 2011 spanning ice cover. Variation in ice phenology was linked to the climate gradient; however, phytoplankton production and community composition did not differ regionally. Large-scale seasonal fluctuations in temperature and nutrient availability were the strongest predictors of phytoplankton production, with a shift from nitrate to phosphorus controlled production between ice-cover and ice-free conditions. Underlying seasonal drivers, variables predicting production were unique to each location—ice sheet margin (soluble reactive phosphorus), inland (temperature), and coast (silicate)—and reflect local differences in nutrient availability. Results from the current study have important consequences when controls over phytoplankton production in Arctic lakes are inferred from a limited number of sites, but up-scaled to represent pan-Arctic trends.

Freezing/thawing index is an important indicator of climate change, and can be used to estimate depths of the active layer and seasonally frozen ground (SFG). Using the mean monthly grid air temperature from 2000 to 2009 as well as daily air and ground surface temperatures from 12 meteorological stations across the Heihe River Basin, this study investigated spatial and temporal variability of the freezing/thawing index and seasonal soil freeze depth. The mean annual air temperature increased at a rate of 0.35 °C decade^-1 from 1960 to 2013, or approximately 1.9 °C for the 54-year period. We found that the freezing index (FI) showed a decreasing trend over the study area, while the thawing index (TI) had an increasing trend. Changes in both FI and TI are consistent with an increasing mean annual air temperature. The TI and freezing n-factor (n_f) decrease with elevation increase, while FI and thawing n-factor (n_t) increase with elevation. Soil potential seasonal freezing depth was primarily between 1.5 and 2.5 m in permafrost regions. However, the soil maximum freezing depth is below 2.5 m in SFG region.

Avalanche runout distance and return period estimates are essential to snow avalanche risk assessment for hazard mapping and mitigation design. We present a validation of the Space-Time (ST) model, a statistical model that expresses runout distance as a function of return period. The validation is based on field observations of tree damage and tree ring data of infrequent (1:5 to 1:100 year return period) avalanches from 34 paths in the Canadian Rocky and Columbia Mountains. While the ST model has been applied successfully for a longer return period (>100 year) runouts in one path, our validation showed that it does not independently estimate infrequent runout distances with sufficient accuracy for hazard mapping and mitigation design. As with estimating extreme runouts, it should be used in combination with other methods. The model was found to perform differently across mountain ranges, and tended to estimate runout distance downslope of those observed in the field.

The North American glacier ice worm, Mesenchytraeus solifugus (Emery, 1898), is restricted to coastal glaciers in the American Pacific Northwest with a puzzling 400 km distribution gap along the Alaska-British Columbia border and several disjunct populations of northern clades in southern latitudes. We illustrate the role of minimum temperatures in ice worm behavior, abundance, and distribution. The study included 200 glaciers and 25 mitochondrial CO1 haplotypes from the species' 5 × 10⁵ km² geographic range. Minimum winter temperatures on the previous summer surface appear to determine: (1) the elevations ice worms occupy, (2) the glaciers that can support them, and (3) the mountain ranges they inhabit. Ice worms do not inhabit glaciers with over-winter temperatures below -7 °C on the previous summer surface. An annelid molecular clock in a Bayesian phylogeny suggests ice worms diverged from an aquatic ancestor 2.23 Ma, emerging as three clades 1.6–1.7 Ma. Cold sensitivity, together with southeast Alaska's geography and past climate, likely created the distribution gap, a hypothesis supported by their phylogeography.