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Premise: Shared geographical patterns of population genetic variation among related species is a powerful means to identify the historical events that drive diversification. The Sphagnum capillifolium complex is a group of closely related peat mosses within the Sphagnum subgenus Acutifolia and contains several circumboreal species whose ranges encompass both glaciated and unglaciated regions across the northern hemisphere. In this paper, we (1) inferred the phylogeny of subg. Acutifolia and (2) investigated patterns of population structure and genetic diversity among five circumboreal species within the S. capillifolium complex. Methods: We generated RAD sequencing data from most species of the subg. Acutifolia and samples from across the distribution ranges of circumboreal species within the S. capillifolium complex. Results: We resolved at least 14 phylogenetic clusters within the S. capillifolium complex. Five circumboreal species show some common patterns: One population system comprises plants in eastern North America and Europe, and another comprises plants in the Pacific Northwest or around the Beringian and Arctic regions. Alaska appears to be a hotspot for genetic admixture, genetic diversity, and sometimes endemic subclades. Conclusions: Our results support the hypothesis that populations of five circumboreal species within the S. capillifolium complex survived in multiple refugia during the last glacial maximum. Long‐distance dispersal out of refugia, population bottlenecks, and possible adaptations to conditions unique to each refugium could have contributed to current geographic patterns. These results indicate the important role of historical events in shaping the complex population structure of plants with broad distribution ranges. [ABSTRACT FROM AUTHOR]

Since 2015, the Innovative Technology for Arctic Exploration (ITAE) program has supported maritime technology development that contributes to economic growth, ocean health, and ocean management in Alaska. The program does this in multiple ways: through public-private partnerships, platform and small-scale sensor design, and research to operations, commercialization, and application of science-driven technologies. ITAE is a high-risk, high-reward research collaborative that provides support and expertise for creative scientists pursuing highly innovative research solutions with the potential for broad impact in US Arctic marine sciences. This program is funded through NOAA to support projects that may be overlooked in the traditional peer-review process because of their inherent risk. However, not all risks lead to success, not every risk leads to failure, and not all failures eliminate success. Development and growth are nurtured by risk and temporary setbacks. The science advanced by these researchers and collaborators forges new paths of discovery. While the Arctic is an excellent testbed, in part, due to its extreme conditions, the technologies and lessons detailed here are transferable to oceanographic research outside of the Arctic. This paper reviews the ITAE program as well as the successes and failures of this dedicated Arctic innovation collaborative at the NOAA Pacific Marine Environmental Laboratory. [ABSTRACT FROM AUTHOR]

This paper describes a remotely monitored buoy that, when deployed in open water prior to freeze up, permits scientists to monitor not only temperature with depth, and hence freeze up and sea ice thickness, but also the progression of sea ice development—e.g., the extent of cover at a given depth as it grows (solid fraction), the brine volume of the ice, and the salinity of the water just below, which is driven by brine expulsion. Microstructure and In situ Salinity and Temperature (MIST) buoys use sensor "ladders" that, in our prototypes, extend to 88 cm below the surface. We collected hourly measurements of surface air temperature and water temperature and electrical impedance every 3 cm to track the seasonal progression of sea ice growth in Elson Lagoon (Utqiaġvik, Alaska) over the 2017/18 ice growth season. The MIST buoy has the potential to collect detailed sea ice microstructural information over time and help scientists monitor all parts of the growth/melt cycle, including not only the freezing process but the effects of meteorological changes, changing snow cover, the interaction of meltwater, and drainage. Significance Statement: There is a need to better understand how an increasing influx of freshwater, one part of a changing Arctic climate, will affect the development of sea ice. Current instruments can provide information on the growth rate, extent, and thickness of sea ice, but not direct observations of the structure of the ice during freeze up, something that is tied to salinity and local air and water temperature. A first deployment in Elson Lagoon in Utqiaġvik, Alaska, showed promising results; we observed fluctuations in ice temperatures in response to brief warmings in air temperature that resulted in changes in the conductivity, liquid fraction, and brine volume fraction within the ice. [ABSTRACT FROM AUTHOR]

