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Attempts to geochemically distinguish between metamorphic-hydrothermal systems that form orogenic gold deposits and both reduced and oxidized magmatic-hydrothermal systems using isotopes or metal associations have proven ambiguous, particularly for orogenic gold and reduced intrusion-related gold systems. The absence of conclusive geochemical discriminators and the overlap in...

Baseline information about declining North American shorebird populations is essential to determine the effects of global warming at low-lying coastal areas of the Arctic and subarctic, where numerous taxa breed, and to assess population recovery throughout their range. We estimated population sizes on the Yukon-Kuskokwim Delta in western Alaska...

The development and application of approaches to detect and quantify environmental DNA (eDNA) have potential to improve our understanding of the distribution, abundance, and health of Atlantic Salmon Salmo salar and Pacific salmon Oncorhynchus spp. Here, we review 61 articles focusing on eDNA applications pertaining to salmon occupying natural...

The McKay’s Bunting (Plectrophenax hyperboreus) is endemic to Alaska, breeds solely on the remote and uninhabited St. Matthew and Hall islands (332 km2) in the central Bering Sea, and is designated as a species of high conservation concern due to its small population size and restricted range. A previous...

The type locality for the upper Oligocene Nuwok Member of the Sagavanirktok Formation (Carter Creek, North Slope, Alaska, USA) contains abundant occurrence of glendonite, a pseudomorph after the calcium carbonate mineral ikaite, which typically forms in the shallow subsurface of cold marine sediments....

Deformation along strike-slip plate margins often accumulates within structurally partitioned and rheologically heterogeneous crustal blocks within the plate boundary. In these cases, contrasts in the physical properties and state of juxtaposed crustal blocks may play an important role in accommodation of deformation. Near...

We detected and characterized highly pathogenic avian influenza viruses among hunter-harvested wild waterfowl inhabiting western Alaska during September–October 2022 using a molecular sequencing pipeline applied to RNA extracts derived directly from original swab samples. Genomic characterization of 10 H5 clade 2.3.4.4b avian influenza...

The isotope values of fossil snail shells can be important archives of climate. Here, we present the first carbon (δ13C) and oxygen (δ18O) isotope values of snail shells in interior Alaska to explore changes in vegetation and humidity through the late-glacial period. Snail shell δ13C values were...

ObjectiveSome graylings Thymallus spp. possess an elongated dorsal fin and other morphological traits that can be sexually dimorphic, as demonstrated in the European Grayling T. thymallus. North American Arctic Grayling T. arcticus are assumed to follow these trends, but decisive evidence is lacking. This study aimed to determine whether sexually dimorphic...

Survival estimates are critical components of avian ecology. In well-intentioned efforts to maximize the utility of one's research, survival estimates often derive from data that were not originally collected for survival assessments, and such post hoc analyses may include unintentional biases. We estimated the survival of Whimbrels captured and marked at two...

The Pacific marine heatwave (PMH) of 2014-2016 was an intense, long-lasting environmental disturbance expressed throughout the north Pacific. While dramatic consequences of the PMH on pelagic food webs have been well documented, effects on nearshore food webs, i.e., those based on macroalgae primary productivity, benthic invertebrate intermediate consumers, and specialized...

Arctic marine mammals live in a rapidly changing environment due to the amplified effects of global warming. Pacific walruses (Odobenus rosmarus divergens) have responded to declines in Arctic sea-ice extent by increasingly hauling out on land farther from their benthic foraging habitat. Energy models can be useful for better understanding...

Growth of the Tibetan Plateau, Earth’s broadest and highest elevation collisional system, shapes orographic barriers, reorganizes drainage networks, and influences surface erosion and sediment delivery, whose changes in space and provenance feed back to intracontinental tectonic processes. Studies of interior basins within the...

Acute anomalous ocean warming events, including marine heatwaves (MHWs), have significant effects on reproduction and survival of piscivorous seabirds. Additionally, MHWs have negative effects on seabird fish prey, exacerbating these consequences and resulting in population implications for seabirds. We evaluated the relative body condition of Pacific sand lance Ammodytes personatus,...

Using samples spanning 10-degrees of latitude in Alaska, we provide the first comparative assessment of avian haemosporidia distribution of Arctic Alaska with subarctic host populations for four species of grouse and three species of ptarmigan (Galliformes). We found a high overall prevalence for at least one haemospordian genus (88%; N = 351/400), with spruce grouse (Canachites...

A protracted period (2014-2016) of anomalously warm water in the northeast Pacific Ocean precipitated an extensive die-off of common murres Uria aalge (hereafter ‘murres’) during 2015-2016, accompanied by reduced colony attendance and reproductive success of murres and black-legged kittiwakes Rissa tridactyla (‘kittiwakes’) starting in 2015. Most murres died of starvation following a large-scale...

Makushin stratovolcano, Alaska, produced three, highly explosive, andesitic eruptions between ~ 9292 and 6215 yBP. Those eruptions are informally named the CFE (“crater-forming eruption”), Nateekin, and Driftwood Pumice, and they deposited significant tephra fallout in the present-day port of Dutch Harbor and City of Unalaska area. The focus of this study is to examine...

A major goal of volcano monitoring is the rapid identification of volcanic explosions and subsequent warning of associated hazards. Between 1988 and 2016 the Alaska Volcano Observatory (AVO) responded to at least 54 separate volcanic eruptions. During this period, AVO's monitoring program relied principally on seismic and satellite remote sensing...

Polar bears (Ursus maritimus) are threatened by sea-ice loss due to climate change, which is concurrently opening the Arctic to natural resource extraction and a broader scope of national security responsibilities. Mitigating the risk of human–bear conflicts is an emerging challenge as many polar bears spend longer ice-free...

Females must continually make resource allocation decisions because of fitness trade-offs between self-maintenance and investment in current offspring, yet factors underpinning these decisions are unresolved. Polar bears Ursus maritimus face considerable allocation challenges when seasonal sea-ice melt precludes access to prey for several months, and females rely solely on energy stores...

Mass mortality events provide valuable insight into biological extremes and also ecological interactions more generally. The sea star wasting epidemic that began in 2013 catalyzed study of the microbiome, genetics, population dynamics, and community ecology of several high-profile species inhabiting the northeastern...

Innovations in geodesy enable widespread analysis of glacier surface elevation change and geodetic mass balance. However, coincident glacier area data are less widely available, causing inconsistent handling of glacier area change. Here we quantify the bias introduced into meters water equivalent (m w.e.) specific geodetic mass balance...

BackgroundSite fidelity, the tendency to return to a previously visited site, is commonly observed in migratory birds. This behaviour would be advantageous if birds returning to the same site, benefit from their previous knowledge about local resources. However, when habitat quality declines at a site over time, birds...

We assessed habitat suitability for salmonids across selected tributaries upstream from three hydroelectric dams on the upper Skagit River in Whatcom County, northern Washington. We used NetMap, a commercial toolset within the ArcMap geographic information system (GIS), to analyze stream attributes based upon a synthetic stream channel network derived from...

Extensive, detailed information on the spatial distribution of active layer thickness (ALT) in northern Alaska and how it evolves over time could greatly aid efforts to assess the effects of climate change on the region and also help to quantify greenhouse gas emissions generated due to permafrost...