scholarly journals Consumption of CH<sub>3</sub>Cl, CH<sub>3</sub>Br, and CH<sub>3</sub>I and emission of CHCl<sub>3</sub>, CHBr<sub>3</sub>, and CH<sub>2</sub>Br<sub>2</sub> from the forefield of a retreating Arctic glacier

2020 ◽  
Vol 20 (12) ◽  
pp. 7243-7258 ◽  
Author(s):  
Moya L. Macdonald ◽  
Jemma L. Wadham ◽  
Dickon Young ◽  
Chris R. Lunder ◽  
Ove Hermansen ◽  
...  
Keyword(s):  
Methyl Chloride ◽  
High Arctic ◽  
The Arctic ◽  
Emission Rates ◽  
Cyanobacterial Mats ◽  
Small Surface ◽  
Glacier Forefield ◽  
Land Surfaces ◽  
Arctic Glacier ◽  
The Impact

Abstract. The Arctic is one of the most rapidly warming regions of the Earth, with predicted temperature increases of 5–7 ∘C and the accompanying extensive retreat of Arctic glacial systems by 2100. Retreating glaciers will reveal new land surfaces for microbial colonisation, ultimately succeeding to tundra over decades to centuries. An unexplored dimension to these changes is the impact upon the emission and consumption of halogenated organic compounds (halocarbons). Halocarbons are involved in several important atmospheric processes, including ozone destruction, and despite considerable research, uncertainties remain in the natural cycles of some of these compounds. Using flux chambers, we measured halocarbon fluxes across the glacier forefield (the area between the present-day position of a glacier's ice-front and that at the last glacial maximum) of a high-Arctic glacier in Svalbard, spanning recently exposed sediments (<10 years) to approximately 1950-year-old tundra. Forefield land surfaces were found to consume methyl chloride (CH3Cl) and methyl bromide (CH3Br), with both consumption and emission of methyl iodide (CH3I) observed. Bromoform (CHBr3) and dibromomethane (CH2Br2) have rarely been measured from terrestrial sources but were here found to be emitted across the forefield. Novel measurements conducted on terrestrial cyanobacterial mats covering relatively young surfaces showed similar measured fluxes to the oldest, vegetated tundra sites for CH3Cl, CH3Br, and CH3I (which were consumed) and for CHCl3 and CHBr3 (which were emitted). Consumption rates of CH3Cl and CH3Br and emission rates of CHCl3 from tundra and cyanobacterial mat sites were within the ranges reported from older and more established Arctic tundra elsewhere. Rough calculations showed total emissions and consumptions of these gases across the Arctic were small relative to other sources and sinks due to the small surface area represented by glacier forefields. We have demonstrated that glacier forefields can consume and emit halocarbons despite their young age and low soil development, particularly when cyanobacterial mats are present.

scholarly journals The Rossby radius in the Arctic Ocean

Ocean Science ◽  
2014 ◽  
Vol 10 (6) ◽  
pp. 967-975 ◽  
Author(s):  
A. J. G. Nurser ◽  
S. Bacon
Keyword(s):  
Arctic Ocean ◽  
General Circulation ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
High Arctic ◽  
The Arctic ◽  
Hudson Bay ◽  
Ocean Eddies ◽  
Shelf Seas ◽  
The Impact

Abstract. The first (and second) baroclinic deformation (or Rossby) radii are presented north of ~60° N, focusing on deep basins and shelf seas in the high Arctic Ocean, the Nordic seas, Baffin Bay, Hudson Bay and the Canadian Arctic Archipelago, derived from climatological ocean data. In the high Arctic Ocean, the first Rossby radius increases from ~5 km in the Nansen Basin to ~15 km in the central Canadian Basin. In the shelf seas and elsewhere, values are low (1–7 km), reflecting weak density stratification, shallow water, or both. Seasonality strongly impacts the Rossby radius only in shallow seas, where winter homogenization of the water column can reduce it to below 1 km. Greater detail is seen in the output from an ice–ocean general circulation model, of higher resolution than the climatology. To assess the impact of secular variability, 10 years (2003–2012) of hydrographic stations along 150° W in the Beaufort Gyre are also analysed. The first-mode Rossby radius increases over this period by ~20%. Finally, we review the observed scales of Arctic Ocean eddies.

