cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.22354732
title: Inventory and kinematics of active and transitional rock glaciers in the Southern Alps of New Zealand from Sentinel-1 InSAR

description: In this study, we inventoried and mapped the active and transitional rock glaciers in the central part of the Southern Alps, New Zealand, using Sentinel-1 InSAR (interferometric synthetic aperture radar) data. We used forty-three interferograms acquired between 2015 and 2019 with time intervals between six days and two years along with orthoimage analyses. A total of 123 rock glaciers were identified, of which 40 are active; that is, displaying velocities higher than 10 cm/yr. The remaining landforms are considered transitional. Among the complete sample of rock glaciers inventoried, 9 may also be interpreted as debris-covered glacierets. The number of inventoried landforms is low compared to what is observed in other similar mountain ranges, such as the European Alps. We explain this by the reduced vertical extent of the periglacial belt and the generally steep topography often not favorable for rock glacier development. Additionally, the motion rates appear relatively low. We hypothesize that a mean annual air temperature at the rock glacier locations well above 0°C is the main reason for this. These conditions may have resulted in significant ground ice melt. Rock glaciers in the Southern Alps are thus in an inactivation phase, which is expressed by typical morphologies such as stable fronts.
DOI: 10.6084/m9.figshare.22354732.v2
title: Inventory and kinematics of active and transitional rock glaciers in the Southern Alps of New Zealand from Sentinel-1 InSAR

description: In this study, we inventoried and mapped the active and transitional rock glaciers in the central part of the Southern Alps, New Zealand, using Sentinel-1 InSAR (interferometric synthetic aperture radar) data. We used forty-three interferograms acquired between 2015 and 2019 with time intervals between six days and two years along with orthoimage analyses. A total of 123 rock glaciers were identified, of which 40 are active; that is, displaying velocities higher than 10 cm/yr. The remaining landforms are considered transitional. Among the complete sample of rock glaciers inventoried, 9 may also be interpreted as debris-covered glacierets. The number of inventoried landforms is low compared to what is observed in other similar mountain ranges, such as the European Alps. We explain this by the reduced vertical extent of the periglacial belt and the generally steep topography often not favorable for rock glacier development. Additionally, the motion rates appear relatively low. We hypothesize that a mean annual air temperature at the rock glacier locations well above 0°C is the main reason for this. These conditions may have resulted in significant ground ice melt. Rock glaciers in the Southern Alps are thus in an inactivation phase, which is expressed by typical morphologies such as stable fronts.
DOI: 10.6084/m9.figshare.23699255.v1
title: Yukon ice patches: Bryophyte generation from ancient ice-entombed assemblages

description: In Southwestern Yukon, ice patches have shown substantial retreat since the Little Ice Age (1600–1900 AD) in response to warming trends. These ice patches support unique alpine wetlands that have formed habitats for diverse flora and fauna over millennia. With ice retreat, pristine bryophyte populations are exposed beneath accumulated ancient dung. Given that bryophytes have been shown to survive extreme conditions including ice entombment and can regenerate from viable cells, emergent ice margin bryophyte and dung samples from the Granger and Gladstone ice patches were assayed for regrowth potential under growth chamber conditions. Diaspore (spore/fragment) generation of species found in the original subfossil material was indicated in 68 percent of assays, emphasizing the cyclical establishment of ancient ice patch vegetation. One of the oldest samples, dating 4036 calibrated years BP from the Gladstone ice patch margin, showed remarkable bryophyte generation from diaspores in dung. These Yukon ice patches form reservoirs of cryopreserved biota and have a critical role in maintaining alpine diversity, which provides summer refuge for caribou and other alpine fauna. Ice margin fluctuations, which bury and release populations through time, are part of a complex revegetation sequence in alpine regions that has followed deglaciation.
DOI: 10.6084/m9.figshare.24794179
title: Methane emissions from subglacial meltwater of three alpine glaciers in Yukon, Canada

