Polar Research (E-Journal)
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Distribution of total alkalinity and pH in the Ross Sea (Antarctica) waters during austral summer 2008
No full textMeasurements of total alkalinity (AT) and pH were made in the Ross Sea in January–February 2008 in order to characterize the carbonate system in the Ross Sea and to evaluate the variability associated with different water masses. The main water masses of the Ross Sea, Antarctic Surface Water, High Salinity Shelf Water (HSSW), Deep Ice Shelf Water, Circumpolar Deep Water (CDW) and Antarctic Bottom Water, were identified on the basis of the physical and chemical data. In particular, the AT ranged between 2275 and 2374 µmol kg−1 with the lowest values in the surface waters (2275–2346 µmol kg−1), where the influence of the sea-ice melting and of the variability of the physical properties was significant. In the deep layers of the water column, the AT maxima were measured in correspondence to the preferential pathways of the spreading HSSW. The pH had variable values in the surface layer (7.890–8.033) with the highest values in Terra Nova Bay and Ross Sea polynyas. A low pH (7.969±0.025) traced the intrusion of the CDW in the Ross Sea shelf area. All samples revealed waters that were oversaturated with respect to both calcite and aragonite, but near corrosive levels of aragonite saturation state (Ω ca. 1.1–1.2) were associated with the entrainment of CDW over the slope. Aragonite undersaturation is of particular concern for the zooplankton species comprising to calcifying organisms such as pteropods. The partial pressure of CO2 at the sea surface was undersaturated with respect to the atmospheric value, particularly in Terra Nova Bay and the Ross Sea polynyas, but a large variability in the sea–air CO2 fluxes was observed associated with different responses in the strength of the biological and physical processes.Keywords: Total alkalinity; pH; saturation state; Terra Nova Bay polynya; Ross Sea(Published: 16 October 2014)Citation: Polar Research 2014, 33, 20403, http://dx.doi.org/10.3402/polar.v33.2040
Selected elements in surface waters of Antarctica and their relations with the natural environment
No full textThe aim of the study was to specify the concentration of selected chemical elements in surface waters of King George Island, off the western coast of the Antarctic Peninsula. The research encompassed six streams, a lake and an artificial water reservoir located on the western coast of Admiralty Bay. Measured hydrochemical parameters included pH, conductivity, total dissolved solids (TDS), and total and dissolved forms elements such as Al, Co, Ni, Cu, Zn, Cd, Pb, Mn, Fe, As and Se. The values of pH, conductivity and TDS had the following ranges: 6.09–8.21, 6.0–875 µS cm−1 and 7.0–975 mg/L, respectively, and were typical for surface waters of Antarctica. Wide disparities were discovered regarding concentrations of the investigated elements, ranging from <0.01 µg/L for Cd to 510 µg/L for Fe, and differing from one water body to another. The investigated elements are discussed with reference to environmental conditions and anthropogenic factors. Concentrations of total and dissolved forms of elements are considered in connection with the composition of soil in their surroundings and with atmospheric deposition, mostly such as that took place locally. The increased levels of Pb and Zn concentrations in the immediate proximity of a research station suggested anthropogenic contamination.Keywords: Antarctic surface waters; total and dissolved elements; baseline elements values; anthropogenic metal contamination(Published: 21 March 2014)To access the supplementary material for this article, please see Supplementary files in the column to the right (under Article Tools).Citation: Polar Research 2014, 33, 21417, http://dx.doi.org/10.3402/polar.v33.2141
Coastal glaciers advanced onto Jameson Land, East Greenland during the late glacial-early Holocene Milne Land Stade
No full textWe report on 10Be and optically stimulated luminescence ages from moraines and glaciolacustrine sediments on eastern Jameson Land, East Greenland. Sampled landforms and sediment are associated with advances of outlet glaciers from the local Liverpool Land ice cap situated in the coastal Scoresby Sund region. Previous studies have tentatively correlated these advances with the Milne Land Stade moraines, which are prominent moraine sets deposited by mountain glaciers in the inner Scoresby Sund region. Recent constraints on the formation of the outer and inner of these moraines have suggested two advances of local glaciers, one prior to or during the Younger Dryas and another during the Preboreal. In this paper, we test the correlation of the Liverpool Land glacial advance with the Milne Land Stade. Our results show that outlet glaciers from the Liverpool Land ice cap reached ice-marginal positions marked by moraines in east-facing valleys on Jameson Land sometime during late glacial–early Holocene time (ca. 13–11 Kya). This confirms the correlation of these moraines with the Milne Land Stade moraines described elsewhere in the Scoresby Sund region.Keywords: Greenland; Jameson Land; glaciation; Milne Land Stade; cosmogenic exposure dating; luminescence dating.(Published: 10 January 2014)Citation: Polar Research 2014, 33, 20313, http://dx.doi.org/10.3402/polar.v33.2031
Palaeoenvironment of Eocene prodelta in Spitsbergen recorded by the trace fossil Phycosiphon incertum
