Polar Research (E-Journal)
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Measurement of loss rates of organic compounds in snow using in situ experiments and isotopically labelled compounds
No full textOrganic molecular marker compounds are widely used to identify emissions from anthropogenic and biogenic air pollution sources in atmospheric samples and in deposition. Specific organic compounds have been detected in polar regions, but their fate after deposition to snow is poorly characterized. Within this context, a series of exposure experiments were carried out to observe the post-depositional processing of organic compounds under real-world conditions in snow on the surface of the Greenland Ice Sheet, at the Summit research station. Snow was prepared from water spiked with isotopically labelled organic compounds, representative of typical molecular marker compounds emitted from anthropogenic activities. Reaction rate constants and reaction order were determined based on a decrease in concentration to a stable, non-zero, threshold concentration. Fluoranthene-d10, docosane-d46, hexadecanoic acid-d31, docosanoic acid-d43 and azelaic acid-d14 were estimated to have first order loss rates within surface snow with reaction rate constants of 0.068, 0.040, 0.070, 0.067 and 0.047 h-1, respectively. No loss of heptadecane-d36 was observed. Overall, these results suggest that organic contaminants are archived in polar snow, although significant post-depositional losses of specific organic compounds occur. This has implications for the environmental fate of organic contaminants, as well as for ice-core studies that seek to use organic molecular markers to infer past atmospheric loadings, and source emissions.Keywords: Snow; photochemistry; air pollution; Greenland; ArcticTo access the supplementary material to this article: 'Supplementary Figures & Table' and 'Supplementary File', please see Supplementary files in the column to the right (under Article Tools).(Published: 26 July 2012)Citation: Polar Research 2012, 31, 11597, http://dx.doi.org/10.3402/polar.v31i0.1159
Reflection and transmission of irradiance by snow and sea ice in the central Arctic Ocean in summer 2010
No full textReflection and transmission of irradiance by the combined snow and sea ice layer were measured at an ice camp (ca. 10 days) and several short-term stations (ca. 2 h) established in the western sector of the Arctic Ocean above 80°N during the 2010 summer. These measurements were made with an intention to quantify the apparent optical properties of snow and sea ice, and to evaluate their roles in the mass balance of snow-covered sea ice in the High Arctic. The integrated 350–920 nm albedo ranged from 0.54 to 0.88, and was primarily dependent on the geophysical properties of snow, but not those of sea ice. This implies that all snow cover was still optically thick, even though snow melting had commenced at all measurement sites. For sea ice about 1.66 m thick and covered by 2.5–8.5 cm of snow at the ice camp, the integrated 350–920 nm transmittance ranged from 0.017 to 0.065. Rapid snow melting resulting from an event of slight drizzle doubled the available solar irradiance under the ice (from ca. 3.6 toca. 7.2 W·m–2), which further accelerated ice-bottom decay. During the measurement at the camp, the temporally averaged incident solar irradiance at 320–950 nm was 110.6 ± 33.6 W·m–2, 29.2 ± 2.9% of which was absorbed by snow and sea ice and utilized to melt snow and sea ice. The melting of snow and sea ice had a distinctly greater effect on the spectral reflection and transmission for the near-infrared spectrum than for the ultraviolet and visible spectra.Keywords: Sea ice; snow; solar irradiance; reflection; transmission; Arctic(Published: 30 March 2012)Citation: Polar Research 2012, 31, 17325, DOI: 10.3402/polar.v31i0.1732
Feeding grounds of the eastern South Pacific humpback whale population include the South Orkney Islands
No full textThis paper reports on two photo-identified humpback whales (Megaptera novaeangliae) that were sighted in different years in the proximity of the South Orkney Islands, at the boundary between the Scotia and Weddell seas (60o54.5’S – 46o40.4’W and 60o42.6’S – 45o33’W). One of the whales had been previously sighted off Ecuador, a breeding ground for the eastern South Pacific population. The other whale was subsequently resighted in Bransfield Strait, off the western Antarctic Peninsula, a well-documented feeding ground for the same population. These matches give support to a hypothesis that the area south of the South Orkney Islands is occupied by whales from the eastern South Pacific breeding stock. Consequently, we propose 40oW as a new longitudinal boundary between the feeding grounds associated with the eastern South Pacific and western South Atlantic breeding stocks.Keywords: Humpback whale; photo-identification; breeding stocks; migration; South Orkney Islands; Southern Ocean(Published: 20 March 2012)Citation: Polar Research 2012, 31, 17324, DOI: 10.3402/polar.v31i0.1732