description: Subglacial meltwater of land-terminating glaciers in Greenland and Iceland are sources of methane (CH<sub>4</sub>) to the atmosphere, but sparse empirical data exist about the spatial distribution of subglacial CH<sub>4</sub> production and emission from glaciers in other regions of the world. This study presents the first measurements of CH<sub>4</sub> emissions from the subglacial meltwater of three outlet glaciers of the St. Elias Mountains in Yukon, Canada. Dissolved CH<sub>4</sub> concentrations were highly elevated at 45, 135, and 250 times compared to the atmospheric equilibrium concentration in the meltwater of Dusty, Kluane, and Donjek glaciers, respectively. Dissolved CO<sub>2</sub> concentrations were depleted relative to the atmospheric equilibrium. This points to the meltwater being a source of CH<sub>4</sub> and a sink of CO<sub>2</sub>. Stable carbon (<sup>13</sup>C) and hydrogen (<sup>2</sup>H) isotopic signatures of the subglacial CH<sub>4</sub> were depleted compared to atmospheric CH<sub>4</sub> at all sites, indicating both biotic and abiotic sources and possible alteration from bacterial CH<sub>4</sub> oxidation in the meltwater. No relation was found between CH<sub>4</sub> concentrations in the meltwater and the meltwater chemistry or the size of the glaciers in this study. These findings suggest that CH<sub>4</sub> emissions from subglacial environments under alpine glaciers may be a more common phenomenon than previously thought.
DOI: 10.6084/m9.figshare.22277032
title: Plant succession on glacial moraines in the Arctic Brooks Range along a &gt;125,000-year glacial chronosequence/toposequence

description: Widespread glacial retreat is now occurring in many arctic mountain ranges, yet little is known about primary succession following deglaciation in these settings. Newly created habitats could provide refugia for flora and fauna whose ranges are threatened elsewhere by rapid warming. To assess vegetation responses to glacial retreat in an arctic–alpine setting, we first describe plant community development on two recently deglaciated moraines in the Brooks Range. We then compare these recent communities with communities developed along a moraine chronosequence that spans &gt;125,000 years and ranges in altitude between 800 and 1,700 m.a.s.l. Results show that (1) within twenty-two to thirty-six years following deglaciation, primary succession begins with the assembly of small communities of eight to thirteen vascular and nonvascular plant species; (2) species turnover is low, with many pioneer taxa, particularly lichens, persisting at the oldest sites and across all altitudes; and (3) overall, succession is directional and slow, with species richness increasing for up to 25,000 years, and percentage vegetation cover reaching &gt;100 percent on the oldest glacial deposits. This is the first vegetation study on primary succession in the high central Brooks Range, and it supplies a previously missing alpine element within a vegetation transect across northern Alaska’s bioclimatic gradient.
DOI: 10.6084/m9.figshare.22277032.v1
title: Plant succession on glacial moraines in the Arctic Brooks Range along a &gt;125,000-year glacial chronosequence/toposequence

description: Widespread glacial retreat is now occurring in many arctic mountain ranges, yet little is known about primary succession following deglaciation in these settings. Newly created habitats could provide refugia for flora and fauna whose ranges are threatened elsewhere by rapid warming. To assess vegetation responses to glacial retreat in an arctic–alpine setting, we first describe plant community development on two recently deglaciated moraines in the Brooks Range. We then compare these recent communities with communities developed along a moraine chronosequence that spans &gt;125,000 years and ranges in altitude between 800 and 1,700 m.a.s.l. Results show that (1) within twenty-two to thirty-six years following deglaciation, primary succession begins with the assembly of small communities of eight to thirteen vascular and nonvascular plant species; (2) species turnover is low, with many pioneer taxa, particularly lichens, persisting at the oldest sites and across all altitudes; and (3) overall, succession is directional and slow, with species richness increasing for up to 25,000 years, and percentage vegetation cover reaching &gt;100 percent on the oldest glacial deposits. This is the first vegetation study on primary succession in the high central Brooks Range, and it supplies a previously missing alpine element within a vegetation transect across northern Alaska’s bioclimatic gradient.
DOI: 10.6084/m9.figshare.22354732.v1
title: Inventory and kinematics of active and transitional rock glaciers in the Southern Alps of New Zealand from Sentinel-1 InSAR