Late 20th century increase in northern Svalbard glacier-derived runoff tracked by encrusting coralline algae

2020 ◽  
Author(s):  
Steffen Hetzinger ◽  
Jochen Halfar ◽  
Zoltan Zajacz ◽  
Marco Möller ◽  
Max Wisshak
Keyword(s):  
Global Warming ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
High Arctic ◽  
Climate System ◽  
Coralline Algae ◽  
The Arctic ◽  
Surface Ocean ◽  
The Impact ◽  
Arctic Surface

&lt;p&gt;The Arctic cryosphere is changing at a rapid pace due to global warming and the large-scale changes observed in the Arctic during the past decades exert a strong influence throughout the global climate system. The warming of Arctic surface air temperatures is more than twice as large as the global average over the last two decades and recent events indicate new extremes in the Arctic climate system, e.g. for the last five years Arctic annual surface air temperature exceeded that of any year since 1900 AD. Northern Spitsbergen, Svalbard, located in the High Arctic at 80&amp;#176;N, is a warming hotspot with an observed temperature rise of ~6&amp;#176;C over the last three decades indicating major global warming impacts. However, even the longest available datasets on Svalbard climatic conditions do not extend beyond the 1950s, inhibiting the study of long-term natural variability before anthropogenic influence. Ongoing climate trends strongly affect the state of both glaciers and seasonal snow in Svalbard. Modeled data suggest a marked increase in glacier runoff during recent decades in northern Svalbard. However, observational data are sparse and short and the potential effects on the surface ocean are unclear.&lt;br&gt;This study focuses on the ultra-high-resolution analysis of calcified coralline algal buildups growing attached to the shallow seafloor along Arctic coastlines. Analysis of these new annually-layered climate archives is based on the long-lived encrusting coralline algae &lt;em&gt;Clathromorphum compactum&lt;/em&gt;, providing a historic perspective on recently observed changes. Here, we present a 200-year record of past surface ocean variability from Mosselbukta, Spitsbergen, northern Svalbard. By using algal Ba/Ca ratios as a proxy for past glacier-derived meltwater input, we investigate past multi-decadal-scale fluctuations in land-based freshwater contributions to the ocean surface layer. Our records, based on multiple coralline algal specimens, show a strong and statistically significant increasing trend in algal Ba/Ca ratios from the 1990s onwards, suggesting a drastic increase in land-based runoff at Mosselbukta. The drastic rate of increase is unprecedented during the last two centuries, directly capturing the impact of amplified surface air temperature warming on coastal high Arctic surface ocean environments.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along two years (2011–2012) of field campaign

2016 ◽  
Author(s):  
Luca Ferrero ◽  
David Cappelletti ◽  
Maurizio Busetto ◽  
Mauro Mazzola ◽  
Angelo Lupi ◽  
...  
Keyword(s):  
Size Distribution ◽  
Black Carbon ◽  
High Arctic ◽  
Aerosol Concentration ◽  
The Arctic ◽  
Aerosol Size Distribution ◽  
Vertical Profiles ◽  
Anthropogenic Aerosol ◽  
Haze Pollution ◽  
The Impact

Abstract. In this paper we present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011–2012) and resulted in 200 vertical profiles measured during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground to put on a firmer grounds the analysis of the vertical profiles. The collected experimental data allowed a classification of the vertical profiles into different typologies which allowed to describe a seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behaviour was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude in function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the summer Arctic affecting the climate.

scholarly journals Distribution of soil nitrogen and nitrogenase activity in the forefield of a High Arctic receding glacier

2018 ◽  
Vol 59 (77) ◽  
pp. 87-94 ◽  
Author(s):  
Thomas Turpin-Jelfs ◽  
Katerina Michaelides ◽  
Joshua J. Blacker ◽  
Liane G. Benning ◽  
James M. Williams ◽  
...  
Keyword(s):  
Nitrogenase Activity ◽  
Soil Formation ◽  
High Arctic ◽  
N Fixation ◽  
N Availability ◽  
N Accumulation ◽  
Glacier Forefield ◽  
Biological N Fixation ◽  
Arctic Glacier ◽  
Emerging Ecosystems

