Search for: All records

Abstract Each year, hundreds of international researchers enter Greenland to conduct scientific fieldwork. Historically, they have had little interaction with local communities and scientists at Greenland research institutes. Recognising that collaboration between Greenland and the United States can yield better research, consider more diverse perspectives, articulate the benefits of research to Greenland society, and train the next generation in a collaborative framework, representatives from both countries have been engaged in a series of events to cultivate bilateral relationships. Here, we describe the process of these events (workshops, conference sessions, and public dialogues), the findings, and the outcomes that have followed. Prior to this focused engagement, United States and Greenland scientists typically pursued their research independently. Since the engagement, more researchers from both countries have successfully partnered to obtain funding for collaborative research. Furthermore, development of a bilateral collaboration network is underway. The focused approach on bilateral engagement also proved essential for maintaining research and other activities during the global pandemic. When United States researchers were prevented from entering Greenland, their Greenland partners were able to continue the fieldwork, ensuring that progress was not lost. Future international projects can build on these successes to expand collaborative and interdisciplinary research in Greenland. 

Abstract. Since the 1960s, a deep groundwater system in Wright Valley, Antarctica, has been the hypothesized source of brines to hypersaline Don Juan Pond and Lake Vanda, both of which are rich in calcium and chloride. Modeling studies do not support other possible mechanisms, such as evaporative processes, that could have led to the current suite of ions present in both waterbodies. In 2011 and 2018, an airborne electromagnetic survey was flown over Wright Valley to map subsurface resistivity (down to 600 m) in exploration of liquid water. The surveys revealed widespread unfrozen brine in the subsurface near Lake Vanda, Don Juan Pond, and the North Fork of Wright Valley. While our geophysical survey can neither confirm nor deny deep groundwater connectivity between Lake Vanda and Don Juan Pond, it does point to the potential for deep valley-wide brine, likely within the Ferrar Dolerite formation. 

SUMMARY Airborne electromagnetics (EM) is a geophysical tool well suited to mapping glacial and hydrogeological structures in polar environments. This non-invasive method offers significant spatial coverage without requiring access to the ground surface, enabling the mapping of geological units to hundreds of metres depth over highly varied terrain. This method shows great potential for large-scale surveys in polar environments, as common targets such as permafrost, ice and brine-rich groundwater systems in these settings can be easily differentiated because of their significant contrasts in electrical properties. This potential was highlighted in a 2011 airborne EM survey in the McMurdo Dry Valleys that mapped the existence of a large-scale regional groundwater system in Taylor Valley. A more comprehensive airborne EM survey was flown in November 2018 to broadly map potential groundwater systems throughout the region. Data collected in this survey displayed significant perturbations from a process called induced polarization (IP), an effect that can greatly limit or prevent traditional EM workflows from producing reliable geological interpretations. Here, we present several examples of observed IP signatures over a range of conditions and detail how workflows explicitly designed to handle IP effects can produce reliable geological interpretations and data fits in these situations. Future polar EM surveys can be expected to encounter strong IP effects given the likely presence of geological materials (e.g. ice and permafrost) that can accentuate the influence of IP. 

Abstract. Previous studies of the lakes of the McMurdo Dry Valleys haveattempted to constrain lake level history, and results suggest the lakeshave undergone hundreds of meters of lake level change within the last20 000 years. Past studies have utilized the interpretation of geologicdeposits, lake chemistry, and ice sheet history to deduce lake levelhistory; however a substantial amount of disagreement remains between thefindings, indicating a need for further investigation using new techniques.This study utilizes a regional airborne resistivity survey to provide novelinsight into the paleohydrology of the region. Mean resistivity mapsrevealed an extensive brine beneath the Lake Fryxell basin, which isinterpreted as a legacy groundwater signal from higher lake levels in thepast. Resistivity data suggest that active permafrost formation has beenongoing since the onset of lake drainage and that as recently as 1500–4000 years BP, lake levels were over 60 m higher than present. This coincideswith a warmer-than-modern paleoclimate throughout the Holocene inferred bythe nearby Taylor Dome ice core record. Our results indicate Mid to LateHolocene lake level high stands, which runs counter to previous researchfinding a colder and drier era with little hydrologic activity throughoutthe last 5000 years. 

Organisms that undergo a shift in ontogeny and habitat type often change their spatial distribution throughout their life cycle, but how this affects population dynamics remains poorly understood.

We examined spatial and temporal patterns inAedes nigripesabundance, a widespread univoltine Arctic mosquito species (Diptera: Culicidae), hypothesizing that the spatial distribution of adults would be closely tied to aquatic habitat.

We tracked adult densities ofA. nigripesnear Kangerlussuaq, Greenland using emergence traps, CO₂‐baited traps, and sweep‐nets.

In back‐to‐back years of sampling (2017 and 2018) we found two‐fold variation in overall abundance.

Adults were spatially patchy when first emerging from aquatic habitats but within a week, mean capture rates for host‐seeking adult females were similar across locations, even in places far from larval habitat.

Daily variation in mosquito captures was primarily explained by weather, with virtually no mosquito activity when temperatures averaged less than 8°C or wind speeds exceeded 6 m/s. Gravid females (3% of resting adults) were spatially patchy on the landscape, but not always in the same places where most adults emerged.

The spatial distribution of adults is quickly uncoupled from the spatial distribution of larvae becauseA. nigripesfemales may disperse far from their natal habitats in search of a blood‐meal and high‐quality oviposition habitat.

8. This research highlights the value of studying ecological processes that act at disparate life stages for understanding the population biology of organisms with complex life cycles.

 

Over the past decade, the Arctic has warmed by 0.75°C, far outpacing the global average, while Antarctic temperatures have remained comparatively stable. As Earth approaches 2°C warming, the Arctic and Antarctic may reach 4°C and 2°C mean annual warming, and 7°C and 3°C winter warming, respectively. Expected consequences of increased Arctic warming include ongoing loss of land and sea ice, threats to wildlife and traditional human livelihoods, increased methane emissions, and extreme weather at lower latitudes. With low biodiversity, Antarctic ecosystems may be vulnerable to state shifts and species invasions. Land ice loss in both regions will contribute substantially to global sea level rise, with up to 3 m rise possible if certain thresholds are crossed. Mitigation efforts can slow or reduce warming, but without them northern high latitude warming may accelerate in the next two to four decades. International cooperation will be crucial to foreseeing and adapting to expected changes.