description: In this study, we inventoried and mapped the active and transitional rock glaciers in the central part of the Southern Alps, New Zealand, using Sentinel-1 InSAR (interferometric synthetic aperture radar) data. We used forty-three interferograms acquired between 2015 and 2019 with time intervals between six days and two years along with orthoimage analyses. A total of 123 rock glaciers were identified, of which 40 are active; that is, displaying velocities higher than 10 cm/yr. The remaining landforms are considered transitional. Among the complete sample of rock glaciers inventoried, 9 may also be interpreted as debris-covered glacierets. The number of inventoried landforms is low compared to what is observed in other similar mountain ranges, such as the European Alps. We explain this by the reduced vertical extent of the periglacial belt and the generally steep topography often not favorable for rock glacier development. Additionally, the motion rates appear relatively low. We hypothesize that a mean annual air temperature at the rock glacier locations well above 0°C is the main reason for this. These conditions may have resulted in significant ground ice melt. Rock glaciers in the Southern Alps are thus in an inactivation phase, which is expressed by typical morphologies such as stable fronts.
DOI: 10.6084/m9.figshare.22110598
title: Genetic analysis of the frozen microbiome at 7900 m a.s.l., on the South Col of Sagarmatha (Mount Everest)

description: Microbial communities in alpine environments &gt;7,500 m.a.s.l. have not been well studied using modern cultivation-independent sequencing approaches due to the challenges and danger associated with reaching such high elevations. For this reason, we know little about the microorganisms found in sediments on Earth’s tallest mountains, how they reach these surfaces, and how they survive and remain active at such extreme elevations. Here, we explore the microbial diversity recovered from three sediment samples collected from the South Col (~7,900 m.a.s.l.) of Sagarmatha (Mount Everest) using both culturing and next generation sequencing approaches (16S rRNA gene, internal transcribed spacer [ITS] region, and 18S rRNA gene sequencing). Both approaches detected very low diversity of bacteria, protists, and fungi that included a combination of cosmopolitan taxa and specialized microorganisms often found at high elevations like those of the genera <i>Modestobacter</i> and <i>Naganishia</i>. Though we managed to grow viable cultures of many of these taxa, it remains likely that few, if any, can be active in situ at the South Col. Instead, these high-elevation surfaces may act as deep-freeze collection zones of organisms deposited from the atmosphere or left by climbers scaling the Earth’s highest mountain.
DOI: 10.6084/m9.figshare.22110598.v1
title: Genetic analysis of the frozen microbiome at 7900 m a.s.l., on the South Col of Sagarmatha (Mount Everest)

description: Microbial communities in alpine environments &gt;7,500 m.a.s.l. have not been well studied using modern cultivation-independent sequencing approaches due to the challenges and danger associated with reaching such high elevations. For this reason, we know little about the microorganisms found in sediments on Earth’s tallest mountains, how they reach these surfaces, and how they survive and remain active at such extreme elevations. Here, we explore the microbial diversity recovered from three sediment samples collected from the South Col (~7,900 m.a.s.l.) of Sagarmatha (Mount Everest) using both culturing and next generation sequencing approaches (16S rRNA gene, internal transcribed spacer [ITS] region, and 18S rRNA gene sequencing). Both approaches detected very low diversity of bacteria, protists, and fungi that included a combination of cosmopolitan taxa and specialized microorganisms often found at high elevations like those of the genera <i>Modestobacter</i> and <i>Naganishia</i>. Though we managed to grow viable cultures of many of these taxa, it remains likely that few, if any, can be active in situ at the South Col. Instead, these high-elevation surfaces may act as deep-freeze collection zones of organisms deposited from the atmosphere or left by climbers scaling the Earth’s highest mountain.
DOI: 10.6084/m9.figshare.24374541
title: Hydrological heterogeneity and the plant colonization of recently deglaciated terrain