No full textIchnological, sedimentological and geochemical analyses were conducted on the Eocene Frysjaodden Formation in order to interpret palaeoenvironment prodelta sediments in the Central Basin of Spitsbergen. Phycosiphon incertum is the exclusive ichnotaxon showing differences in size, distribution, abundance and density, and relation to laminated/bioturbated intervals. Large P. incertum mainly occur dispersed, isolated and randomly distributed throughout the weakly laminated/non-laminated intervals. Small P. incertum occur occasionally in patches of several burrows within laminated intervals or as densely packed burrows in thin horizons in laminated intervals or constituting fully bioturbated intervals that are several centimetres thick. Ichnological changes are mainly controlled by oxygenation, although the availability of benthic food cannot be discarded. Changes in oxygenation and rate of sedimentation can be correlated with the registered variations in the Bouma sequence of the distal turbiditic beds within prodeltal shelf sediments.Keywords: Trace fossils; Phycosiphon; Eocene; prodelta; turbiditic sediments; Spitsbergen(Published: 20 October 2014)Citation: Polar Research 2014, 33, 23786, http://dx.doi.org/10.3402/polar.v33.2378
Environmental influences on the at-sea behaviour of a major consumer, Mirounga leonina, in a rapidly changing environment
No full textUnderstanding the distribution and foraging ecology of major consumers within pelagic systems, specifically in relation to physical parameters, can be important for the management of bentho-pelagic systems undergoing rapid change associated with global climate change and other anthropogenic disturbances such as fishing (i.e., the Antarctic Peninsula and Scotia Sea). We tracked 11 adult male southern elephant seals (Mirounga leonina), during their five-month post-moult foraging migrations from King George Island (Isla 25 de Mayo), northern Antarctic Peninsula, using tags capable of recording and transmitting behavioural data and in situ temperature and salinity data. Seals foraged mostly within the Weddell–Scotia Confluence, while a few foraged along the western Antarctic Peninsula shelf of the Bellingshausen Sea. Mixed model outputs suggest that the at-sea behaviour of seals was associated with a number of environmental parameters, especially seafloor depth, sea-ice concentrations and the temperature structure of the water column. Seals increased dive bottom times and travelled at slower speeds in shallower areas and areas with increased sea-ice concentrations. Changes in dive depth and durations, as well as relative amount of time spent during the bottom phases of dives, were observed in relation to differences in overall temperature gradient, likely as a response to vertical changes in prey distribution associated with temperature stratification in the water column. Our results illustrate the likely complex influences of bathymetry, hydrography and sea ice on the behaviour of male southern elephant seals in a changing environment and highlight the need for region-specific approaches to studying environmental influences on behaviour.Keywords: Southern elephant seals; foraging ecology; satellite-relay data loggers; King George Island; Isla 25 de Mayo; at-sea behaviourTo access the supplementary material for this article, please see the supplementary files in the column to the right (under Article Tools).(Published: 26 November 2014)Citation: Polar Research 2014, 33, 23808, http://dx.doi.org/10.3402/polar.v33.2380
At the root of the early penguin neck: a study of the only two cervicodorsal spines recovered from the Eocene of Antarctica
No full textThe spinal column of early Antarctic penguins is poorly known, mainly due to the scarcity of articulated vertebrae in the fossil record. One of the most interesting segments of this part of the skeleton is the transitional series located at the root of the neck. Here, two such cervicodorsal series, comprising reinterpreted known material and a new specimen from the Eocene of Seymour Island (Antarctic Peninsula), were investigated and contrasted with those of modern penguins and some fossil bones. The new specimen is smaller than the counterpart elements in recent king penguins, whereas the second series belonged to a large-bodied penguin from the genus Palaeeudyptes. It had been assigned by earlier researchers to P. gunnari (a species of “giant” penguins) and a Bayesian analysis—a Bayes factor approach based on size of an associated tarsometatarsus—strongly supported such an assignment. Morphological and functional studies revealed that mobility within the aforementioned segment probably did not differ substantially between extant and studied fossil penguins. There were, however, intriguing morphological differences between the smaller fossil specimen and the comparative material related to the condition of the lateral excavation in the first cervicodorsal vertebra and the extremely small size of the intervertebral foramen located just prior to the first “true” thoracic vertebra. The former feature could have resulted from discrepancy in severity of external pneumatization. Both fossils provided valuable insights into the morphology and functioning of the axial skeleton in early penguins.Keywords: Antarctic Peninsula; La Meseta Formation; Palaeogene; early Sphenisciformes; cervicodorsal vertebrae.(Published: 20 November 2014)Citation: Polar Research 2014, 33, 23861, http://dx.doi.org/10.3402/polar.v33.2386
Assessing the importance of human activities for the establishment of the invasive Poa annua in Antarctica
