scholarly journals Density, snow, and seasonality lead to variation in muskox (Ovibos moschatus) habitat selection during summer

2019 ◽  
Vol 97 (11) ◽  
pp. 997-1003
Author(s):  
Orlando Tomassini ◽  
Floris M. van Beest ◽  
Niels M. Schmidt
Keyword(s):  
Population Dynamics ◽  
Habitat Selection ◽  
Environmental Conditions ◽  
Census Data ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Selection Strategy ◽  
Ovibos Moschatus ◽  
Arctic Summer

Understanding how environmental conditions influence habitat selection and suitability of free-ranging animals is critical, as the outcome may have implications for individual fitness and population dynamics. Density and snow are among the most influential environmental conditions driving habitat-selection patterns of northern ungulates. We used two decades of census data from high Arctic Greenland to quantify inter- and intra-annual variations in muskox (Ovibos moschatus (Zimmermann, 1780)) habitat selection and suitability during the Arctic summer (July through October). Across years, habitat selection varied considerably, and the strength of habitat selection appeared negatively related to both muskox density and spring snow cover. In early summer, habitat suitability was high and spatially rather uniform. Towards the autumn, suitable habitats contracted to just the lower elevations, when muskoxen exhibited increasingly stronger habitat selection towards low elevations and dense vegetation. This selection strategy clearly reflects the need to build up fat reserves for the upcoming winter, highlighting the energetic importance of the Arctic summer. Extreme climatic events such as freezing rain in autumn are increasing in frequency in Greenland and limit muskox access to high-quality forage in fens. Such events may therefore negatively affect the energy acquisition process of muskox with potential cascading consequences on population dynamics.

Life cycles and population dynamics of enchytraeids (Oligochaeta) from the High Arctic

2000 ◽  
Vol 78 (12) ◽  
pp. 2079-2086 ◽  
Author(s):  
T Birkemoe ◽  
S J Coulson ◽  
L Sømme
Keyword(s):  
Population Dynamics ◽  
High Arctic ◽  
Early Summer ◽  
Life Cycles ◽  
The Arctic ◽  
Adult Size ◽  
Numerous Species ◽  
Summer Temperatures ◽  
First Time ◽  
Mature Size

We report the results of the first study of the population dynamics and life cycles of Arctic enchytraeid populations. Sampling was undertaken in a Salix heath in Adventdalen, Svalbard, during one summer and the succeeding spring. In addition, a Cassiope heath at a more northerly site close to Ny-Ålesund, Svalbard, was sampled twice. The Arctic enchytraeids were generally smaller at maturity than their temperate-zone relatives. The three most numerous species in the Salix heath, Henlea perpusilla, Henlea glandulifera, and Bryodrilus parvus, hatched from cocoons in early summer and attained adult size early in their second summer. A few H. perpusilla and H. glandulifera reached mature size in their first summer; since the summer of investigation was unusually cold, these species may have a 1-year life cycle in warmer years. Life cycles were apparently longer in the Cassiope heath than in the Salix heath. Henlea perpusilla, H. glandulifera, and B. parvus produced eggs throughout the summer in the Salix heath, though hatching was restricted to early summer. Therefore, the hypothesis that cocoons require a cold period to hatch was tested in a laboratory experiment. When soil containing cocoons was incubated at -5°C for 3 weeks, a significant increase in juveniles was demonstrated for H. perpusilla and Bryodrilus diverticulatus compared with soils kept at constant summer temperatures. This is the first time that breaking of dormancy by an external stimulus has been demonstrated in enchytraeid cocoons.

scholarly journals Arctic tidal characteristics at Eureka (80° N, 86° W) and Svalbard (78° N, 16° E) for 2006/07: seasonal and longitudinal variations, migrating and non-migrating tides

2009 ◽  
Vol 27 (3) ◽  
pp. 1153-1173 ◽  
Author(s):  
A. H. Manson ◽  
C. E. Meek ◽  
T. Chshyolkova ◽  
X. Xu ◽  
T. Aso ◽  
...  
Keyword(s):  
High Arctic ◽  
Early Summer ◽  
Planetary Waves ◽  
Diurnal Tide ◽  
The Arctic ◽  
Meteor Radar ◽  
Atmospheric Propagation ◽  
Wave Numbers ◽  
The Antarctic ◽  
Abstract Operation