description: Climate change accelerates glacier retreat, leading to extensive exposure of sediment to light and ecological succession. Succession has traditionally been studied as a chronosequence, where vegetation development is directly correlated with time since glacier retreat or distance from the retreating glacier margin. More recent work has challenged this model, arguing that succession seems to be mainly influenced by heterogeneous conditions at the local scale. The aim of this study was to identify the factors influencing the local-scale establishment of plant communities following glacier recession. Vascular plants and their cover were inventoried in 100 plots (1 m<sup>2</sup>) for a thirty-year-old alluvial plain in front of the Otemma glacier (Swiss Alps). Depth to water table, distance to the glacial main river and to the nearest channel, sediment size, moss, lichen, and biological soil crust cover were measured. Results showed that proglacial margins develop hydrological heterogeneity over a small scale, reflected in the four observed plant communities. These range from the dry <i>Sempervivum</i>-dominated community, on gravel-rich sediments with a deep water table, to the <i>Trifolium</i>-dominated community, close to secondary channels, with the highest plant cover and species richness and incorporating grassland species. Heterogeneity in water availability exerted a critical control on vegetation development.
DOI: 10.6084/m9.figshare.24878376
title: Microbial ecology and activity of snow algae within a Pacific Northwest snowpack

description: Snow algae blooms are common occurrences in alpine systems and contribute to increasing snow and glacial ice melt rates. Despite the cosmopolitan distribution of snow algae, little is known about the role their life cycle plays in community composition and activity in snowpack. Mount Baker, in Washington, USA, is a rapidly changing alpine ecosystem. Here we present estimates of cellular biomass, microbial community composition, and primary productivity measurements associated with surficial snow algae blooms and a vertical profile within a snow pit to characterize the microbial ecology of this snowpack system. <i>Chloromonas</i> was the most abundant algae detected in our samples. Sphingobacteriaceae were the most dominant bacteria in samples where fungi were the most abundant eukaryote, whereas Chitinophagaceae dominated when Chlorophyceae were the most abundant eukaryote. In a snow pit vertical profile, we observed more algae in the green-pigmented, flagellated life cycle stage at depth (~30 cm below the surface) than at the surface where the astaxanthin-rich, aplanospore life cycle stage dominated. Higher resolution analyses revealed that <i>Chloromonas</i>-associated photosynthesis transcripts were more abundant at depth than at the surface of the snowpack. These results suggest that there is a photosynthetic niche within alpine snowpack that has unknown effects on the carbon budget and provides potentially undetected primary productivity resulting in a “cryptic” photosynthetic system.
DOI: 10.6084/m9.figshare.24878376.v1
title: Microbial ecology and activity of snow algae within a Pacific Northwest snowpack

description: Snow algae blooms are common occurrences in alpine systems and contribute to increasing snow and glacial ice melt rates. Despite the cosmopolitan distribution of snow algae, little is known about the role their life cycle plays in community composition and activity in snowpack. Mount Baker, in Washington, USA, is a rapidly changing alpine ecosystem. Here we present estimates of cellular biomass, microbial community composition, and primary productivity measurements associated with surficial snow algae blooms and a vertical profile within a snow pit to characterize the microbial ecology of this snowpack system. <i>Chloromonas</i> was the most abundant algae detected in our samples. Sphingobacteriaceae were the most dominant bacteria in samples where fungi were the most abundant eukaryote, whereas Chitinophagaceae dominated when Chlorophyceae were the most abundant eukaryote. In a snow pit vertical profile, we observed more algae in the green-pigmented, flagellated life cycle stage at depth (~30 cm below the surface) than at the surface where the astaxanthin-rich, aplanospore life cycle stage dominated. Higher resolution analyses revealed that <i>Chloromonas</i>-associated photosynthesis transcripts were more abundant at depth than at the surface of the snowpack. These results suggest that there is a photosynthetic niche within alpine snowpack that has unknown effects on the carbon budget and provides potentially undetected primary productivity resulting in a “cryptic” photosynthetic system.
DOI: 10.6084/m9.figshare.24374541.v1
title: Hydrological heterogeneity and the plant colonization of recently deglaciated terrain