No full textBecause of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua. In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica, in order to unravel the effects of physical soil disturbance on the establishment and survival of P. annua. We found a positive correlation between abundance of P. annua and level of soil disturbance, and that survival of P. annua was 33% higher in sites with disturbed soil than non-disturbed. Finally, we found that disturbance conditions increased germination for P. annua, whereas for native species germination in experimentally disturbed soil was either unchanged or reduced compared to undisturbed soil. Our results indicate that human activities that modify abiotic soil characteristics could play an important role in the abundance of this invasive species. If the current patterns of human activities are maintained in Antarctica, the establishment success and spread of P. annua could increase, negatively affecting native flora.Keywords: Alien species; Colobanthus quitensis; Deschampsia antarctica; human disturbance; Poa annua; tourists.(Published: 23 June 2014)Citation: Polar Research 2014, 33, 21425, http://dx.doi.org/10.3402/polar.v33.2142
Demographic population structure and fungal associations of plants colonizing High Arctic glacier forelands, Petuniabukta, Svalbard
No full textThe development of vegetation in Arctic glacier forelands has been described as unidirectional, non-replacement succession characterized by the gradual establishment of species typical for mature tundra with no species turnover. Our study focused on two early colonizers of High Arctic glacier forelands: Saxifraga oppositifolia (Saxifragaceae) and Braya purpurascens (Brassicaceae). While the first species is a common generalist also found in mature old growth tundra communities, the second specializes on disturbed substrate. The demographic population structures of the two study species were investigated along four glacier forelands in Petuniabukta, north Billefjorden, in central Spitsbergen, Svalbard. Young plants of both species occurred exclusively on young substrate, implying that soil conditions are favourable for establishment only before soil crusts develop. We show that while S. oppositifolia persists from pioneer successional stages and is characterized by increased size and flowering, B. purpurascens specializes on disturbed young substrate and does not follow the typical unidirectional, non-replacement succession pattern. Plants at two of the forelands were examined for the presence of root-associated fungi. Fungal genus Olpidium (Fungus incertae sedis) was found along a whole successional gradient in one of the forelands.Keywords: Colonizer; deglaciation; endophyte; High Arctic; Olpidium; succession.(Published: 30 April 2014)Citation: Polar Research 2014, 33, 20797, http://dx.doi.org/10.3402/polar.v33.2079
Long-term temperature trends and variability on Spitsbergen: the extended Svalbard Airport temperature series, 1898-2012
No full textOne of the few long instrumental records available for the Arctic is the Svalbard Airport composite series that hitherto began in 1911, with observations made on Spitsbergen, the largest island in the Svalbard Archipelago. This record has now been extended to 1898 with the inclusion of observations made by hunting and scientific expeditions. Temperature has been observed almost continuously in Svalbard since 1898, although at different sites. It has therefore been possible to create one composite series for Svalbard Airport covering the period 1898–2012, and this valuable new record is presented here. The series reveals large temperature variability on Spitsbergen, with the early 20th century warming as one striking feature: an abrupt change from the cold 1910s to the local maxima of the 1930s and 1950s. With the inclusion of the new data it is possible to show that the 1910s were colder than the years at the start of the series. From the 1960s, temperatures have increased, so the present temperature level is significantly higher than at any earlier period in the instrumental history. For the entire period, and for all seasons, there are positive, statistically significant trends. Regarding the annual mean, the total trend is 2.6°C/century, whereas the largest trend is in spring, at 3.9°C/century. In Europe, it is the Svalbard Archipelago that has experienced the greatest temperature increase during the latest three decades. The composite series may be downloaded from the home page of the Norwegian Meteorological Institute and should be used with reference to the present article.Keywords: Arctic; homogenization; Spitsbergen; Svalbard; temperature records; temperature trends.(Published: 22 January 2014)To access the supplementary material for this article, please see Supplementary files in the column to the right (under Article Tools).Citation: Polar Research 2014, 33, 21349, http://dx.doi.org/10.3402/polar.v33.2134
Review of The fast-changing Arctic: rethinking security for a warmer world, edited by Barry Scott Zellen
No full textHow will the changes currently taking place in the Arctic affect the future nature of interstate relations in the region? To what extent, and how, will the decline in summer and winter sea ice in the Polar Basin lead to changes in the pattern of human activity in the Arctic? How do the Arctic states approach the region and each other, and to what extent are their Arctic strategies compatible? Will the Arctic become an arena of jurisdictional disputes and heightened military tension, or will it become a region of cooperation and prosperity? These are among the core questions addressed in The fast-changing Arctic: rethinking security for a warmer world, edited by Barry Scott Zellen.
(Published: 19 February 2014)
Citation: Polar Research 2014, 33, 23951, http://dx.doi.org/10.3402/polar.v33.23951