Abstract. Operation of a Meteor Radar at Eureka, Ellesmere Island (80° N, 86° W) began in February 2006. The first 12 months of wind data (82–97 km) are combined with winds from the Adventdalen, Svalbard Island (78° N, 16° E) Meteor Radar to provide the first contemporaneous longitudinally spaced observations of mean winds, tides and planetary waves at such high Arctic latitudes. Unique polar information on diurnal non-migrating tides (NMT) is provided, as well as complementary information to that existing for the Antarctic on the semidiurnal NMT. Zonal and meridional monthly mean winds differed significantly between Canada and Norway, indicating the influence of stationary planetary waves (SPW) in the Arctic mesopause region. Both diurnal (D) and semi-diurnal (SD) winds also demonstrated significantly different magnitudes at Eureka and Svalbard. Typically the D tide was larger at Eureka and the SD tide was larger at Svalbard. Tidal amplitudes in the Arctic were also generally larger than expected from extrapolation of high mid-latitude data. For example time-sequences from ~90 km showed D wind oscillations at Eureka of 30 m/s in February–March, and four day bursts of SD winds at Svalbard reached 40 m/s in June 2006. Fitting of wave numbers for the migrating and non-migrating tides (MT, NMT) successfully determines dominant tides for each month and height. For the diurnal tide, NMT with s=0, +2 (westward) dominate in non-summer months, while for the semi-diurnal tide NMT with s=+1, +3 occur most often during equinoctial or early summer months. These wave numbers are consistent with stationary planetary wave (SPW)-tidal interactions. Assessment of the global topographic forcing and atmospheric propagation of the SPW (S=1, 2) suggests these winter waves of the Northern Hemisphere are associated with the 78–80° N diurnal NMT, but that the SPW of the Southern Hemisphere winter have little influence on the summer Arctic tidal fields. In contrast the large SPW and NMT of the Arctic winter may be associated, consistent with Antarctic observations, with the observed occurrence of the semidiurnal NMT in the Antarctic summer.

scholarly journals Dynamics of gaseous oxidized mercury at Villum Research Station during the High Arctic summer

2021 ◽  
Vol 21 (17) ◽  
pp. 13287-13309
Author(s):  
Jakob Boyd Pernov ◽  
Bjarne Jensen ◽  
Andreas Massling ◽  
Daniel Charles Thomas ◽  
Henrik Skov
Keyword(s):  
General Pattern ◽  
Ground Level ◽  
High Arctic ◽  
Atmospheric Mercury ◽  
The Arctic ◽  
Research Station ◽  
Cold Temperatures ◽  
Air Masses ◽  
Arctic Summer ◽  
Gaseous Oxidized Mercury

Abstract. While much research has been devoted to the subject of gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Arctic spring during atmospheric mercury depletion events, few studies have examined the behavior of GOM in the High Arctic summer. GOM, once deposited and incorporated into the ecosystem, can pose a threat to human and wildlife health, though there remain large uncertainties regarding the transformation, deposition, and assimilation of mercury into the food web. Therefore, to further our understanding of the dynamics of GOM in the High Arctic during the late summer, we performed measurements of GEM and GOM, along with meteorological parameters and atmospheric constituents, and utilized modeled air mass history during two summer campaigns in 2019 and 2020 at Villum Research Station (Villum) in northeastern Greenland. Seven events of enhanced GOM concentrations were identified and investigated in greater detail. In general, the common factors associated with event periods at ground level were higher levels of radiation and lower H2O mixing ratios, accumulated precipitation, and relative humidity (RH), although none were connected with cold temperatures. Non-event periods at ground level each displayed a different pattern in one or more parameters when compared to event periods. Generally, air masses during event periods for both campaigns were colder and drier, arrived from higher altitudes, and spent more time above the mixed layer and less time in a cloud compared to non-events, although some events deviated from this general pattern. Non-event air masses displayed a different pattern in one or more parameters when compared to event periods, although they were generally warmer and wetter and arrived from lower altitudes with little radiation. Coarse-mode aerosols were hypothesized to provide the heterogenous surface for halogen propagation during some of the events, while for others the source is unknown. While these general patterns were observed for event and non-event periods, analysis of individual events showed more specific origins. Five of the seven events were associated with air masses that experienced similar conditions: transported from the cold, dry, and sunlit free troposphere. However, two events experienced contrasting conditions, with air masses being warm and wet with surface layer contact under little radiation. Two episodes of extremely high levels of NCoarse and BC, which appear to originate from flaring emissions in Russia, did not contribute to enhanced GOM levels. This work aims to provide a better understanding of the dynamics of GOM during the High Arctic summer.

scholarly journals Taxonomic, temporal, and spatial variation in the dynamics of High-Arctic arthropod populations