description: Climate change accelerates glacier retreat, leading to extensive exposure of sediment to light and ecological succession. Succession has traditionally been studied as a chronosequence, where vegetation development is directly correlated with time since glacier retreat or distance from the retreating glacier margin. More recent work has challenged this model, arguing that succession seems to be mainly influenced by heterogeneous conditions at the local scale. The aim of this study was to identify the factors influencing the local-scale establishment of plant communities following glacier recession. Vascular plants and their cover were inventoried in 100 plots (1 m<sup>2</sup>) for a thirty-year-old alluvial plain in front of the Otemma glacier (Swiss Alps). Depth to water table, distance to the glacial main river and to the nearest channel, sediment size, moss, lichen, and biological soil crust cover were measured. Results showed that proglacial margins develop hydrological heterogeneity over a small scale, reflected in the four observed plant communities. These range from the dry <i>Sempervivum</i>-dominated community, on gravel-rich sediments with a deep water table, to the <i>Trifolium</i>-dominated community, close to secondary channels, with the highest plant cover and species richness and incorporating grassland species. Heterogeneity in water availability exerted a critical control on vegetation development.
DOI: 10.6084/m9.figshare.22802627
title: Will current protected areas harbor refugia for threatened Arctic vegetation types until 2050? A first assessment

description: Arctic vegetation is crucial for fauna and the livelihoods of Northern peoples and is tightly linked to climate, permafrost soils, and water. Yet, a comprehensive understanding of climate change effects on Arctic vegetation is lacking. Protected areas cannot halt climate change but could reduce future pressure from additional drivers, like land use change and local industrial pollution. Therefore, it is crucial to understand the contribution of protected areas in safeguarding threatened Arctic vegetation types. We compare the present baseline with 2050 predictions of circumpolar Arctic vegetation type distributions and demonstrate an overrepresentation of dominant vegetation types and an underrepresentation of declining vegetation types within protected areas. Our study predicts five of eight assessed tundra vegetation types to be threatened by 2050, following International Union for Conservation of Nature criteria. Further, we mapped potential climate change refugia, areas with the highest potential for safeguarding threatened vegetation types. This study provides an essential first step assessing vegetation type vulnerability based on predictions covering 42 percent of Arctic landscapes. The co-development of new protective measures by policymakers and Indigenous peoples at a pan-Arctic scale requires more robust and spatially complete vegetation predictions, as increasing pressures from resource exploration and infrastructure development threaten the sustainable development of the rapidly thawing and greening Arctic.
DOI: 10.6084/m9.figshare.22802627.v2
title: Will current protected areas harbor refugia for threatened Arctic vegetation types until 2050? A first assessment

description: Arctic vegetation is crucial for fauna and the livelihoods of Northern peoples and is tightly linked to climate, permafrost soils, and water. Yet, a comprehensive understanding of climate change effects on Arctic vegetation is lacking. Protected areas cannot halt climate change but could reduce future pressure from additional drivers, like land use change and local industrial pollution. Therefore, it is crucial to understand the contribution of protected areas in safeguarding threatened Arctic vegetation types. We compare the present baseline with 2050 predictions of circumpolar Arctic vegetation type distributions and demonstrate an overrepresentation of dominant vegetation types and an underrepresentation of declining vegetation types within protected areas. Our study predicts five of eight assessed tundra vegetation types to be threatened by 2050, following International Union for Conservation of Nature criteria. Further, we mapped potential climate change refugia, areas with the highest potential for safeguarding threatened vegetation types. This study provides an essential first step assessing vegetation type vulnerability based on predictions covering 42 percent of Arctic landscapes. The co-development of new protective measures by policymakers and Indigenous peoples at a pan-Arctic scale requires more robust and spatially complete vegetation predictions, as increasing pressures from resource exploration and infrastructure development threaten the sustainable development of the rapidly thawing and greening Arctic.