Food cellars, otherwise referred to as ice or meat cellars, (lednik in Russian, k'aetyran in Chukchi, sigluaq in Iñupiaq, and siqlugaq in Yupik) are a natural form of refrigeration in permafrost or seasonally frozen ground used to preserve, age, and ferment foods harvested for subsistence, including marine mammals, birds, fish, and plants. Indigenous peoples throughout the Arctic have constructed cellars in frozen ground for millennia. This paper focuses on cellars in Russian and American coastal and island communities of the Bering Strait, the region otherwise known as Beringia. This area has a unique, culturally rich, and politically dynamic history. Many traditions associated with cellars are threatened in Chukchi communities in Russia because of the impacts of climate change, relocation, dietary changes, and industrial development. However, even with warmer temperatures, cellars still provide a means to age and ferment food stuffs following traditional methods. In cooperation with local stakeholders, we measured internal temperatures of 18 cellars in 13 communities throughout the Bering Strait region and northern Alaska. Though cellars are widely used in permafrost regions, their structure, usage, and maintenance methods differ and exhibit influences of local climates, traditions, and economic activities. Monitoring internal temperatures and recording structural descriptions of cellars is important in the face of climate change to better understand the variety and resilience of living adaptations in different cold regions. [ABSTRACT FROM AUTHOR]

Intermittent transitions between turbulent and nonturbulent states are ubiquitous in the stable atmospheric surface layer (ASL). Data from two field experiments in Utqiaġvik, Alaska, and from direct numerical simulations are used to probe these state transitions so as to (i) identify statistical metrics for the detection of intermittency, (ii) probe the physical origin of turbulent bursts, and (iii) quantify intermittency effects on overall fluxes and their representation in closure models. The analyses reveal three turbulence regimes, two of which correspond to weakly turbulent periods accompanied by intermittent behavior (regime 1: intermittent; regime 2: transitional), while the third is associated with a fully turbulent flow. Based on time series of the turbulence kinetic energy (TKE), two nondimensional parameters are proposed to diagnostically categorize the ASL state into these regimes; the first characterizes the weakest turbulence state, while the second describes the range of turbulence variability. The origins of intermittent turbulence activity are then investigated based on the TKE budget over the identified bursts. While the quantitative results depend on the height, the analyses indicate that these bursts are predominantly advected by the mean flow, produced locally by mechanical shear, or lofted from lower levels by turbulent ejections. Finally, a new flux model is proposed using the vertical velocity variance in combination with different mixing length scales. The model provides improved representation (correlation coefficients with observations of 0.61 for sensible heat and 0.94 for momentum) compared to Monin–Obukhov similarity (correlation coefficients of 0.0047 for sensible heat and 0.49 for momentum), thus opening new pathways for improved parameterizations in coarse atmospheric models. Significance Statement: Airflow in the lowest layer of the atmosphere is often modulated by a strong gradient of temperature when the surface is much cooler than the air. Such a regime results in weak turbulence and mixing, and is ubiquitous during nighttime and in polar regions. Understanding and modeling atmospheric flow and turbulence under such conditions are further complicated by "turbulence intermittency," which manifests as periods of strong turbulent activity interspersed in a more quiescent airflow. The turbulent periods dominate the air–surface exchanges even when they occur over a small fraction of the time. This paper develops approaches to detect and classify such intermittent regimes, examines how the turbulent bursts are generated and advected, and offers guidance on representing such regimes in geophysical models. The findings have the potential to advance weather forecasting and climate modeling, particularly in the all-important polar regions. [ABSTRACT FROM AUTHOR]