ABSTRACTGlaciers retreating in response to climate warming are progressively exposing primary mineral substrates to surface conditions. As primary production is constrained by nitrogen (N) availability in these emerging ecosystems, improving our understanding of how N accumulates with soil formation is of critical concern. In this study, we quantified how the distribution and speciation of N, as well as rates of free-living biological N fixation (BNF), change along a 2000-year chronosequence of soil development in a High Arctic glacier forefield. Our results show the soil N pool increases with time since exposure and that the rate at which it accumulates is influenced by soil texture. Further, all N increases were organically bound in soils which had been ice-free for 0–50 years. This is indicative of N limitation and should promote BNF. Using the acetylene reduction assay technique, we demonstrated that microbially mediated inputs of N only occurred in soils which had been ice-free for 0 and 3 years, and that potential rates of BNF declined with increased N availability. Thus, BNF only supports N accumulation in young soils. When considering that glacier forefields are projected to become more expansive, this study has implications for understanding how ice-free ecosystems will become productive over time.

scholarly journals Consumption of CH<sub>3</sub>Cl, CH<sub>3</sub>Br and CH<sub>3</sub>I and emission of CHCl<sub>3</sub>, CHBr<sub>3</sub> and CH<sub>2</sub>Br<sub>2</sub> from a retreating Arctic glacier's forefield

2019 ◽  
Author(s):  
Moya L. Macdonald ◽  
Jemma L. Wadham ◽  
Dickon Young ◽  
Chris R. Lunder ◽  
Ove Hermansen ◽  
...  
Keyword(s):  
Organic Compounds ◽  
The Arctic ◽  
Halogenated Organic Compounds ◽  
Atmospheric Processes ◽  
Ozone Destruction ◽  
The Earth ◽  
Considerable Research ◽  
Land Surfaces ◽  
The Impact ◽  
Natural Cycles

Abstract. The Arctic is one of the most rapidly warming regions of the Earth, with predicted temperature increases of 5–7 °C and the accompanying extensive retreat of Arctic glacial systems by 2100. This will reveal new proglacial land surfaces for microbial colonisation, ultimately succeeding to tundra over decades to centuries. An unexplored dimension to these changes is the impact upon the emission and consumption of halogenated organic compounds (halocarbons) from proglacial land surfaces. Halocarbons are involved in several important atmospheric processes, including ozone destruction, and despite considerable research, uncertainties remain in the natural cycles of some of these compounds. Using flux chambers, we measured halocarbon fluxes from proglacial land surfaces spanning recently-exposed sediments (

scholarly journals Transfer of organic Br and Cl from the Biosphere to the Atmosphere during the Cretaceous/Tertiary Impact: Implications for the stratospheric Ozone Layer

2004 ◽  
Vol 4 (5) ◽  
pp. 6769-6787 ◽  
Author(s):  
K. Kourtidis
Keyword(s):  
Biomass Burning ◽  
Stratospheric Ozone ◽  
Methyl Chloride ◽  
Ozone Layer ◽  
Emission Rates ◽  
Mixing Ratios ◽  
Wide Range ◽  
Order Of Magnitude ◽  
The Impact ◽  
Terrestrial Biomass

Abstract. Following the Cretaceous/Tertiary (K/T) meteoritic impact some 65 Myr ago, large portions of aboveground terrestrial biomass were burned. As a result, large amounts of various trace gases were injected to the atmosphere, inducing a wide range of effects on climate and ecosystems. Here, it is commented on the previously unaccounted emission to the atmosphere of methyl bromide (CH3Br) and methyl chloride (CH3Cl) from extensive biomass burning that followed the impact. Based on reported biomass burning emission rates of the above organohalogens relative to CO2, it is estimated that their emissions from global fires resulted in tropospheric mixing ratios of around 20–65.8 ppbv organic Cl and 110–390 pptv organic Br. The above calculated mixing ratios of active chlorine and bromine are more than an order of magnitude their present, anthropogenically perturbed level and, although the ocean ultimately might absorb them, we argue here that they could still remain in the stratosphere for many years, substantially affecting the ozone layer. This would have lead to very serious increases in short wavelength UV radiation reaching the lowermost atmosphere.