2020 ◽  
Author(s):  
Toke T. Høye ◽  
Sarah Loboda ◽  
Amanda M. Koltz ◽  
Mark A. K. Gillespie ◽  
Joseph J. Bowden ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Temporal Trends ◽  
Monitoring Program ◽  
High Arctic ◽  
The Arctic ◽  
Taxonomic Resolution ◽  
Ecosystem Functions ◽  
Series Data ◽  
Global Changes ◽  
Apparent Lack

ABSTRACTTime-series data on arthropod populations are critical for understanding the magnitude, direction, and drivers of abundance changes. However, most arthropod monitoring programs are short-lived and limited in taxonomic resolution and spatial extent. Consequently, variation in population dynamics among taxa and habitats remains poorly understood. Monitoring data from the Arctic are particularly underrepresented, yet important to assessments of species abundance changes because many anthropogenic drivers of change that are present in other regions are absent in polar regions. Here, we utilise 24 years of abundance data from Zackenberg in High-Arctic Greenland, which is the longest running Arctic arthropod monitoring program, to study temporal trends in abundance. Despite a strong warming signal in air temperature, we only find evidence of weak temporal trends in arthropod abundances across most taxa. These trends are more pronounced in the most recent decade, with change point analyses suggesting distinct non-linear dynamics within some functional groups such as predators and detritivores. Although the abundances of many taxa were correlated, we detected both positive and negative correlations, suggesting that multiple processes are affecting arthropod populations even in this relatively simple Arctic food web. Finally, we found clear differences among species within single families of arthropods, indicating that an apparent lack of change in abundance at broader taxonomic or functional levels could mask substantial species-specific trends. Our results reiterate the need for more basic research into the life-history, ecology, and adaptation of arthropod species to better understand their sensitivity to global changes.Significance statementTerrestrial arthropods, including insects and spiders, serve critical ecosystem functions and are excellent indicators of environmental change due to their physiology, short generation time, and abundance. The Arctic, with its rapid climate change and limited direct anthropogenic impact, is ideal for examining arthropod population dynamics. We use the most comprehensive, standardized dataset available on Arctic arthropods to evaluate the variability in population dynamics for the most common arthropod groups at various taxonomic levels across 24 years. Our results highlight that temporal trends of arthropod populations seem less directional in the Arctic than in temperate regions. Although abundances of some arthropod taxa are declining, particularly in recent decades, population trends still display high variation among time periods, taxa, and habitats.

scholarly journals Dynamics of gaseous oxidized mercury at Villum Research Station during the High Arctic summer

2021 ◽  
Author(s):  
Jakob Boyd Pernov ◽  
Bjarne Jensen ◽  
Andreas Massling ◽  
Daniel Charles Thomas ◽  
Henrik Skov
Keyword(s):  
Meteorological Data ◽  
High Arctic ◽  
Atmospheric Mercury ◽  
The Arctic ◽  
Research Station ◽  
Cold Temperatures ◽  
Air Mass ◽  
Back Trajectories ◽  
Arctic Summer ◽  
Gaseous Oxidized Mercury

Abstract. While much research has been devoted to the subject of gaseous elemental mercury (GEM) and gaseous oxidized mercury (GOM) in the Arctic spring, during atmospheric mercury depletion events, few studies have examined the behavior of GOM in the High Arctic summer. GOM, once introduced into the ecosystem, can pose a threat to human and wildlife health, though there remain large uncertainties regarding the transformation, deposition, and assimilation of mercury into the ecosystem. Therefore, to further our understanding of the dynamics of gaseous oxidized mercury in the High Arctic during the late summer, we performed measurements of GEM and GOM along with meteorological parameters, atmospheric constituents, and air mass history during two summer campaigns in 2019 and 2020 at Villum Research Station (Villum) in Northeastern Greenland. Five events of enhanced GOM concentrations were identified and investigated in greater detail. The origin of these events was identified, through analysis of air mass back-trajectories, associated meteorological data, and other atmospheric constituents, to be the cold, dry free troposphere. These events were associated with low RH, limited precipitation, cold temperatures, and intense sunlight along the trajectory path. Events were positively correlated with ozone, aerosol particle number, and black carbon mass concentration, which were interpreted as an indication of tropospheric air masses. This work aims to provide a better understanding of the dynamics of GOM during the High Arctic summer.

scholarly journals The Effect of Downwelling Longwave and Shortwave Radiation on Arctic Summer Sea Ice

2016 ◽  
Vol 29 (3) ◽  
pp. 1143-1159 ◽  
Author(s):  
Marie-Luise Kapsch ◽  
Rune Grand Graversen ◽  
Michael Tjernström ◽  
Richard Bintanja
Keyword(s):  
Sea Ice ◽  
Early Summer ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Atmospheric Conditions ◽  
Sea Ice Extent ◽  
Climate Fluctuations ◽  
Ice Melt ◽  
Different Seasons ◽  
Arctic Summer