Indigenous Peoples in the Arctic have for millennia relied on freshwaters for drinking water and freshwater species that comprise important subsistence harvests, which promotes a strong connection to the land and unique understanding of organisms and ecosystem processes and changes. Despite the importance of freshwater biodiversity and ecosystem services to Arctic Indigenous communities, there have been limited attempts to summarise available Indigenous Knowledge (IK) regarding Arctic freshwater systems and to understand how conservation can benefit from this knowledge base.This paper presents a systematic review of literature documenting circumpolar Arctic IK with a focus on freshwater biodiversity in Canada, Greenland, Fennoscandia (Norway, Sweden, and Finland), Russia, and the U.S.A. (Alaska). Standardised search terms and methodologies were used to locate relevant documents using Google Scholar and Google Advanced search engines. Thematic coding was used to identify freshwater biodiversity themes within the identified documents.Documented IK of freshwater biodiversity was found from all five geographic regions and included data on both species presence and habitat changes with potential to affect biodiversity. Canada had the highest number of relevant documents (n = 127), followed by the U.S.A. (Alaska; n = 116), Fennoscandia (n = 38), Russia (n = 27), and Greenland (n = 5). The number of relevant documents with IK published per year was highest in most recent years, from 2010 onwards, in all geographic regions.Fish represented the highest number of faunal observations with 59 species observed, approximately half of which were Salmonidae (29 species). Local‐scale assessment of fish diversity found observations of the highest number of species (11–25) in Alaska, and individual observations of 6–10 species were found throughout Alaska, mainland areas of Canada, and the Kola Peninsula in Russia. Documented IK also contributed new information on historical fish diversity and indicated local‐scale loss or gain of species. Such information is of vital importance to provide long‐term records of fish composition and abundance, especially when this information does not exist in other knowledge bases such as western science datasets.Indigenous Knowledge included observations of changes in freshwater and terrestrial habitat associated with a warming climate, such as: decreasing water levels and more draining/drying of lakes and rivers, a shorter period of ice cover (late freeze and early break‐up), decreasing ice thickness, and increasing occurrence of permafrost thaw and eroding banks. Such observations by those who actively rely on Arctic freshwater ecosystem services are important because they signify that change is occurring and that action is needed to mitigate the impacts on freshwater habitats and the biodiversity therein.This study demonstrates that previously documented IK provides valuable information towards determining freshwater biodiversity baselines and patterns of change in the circumpolar Arctic. However, these results do not sufficiently cover the depth and breadth of IK on freshwater biodiversity and ecology held by Indigenous communities. Further work incorporating Indigenous worldviews around freshwater ecology would provide context to the knowledge collected and a deeper understanding of Arctic circumpolar freshwater environments. [ABSTRACT FROM AUTHOR]

Abstract—This paper studies the differences in the trophic resource use in the breeding time between the snow goose Anser caerulescens that is the most abundant in the Arctic and the most widespread brant goose Branta bernicla under the conditions of the main part of the snow goose nesting range (Colville River Delta, Alaska). It was found that the diets of these species consist mainly of grasses and shrubs and to a lesser extent of mosses, sedges, horsetails and forbs, having almost no differences in the composition of resource items. It also was found that both species have the highest foraging costs in coastal habitats and the lowest ones have in marsh habitats. Without significant differentiation of trophic niches, the snow goose has significantly lower foraging costs than the brant goose. A probable transformation mechanism of communities including the species based on their trophic interactions was suggested. [ABSTRACT FROM AUTHOR]

Institutions are influential in mediating the impact of adaptation initiatives at the local level, yet there are disconnects between the goals of multi-scale planning initiatives and community priorities. Research to address this challenge primarily focuses on reform to formal institutions in environmental governance. Meanwhile, knowledge of the specific role informal institutions play in governance processes remains limited. This study increases understanding of the interactions between informal institutions and adaptation using a case study of the Native Village of Wainwright on Alaska's North Slope. Qualitative contextual analysis was employed to identify patterns of informal institution and adaptation associations in historic and contemporary situations in Wainwright. The Adaptation Institutional Analysis Framework developed in this paper extends Elinor Ostrom's Institutional Analysis and Development Framework and is used as a tool to analyse and describe these dynamics. Four primary findings resulted from this analysis (1) identification of informal institutions that have a bearing on adaptation to environmental change and adaptive capacity in Wainwright, (2) insight into how the identified institutions relate to each other and to different aspects of local adaptation, (3) identification of changes in informal institutions that have occurred over time and the potential implications of these changes for local adaptive capacity, and (4) potential opportunities to leverage knowledge of informal institution and adaptation relationships in targeted formal initiatives. The outcomes of this study contribute to an improved understanding of the function and potential of informal institutions in adaptation processes, the benefits of which extend beyond the local context of Wainwright. [ABSTRACT FROM AUTHOR]