scholarly journals Impact of vessel traffic on the home ranges and movement of shorthorn sculpin (Myoxocephalus scorpius) in the nearshore environment of the high Arctic

2018 ◽  
Vol 75 (12) ◽  
pp. 2390-2400 ◽  
Author(s):  
Silviya V. Ivanova ◽  
Steven T. Kessel ◽  
Justin Landry ◽  
Caitlin O’Neill ◽  
Montana F. McLean ◽  
...  
Keyword(s):  
Acoustic Telemetry ◽  
Open Water ◽  
High Arctic ◽  
The Arctic ◽  
Environmental Drivers ◽  
Home Ranges ◽  
Shorthorn Sculpin ◽  
Arctic Fish ◽  
Myoxocephalus Scorpius ◽  
The Impact

Sea ice reduction in the Arctic is allowing for increased vessel traffic and activity. Vessel noise is a known anthropogenic disturbance, but its effects on Arctic fish are largely unknown. Using acoustic telemetry — Vemco positioning system — we quantified the home ranges and fine-scale movement types (MT) of shorthorn sculpin (Myoxocephalus scorpius), a common benthic Arctic fish, in response to vessels and environmental drivers during open water over 3 years (2012–2014). Low overlap of core home ranges (50%) for all years and a change of overall MT proportions (significant in 2012 only) were observed when vessels were present compared with absent. However, changes in MTs associated with vessel presence were not consistent between years. Photoperiod was the only environmental driver that influenced (R2 = 0.32) MTs of sculpin. This is the first study of vessel impacts on Arctic fish using acoustic telemetry and demonstrates that individuals alter their behavior and home ranges when vessels are present. Given increasing vessel traffic in the Arctic, additional study on the impact of vessels on these ecosystems is warranted.

scholarly journals Late twentieth century increase in northern Spitsbergen (Svalbard) glacier-derived runoff tracked by coralline algal Ba/Ca ratios

2021 ◽  
Author(s):  
Steffen Hetzinger ◽  
Jochen Halfar ◽  
Zoltan Zajacz ◽  
Marco Möller ◽  
Max Wisshak
Keyword(s):  
High Arctic ◽  
Coralline Algae ◽  
The Arctic ◽  
Climate Modelling ◽  
Annual Increment ◽  
Surface Ocean ◽  
Rate Of Increase ◽  
Drastic Increase ◽  
Modelling Studies ◽  
The Impact

AbstractThe Arctic cryosphere is changing rapidly due to global warming. Northern Svalbard is a warming hotspot with a temperature rise of ~ 6 °C over the last three decades. Concurrently, modelled data suggest a marked increase in glacier runoff during recent decades in northern Svalbard, and runoff is projected to increase. However, observational data from before anthropogenic influence are sparse and the potential effects on the surface ocean are unclear. Here, we present a 200-year record of Ba/Ca ratios measured in annual increment-forming coralline algae from northern Spitsbergen as a proxy for past glacier-derived meltwater input. Our record shows a significant increasing trend in algal Ba/Ca ratios from the late-1980s onwards matching modelled regional runoff data, suggesting a drastic increase in land-based runoff. The rate of increase is unprecedented during the last two centuries and captures the impact of amplified warming on the coastal surface ocean in the high Arctic. The algal Ba/Ca runoff proxy offers an opportunity to reconstruct past land-based runoff variability in Arctic settings in high resolution, providing important data for validating and improving climate modelling studies.

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

&lt;p&gt;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&amp;#8217;s microphysical properties.&amp;#160;&lt;/p&gt;&lt;p&gt;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&lt;sub&gt;2&lt;/sub&gt;&amp;#160;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 &amp;#8211; 200 nm in this case. Simulations have shown that localized regions of high seawater DMS can have a significant impact on atmospheric concentrations.&lt;/p&gt;&lt;p&gt;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.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document