Correlative and dynamic species distribution modelling for ecological predictions in the Antarctic: a cross-disciplinary concept
No full textDevelopments of future scenarios of Antarctic ecosystems are still in their infancy, whilst predictions of the physical environment are recognized as being of global relevance and corresponding models are under continuous development. However, in the context of environmental change simulations of the future of the Antarctic biosphere are increasingly demanded by decision makers and the public, and are of fundamental scientific interest. This paper briefly reviews existing predictive models applied to Antarctic ecosystems before providing a conceptual framework for the further development of spatially and temporally explicit ecosystem models. The concept suggests how to improve approaches to relating species’ habitat description to the physical environment, for which a case study on sea urchins is presented. In addition, the concept integrates existing and new ideas to consider dynamic components, particularly information on the natural history of key species, from physiological experiments and biomolecular analyses. Thereby, we identify and critically discuss gaps in knowledge and methodological limitations. These refer to process understanding of biological complexity, the need for high spatial resolution oceanographic data from the entire water column, and the use of data from biomolecular analyses in support of such ecological approaches. Our goal is to motivate the research community to contribute data and knowledge to a holistic, Antarctic-specific, macroecological framework. Such a framework will facilitate the integration of theoretical and empirical work in Antarctica, improving our mechanistic understanding of this globally influential ecoregion, and supporting actions to secure this biodiversity hotspot and its ecosystem services.Keywords: Environmental change; integrative modelling framework; spatially and temporally explicit modelling macroecology; biodiversity; habitat suitability models(Published: 4 May 2012)Citation: Polar Research 2012, 31, 11091, http://dx.doi.org/10.3402/polar.v31i0.11091 To access the supplementary material to this article: Supplementary Tables S1, S2, please see Supplementary Files in the column to the right (under Article Tools)
The impact of human activities on wilderness and aesthetic values in Antarctica
No full textThere has been little progress in implementing protection of wilderness and aesthetic values in Antarctica since the coming into force of the Protocol on Environmental Protection to the Antarctic Treaty in 1998. This can in part be attributed to a lack of research defining these values and showing how they may be assessed. In 2009, a survey comprising 90 images of Antarctic landscapes was established on the Internet to canvass as wide a cross-section of people with an interest in Antarctica as possible on their perceptions of wilderness and their aesthetic preference. At the time of writing, over 337 respondents from 23 nationalities have taken part in the survey. Responses were analysed to determine the effect of human presence, both transient and as infrastructure, on perceptions of wilderness and aesthetic values. The analysis was in three parts: (1) all images combined; (2) images grouped by landscape type, derived from the Environmental Domains of Antarctica regionalization; and (3) 16 pairs of digitally manipulated images of which respondents were shown either an original image or one in which human presence had been either digitally removed or added. Responses to images grouped by landscape type show that coastal and ice-free areas are less valued both aesthetically and as wilderness than mountainous and ice-covered terrains. Signs of human presence were found to make images significantly less likely to be considered as wilderness and also reduced their aesthetic rating. This demonstrates that human impacts on these values are measureable.Keywords: Antarctica; Madrid Protocol; wilderness; aesthetic; values; photographs(Published: 28 December 2012)To access the supplementary material to this article, please see Supplementary Files in the column to the right (under Article Tools)Citation: Polar Research 2012, 31, 10858, http://dx.doi.org/10.3402/polar.v31i0.1085
Culturable heterotrophic bacteria from Potter Cove, Antarctica, and their hydrolytic enzymes production