Widespread changes in vegetation cover and composition are driving strong impacts on Arctic ecosystem functioning and global climate feedbacks. An accurate characterization of tundra vegetation composition is required to understand how the Arctic will respond to future climate change. However, quantifying tundra vegetation composition over large areas is challenging as commonly-used satellite observations are too coarse, spatially and spectrally, to differentiate low-lying tundra vegetation types. Recent airborne and spaceborne imaging spectroscopy platforms provide better data to characterize vegetation composition. Yet, our ability to characterize vegetation composition with imaging spectroscopy remains largely unexplored in the Arctic, particularly due to a lack of ground observations needed to train and test classification models. To address this problem, we collected very-high-resolution (VHR, ∼5 cm) unoccupied aerial system (UAS) imagery at three low-Arctic tundra sites located on the Seward Peninsula, western Alaska. In this paper, we examine the feasibility of integrating imagery from the UAS and the hyperspectral Airborne Visible/Infrared Imaging Spectrometer, Next Generation (AVIRIS-NG) airborne instrument to map the fractional composition of 12 key Arctic plant functional types (PFTs). To this end, we first mapped the 12 PFTs from our VHR UAS imagery using random forest classification. We then used these UAS-derived PFT maps as ground truth to develop partial least squares regression (PLSR) models to predict the fractional cover (FCover) of each PFT from AVIRIS-NG imagery. We evaluated the performance of our PLSR models using reserved UAS samples, as well as by mapping PFT FCover and dominant PFT for large tundra landscapes. Our results show that 1) Arctic PFTs can be effectively mapped using VHR UAS imagery, with overall accuracy between 86% and 92%, 2) when the UAS mapped PFTs were used to inform PLSR scaling models, the FCover of the 12 PFTs could be effectively estimated from AVIRIS-NG imagery with a mean absolute error (MAE) <0.13, and 3) our PLSR models outperformed traditional, fully constrained least-squares (FCLS) linear mixture analysis and produced high-quality, spatially contiguous PFT FCover and PFT maps that captured vegetation spatial patterns with similar accuracy to those developed from UAS imagery. The developed PLSR models have the potential to be broadly applied for quantifying vegetation composition with AVIRIS-NG images to help monitor tundra vegetation dynamics and improve process-based modeling of tundra ecosystems. • We developed an approach to map the composition of Arctic PFTs with AVIRIS-NG. • We used UAS imagery over an area of ∼600 ha to train our AVIRIS-NG models. • Our models produced robust FCover (RMSE <0.22) and PFT maps (accuracy >84%). • Our multi-scale method outperformed traditional spectral unmixing methods. [ABSTRACT FROM AUTHOR]

This paper presents estimates of the potential health-related economic benefits of providing universal access to in-home water and sanitation services to households in rural Alaska. In particular, we use data on disease incidence rates, health care costs, and local estimates of the impact of piped water on disease reduction to estimate the potential health-related economic benefits of providing universal access to piped water in the Yukon Kuskokwim (Y.K.) Delta region of Alaska. We include estimates of avoided treatment and diagnosis costs as well as private benefits associated with reduced morbidity and mortality associated with improved access to in-home piped water. To our knowledge, these are the first estimates of the economic benefits of improved access to water and sanitation in rural Alaska and the Arctic. Our analysis suggests increased access to in-home piped water in the region may yield substantial reductions in direct medical expenses incurred by public agencies and families, as well as reductions in time and travel costs associated with improved health outcomes. These benefits, along with the array of health and non-health-related benefits not included in our analysis, may provide new impetus to expanding access to high-quality water and sanitation services in the region. [ABSTRACT FROM AUTHOR]

Although the Arctic comprises one-third of the global coastline and has some of the fastest eroding coasts, current tools for quantifying permafrost erosion are unable to explain the episodic, storm-driven erosion events that occur in this region. In this paper, we present a novel multi-physics finite element model for the numerical simulation of Arctic coastal permafrost degradation: the terrestrial component of the Arctic Coastal Erosion (ACE) model. This model is comprised of two main ingredients: (1) a solid mechanics model that calculates the three-dimensional (3D) stress, strain and displacement fields of the underlying permafrost developing in response to a frozen water content dependent plasticity model, and (2) a novel thermal model governing the 3D heat conduction and solid–liquid phase change occurring within the permafrost. These two physics sets are coupled via a sequential thermo-mechanical coupling scheme developed within the Albany LCM open-source finite element code. Unlike prior approaches, our modeling methodology enables failure from any allowable deformation (block failure, thermo-denudation, thermo-abrasion); moreover, failure modes develop from constitutive (rather than empirical) relationships inherent in the underlying finite element model. Elements are dynamically removed from the underlying finite element mesh so as to simulate transient permafrost erosion events. Our thermo-mechanical terrestrial model is evaluated on a pseudo-realistic problem in which a slice of permafrost is exposed to realistic oceanic and atmospheric forcing boundary condition data occurring at Drew Point, Alaska in July 2018. [ABSTRACT FROM AUTHOR]