Abstract The Arctic summer sea ice has diminished fast in recent decades. A strong year-to-year variability on top of this trend indicates that sea ice is sensitive to short-term climate fluctuations. Previous studies show that anomalous atmospheric conditions over the Arctic during spring and summer affect ice melt and the September sea ice extent (SIE). These conditions are characterized by clouds, humidity, and heat anomalies that all affect downwelling shortwave (SWD) and longwave (LWD) radiation to the surface. In general, positive LWD anomalies are associated with cloudy and humid conditions, whereas positive anomalies of SWD appear under clear-sky conditions. Here the effect of realistic anomalies of LWD and SWD on summer sea ice is investigated by performing experiments with the Community Earth System Model. The SWD and LWD anomalies are studied separately and in combination for different seasons. It is found that positive LWD anomalies in spring and early summer have significant impact on the September SIE, whereas winter anomalies show only little effect. Positive anomalies in spring and early summer initiate an earlier melt onset, hereby triggering several feedback mechanisms that amplify melt during the succeeding months. Realistic positive SWD anomalies appear only important if they occur after the melt has started and the albedo is significantly reduced relative to winter conditions. Simulations where both positive LWD and negative SWD anomalies are implemented simultaneously, mimicking cloudy conditions, reveal that clouds during spring have a significant impact on summer sea ice while summer clouds have almost no effect.

scholarly journals High gas-phase mixing ratios of formic and acetic acid in the High Arctic

2018 ◽  
Author(s):  
Emma L. Mungall ◽  
Jonathan P. D. Abbatt ◽  
Jeremy J. B. Wentzell ◽  
Gregory R. Wentworth ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Transport Model ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Chemical Transport Model ◽  
Phase Measurements ◽  
Diurnal Cycles ◽  
Mixing Ratios

Abstract. Formic and acetic acid are ubiquitous and abundant in the Earth's atmosphere and are important contributors to cloud water acidity, especially in remote regions. Their global sources are not well understood, as evidenced by the inability of models to reproduce the magnitude of measured mixing ratios, particularly at high northern latitudes. The scarcity of measurements at those latitudes is also a hindrance to understanding these acids and their sources. Here, we present ground-based gas-phase measurements of formic acid (FA) and acetic acid (AA) in the Canadian Arctic collected at 0.5 Hz with a high resolution chemical ionization time-of-flight mass spectrometer using the iodide reagent ion (Iodide HR-ToF-CIMS, Aerodyne). This study was conducted at Alert, Nunavut, in the early summer of 2016. FA and AA mixing ratios for this period show high temporal variability and occasional excursions to very high values (up to 11 and 40 ppbv respectively). High levels of FA and AA were observed under two very different conditions: under overcast, cold conditions during which physical equilibrium partitioning should not favour their emission, and during warm and sunny periods. During the latter, sunny periods, the FA and AA mixing ratios also displayed diurnal cycles in keeping with a photochemical source near the ground. These observations highlight the complexity of the sources of FA and AA, and suggest that current chemical transport model implementations of the sources of FA and AA in the Arctic may be incomplete.

Role of dimethyl sulfide on the formation and growth of aerosols, and its impact on liquid clouds in the Arctic summer

2020 ◽  
Author(s):  
Roya Ghahreman ◽  
Wanmin Gong ◽  
Ann-Lise Norman ◽  
Stephen R. Beagley ◽  
Ayodeji Akingunola ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Model Simulation ◽  
Cloud Condensation Nuclei ◽  
Cloud Droplet ◽  
Liquid Water Content ◽  
High Arctic ◽  
Cloud Microphysics ◽  
The Arctic ◽  
The Impact ◽  
Arctic Summer

<p>Atmospheric dimethyl sulfide, DMS, is the main biogenic source of sulfate particles in the Arctic atmosphere. Sulfate particles have a net cooling effect, which can partially offset Arctic warming from absorbing aerosols, such as black carbon. As efficient cloud condensation nuclei (CCN), sulfate particles are also able to influence the cloud’s microphysical properties. </p><p>DMS production and emission to the atmosphere increase during the Arctic summer, due to a greater ice-free sea surface area and higher biological activity. In the model simulation of a field campaign conducted over the Canadian high Arctic during the summer of 2014 (NETCARE; Abbatt et al. 2019), the inclusion of DMS in the model, GEM-MACH, resulted in a significant increase, up to 100%, in the modelled atmospheric SO<sub>2</sub> in some regions of the Canadian Arctic. Analysis of the modelled size-segregated aerosol sulfate indicated that DMS has the most significant impact on particles in the size range of 50 – 200 nm in this case. Simulations have shown that localized regions of high seawater DMS can have a significant impact on atmospheric concentrations.</p><p>Further investigation of DMS impact on the Arctic summer cloud microphysics was carried out by using a fully coupled version of GEM-MACH. Overall, the model simulations show that the inclusion of DMS in model leads to an increase in cloud droplet number concentrations (CDNC) and a decrease in droplet mean mass diameters (MMD), and has no significant effects on liquid water content (LWC). The impact of DMS on Canadian weather forecasts will be evaluated using operational forecast tools.</p>