No full textAffiliations of the dominant culturable bacteria isolated from Potter Cove, South Shetland Islands, Antarctica, were investigated together with their production of cold-active hydrolytic enzymes. A total of 189 aerobic heterotrophic bacterial isolates were obtained at 4°C and sorted into 63 phylotypes based on their amplified ribosomal DNA restriction analysis profiles. The sequencing of the 16S rRNA genes of representatives from each phylotype showed that the isolates belong to the phyla Proteobacteria (classes Alpha- and Gamma-proteobacteria), Bacteroidetes (class Flavobacteria), Actinobacteria (class Actinobacteria) and Firmicutes (class Bacilli). The predominant culturable group in the site studied belongs to the class Gammaproteobacteria, with 65 isolates affiliated to the genus Pseudoalteromonas and 58 to Psychrobacter. Among the 189 isolates screened, producers of amylases (9.5%), pectinases (22.8%), cellulases (14.8%), CM-cellulases (25.4%), xylanases (20.1%) and proteases (44.4%) were detected. More than 25% of the isolates produced at least one extracellular enzyme, with some of them producing up to six of the tested extracellular enzymatic activities. These results suggest that a high culturable bacterial diversity is present in Potter Cove and that this place represents a promising source of biomolecules.Keywords: Microbial enzymes; Antarctic bacteria; marine bacteria; cold enzymes; psychrophiles(Published: 20 December 2012)Citation: Polar Research 2012, 31, 18507, http://dx.doi.org/10.3402/polar.v31i0.1850
Holocene insect remains from south-western Greenland
No full textRemains of plants and invertebrates from Holocene deposits in south-western Greenland include a number of insect fragments from Heteroptera and Coleoptera. Some of the finds extend the known temporal range of the species considerably back in time, and one of the taxa has not previously been found in Greenland either fossil or extant. The fossil fauna includes the weevil Rutidosoma globulus which is at present extremely rare in Greenland. Its rarity might indicate that it is a recent immigrant, but the fossil finds provide a minimum date for its arrival at around 5840 cal. years B.P. Other remains of terrestrial insects complement the scarce fossil Greenland record of the species concerned.Keywords: Greenland; Arctic; Holocene; insects; beetles; palaeoenvironments(Published: 12 June 2012)Citation: Polar Research 2012, 31, 18367, http://dx.doi.org/10.3402/polar.v31i0.1836
Review of A complete guide to Antarctic wildlife: birds and mammals of the Antarctic Continent and the Southern Ocean, by Hadoram Shirihai
No full textThis impressive book is an invaluable, fully illustrated, wildlife guide for tourists and scientists visiting the Southern Ocean and Antarctica
The oldest elasmosaurs (Sauropterygia, Plesiosauria) from Antarctica, Santa Marta Formation (upper Coniacian? Santonian-upper Campanian) and Snow Hill Island Formation (upper Campanian-lower Maastrichtian), James Ross Island
No full textElasmosaurs are recorded for the first time in the Lachman Crags Member (Beta Member) of the Santa Marta Formation (lower Campanian) and in the Herbert Sound Member of the Snow Hill Island Formation (upper Campanian). These are the first elasmosaurids from James Ross Island, Antarctic Peninsula. These records greatly improve our knowledge of the taxonomic diversity of plesiosaurs of the Santa Marta Formation and Herbert Sound Member of the Snow Hill Island Formation, and extend the lower limit of the record of Elasmosauridae in Antarctica to the lower Campanian, making this the oldest record of an Antarctic elasmosaur.Keywords: Elasmosauridae; Antarctica; Late Cretaceous(Published: 30 October 2012)Citation: Polar Research 2012, 31, 11090, http://dx.doi.org/10.3402/polar.v31i0.1109
Eruption age of the Sverrefjellet volcano, Spitsbergen Island, Norway
No full textSverrefjellet is a Pleistocene-age basaltic volcanic construct on north-western Spitsbergen Island (Svalbard Archipelago, Norway). Published ages for the Sverrefjellet eruption range between 6000 years and ca. 1 million years before present. The age of the eruption is dated here as 1.05±0.07 (1s) My, consistent with Ar-Ar isochron and plateau ages of several analysed samples. Radiogenic Ar represents a small proportion of the released Ar, < 15% in nearly all samples. Non-radiogenic Ar components include air, excess 40Ar (seen as inverse isochron intercept values > 40Ar/36Ar=295.5), low-temperature alterations (Ar release at low temperature, with high Cl/K), carbonates and zeolites (Ar release at intermediate temperature) and xenolithic material (Ar release at high temperature, high Ca/K). The effects of the largely non-radiogenic argon sources is also seen in the total gas Ar-Ar “ages,” which range from 1.3 – 10.3 My, significantly larger than the inferred eruption age. It is likely that total gas Ar-Ar “ages” and whole-rock K-Ar “ages” of similar basalts also exceed their true eruption ages.Keywords: Svalbard; Spitsbergen; basalt; Knipovich; Ridge; Ar-Ar(Published: 2 March 2012)Citation: Polar Research 2012, 31, 17320, DOI: 10.3402/polar.v31i0.17320To access the supplementary material to this article please see Supplementary files in the column to the right (under Article Tools