scholarly journals High gas-phase mixing ratios of formic and acetic acid in the High Arctic

2018 ◽  
Vol 18 (14) ◽  
pp. 10237-10254 ◽  
Author(s):  
Emma L. Mungall ◽  
Jonathan P. D. Abbatt ◽  
Jeremy J. B. Wentzell ◽  
Gregory R. Wentworth ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Transport Model ◽  
High Arctic ◽  
Early Summer ◽  
The Arctic ◽  
Chemical Transport Model ◽  
Phase Measurements ◽  
Diurnal Cycles ◽  
Mixing Ratios

Abstract. Formic and acetic acid are ubiquitous and abundant in the Earth's atmosphere and are important contributors to cloud water acidity, especially in remote regions. Their global sources are not well understood, as evidenced by the inability of models to reproduce the magnitude of measured mixing ratios, particularly at high northern latitudes. The scarcity of measurements at those latitudes is also a hindrance to understanding these acids and their sources. Here, we present ground-based gas-phase measurements of formic acid (FA) and acetic acid (AA) in the Canadian Arctic collected at 0.5 Hz with a high-resolution chemical ionization time-of-flight mass spectrometer using the iodide reagent ion (iodide HR-ToF-CIMS, Aerodyne). This study was conducted at Alert, Nunavut, in the early summer of 2016. FA and AA mixing ratios for this period show high temporal variability and occasional excursions to very high values (up to 11 and 40 ppbv respectively). High levels of FA and AA were observed under two very different conditions: under overcast, cold conditions during which physical equilibrium partitioning should not favor their emission, and during warm and sunny periods. During the latter, sunny periods, the FA and AA mixing ratios also displayed diurnal cycles in keeping with a photochemical source near the ground. These observations highlight the complexity of the sources of FA and AA, and suggest that current chemical transport model implementations of the sources of FA and AA in the Arctic may be incomplete.

scholarly journals Exploring the diet of arctic wolves (Canis lupus arctos) at their northern range limit

2018 ◽  
Vol 96 (3) ◽  
pp. 277-281 ◽  
Author(s):  
F. Dalerum ◽  
S. Freire ◽  
A. Angerbjörn ◽  
N. Lecomte ◽  
Å. Lindgren ◽  
...  
Keyword(s):  
Climate Change ◽  
Canis Lupus ◽  
Arctic Region ◽  
High Arctic ◽  
The Arctic ◽  
Frequency Of Occurrence ◽  
Range Limit ◽  
Arctic Ecosystems ◽  
Ovibos Moschatus ◽  
Arctic Hare

The grey wolf (Canis lupus Linnaeus, 1758) is one of the most widespread large carnivores on Earth, and occurs throughout the Arctic. Although wolf diet is well studied, we have scant information from high Arctic areas. Global warming is expected to increase the importance of predation for ecosystem regulation in Arctic environments. To improve our ability to manage Arctic ecosystems under environmental change, we therefore need knowledge about Arctic predator diets. Prey remains in 54 wolf scats collected at three sites in the high Arctic region surrounding the Hall Basin (Judge Daly Promontory, Ellesmere Island, Canada, and Washington Land and Hall Land, both in northwestern Greenland) pointed to a dietary importance of arctic hare (Lepus arcticus Ross, 1819; 55% frequency of occurrence) and muskoxen (Ovibos moschatus (Zimmermann, 1780); 39% frequency of occurrence), although we observed diet variation among the sites. A literature compilation suggested that arctic wolves (Canis lupus arctos Pocock, 1935) preferentially feed on caribou (Rangifer tarandus (Linnaeus, 1758)) and muskoxen, but can sustain themselves on arctic hares and Greenland collared lemmings (Dicrostonyx groenlandicus (Traill, 1823)) in areas with limited or no ungulate populations. We suggest that climate change may alter the dynamics among wolves, arctic hare, muskoxen, and caribou, and we encourage further studies evaluating how climate change influences predator–prey interactions in high Arctic environments.

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