Polar Research (E-Journal)
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Phosphate solubilizing ability of two Arctic Aspergillus niger strains
No full textMany filamentous fungi were isolated from the soils of Ny-Ålesund, Spitsbergen, Svalbard, and were screened in vitro for their phosphate solubilizing ability. Two strains of Aspergillus niger showed good tricalcium phosphate (TCP) solubilizing ability in Pikovskaya’s medium. The TCP solubilization index was calculated at varying levels of pH and temperatures. The ability of Aspergillus niger strain-1 to solubilize and release inorganic-P was 285µg ml-1, while Aspergillus niger strain-2 solubilized 262 µg ml-1 from 0.5% TCP after 7 days. This is the first report of TCP solubilization by Arctic strains that may serve as very good phosphate solubilizers in the form of biofertilizer.Kewords: Phosphate, Arctic, fungi, Aspergillus(Published: 15 June 2011)Citation: Polar Research 2011, 30, 7283, DOI: 10.3402/polar.v30i0.728
The oldest plesiosaur (Reptilia, Sauropterygia) from Antarctica
No full textAntarctic plesiosaurs are known from the Upper Cretaceous López de Bertodano and Snow Hill Island formations (Campanian to upper Maastrichtian), which crop out within the James Ross Basin region of the Antarctic Peninsula. Here we describe the first plesiosaur fossils from the Lachman Crags Member of the Santa Marta Formation, north-western James Ross Island. This material constitutes the stratigraphically oldest plesiosaur occurrence presently known from Antarctica, extending the occurrence of plesiosaurians in this continent back to Santonian times (86.3-83.5 Mya). Furthermore, MN 7163-V represents the first plesiosaur from this region not referable to the Elasmosauridae nor Aristonectes, indicating a greater diversity of this group of aquatic reptiles in Antarctica than previously suspected.Keywords: James Ross Island; Antarctica; plesiosauria; Late Cretaceous; Museu Nacional; oldest(Published: 7 June 2011)Citation: Polar Research 2011, 30, 7265, DOI: 10.3402/polar.v30i0.726
Colonization and demographic structure of Deschampsia antarctica and Colobanthus quitensis along an altitudinal gradient on Livingston Island, South Shetland Islands, Antarctica
No full textThe colonization capacity and demographic structure of populations of Deschampsia antarctica and Colobanthus quitensis were studied in different microhabitats between 10 and 147 m a.s.l. on Livingston Island, South Shetland Islands, near the Spanish Antarctic base Juan Carlos I, in February 2002. At the highest site (147 m a.s.l.), mean temperatures were about 1 ºC lower than at sea level. Both species are less common in inland areas and at the highest altitudes only occur at restricted sites that are frequently snow-free in the early austral summer. The diameters of the largest plants (C. quitensis cushions 7-8 cm ; D. antarctica tufts 10-11 cm) in the populations growing at the highest altitudes (110 and 147 m a.s.l.) suggest that these populations were established about 24-28 years ago. The largest diameter plants (Deschampsia 20 cm; Colobanthus 18 cm) were found at the lowest altitudes on deep soil. The presence of numerous seedlings and young individuals on the periphery of populations established several years ago or at recently colonized sites suggests an active process of expansion. There were more emerged seedlings of C. quitensis than of D. antarctica, but the density of established individuals was higher for D. antarctica, suggesting these species have different demographic strategies.Keywords: Antarctic vascular plants; altitude and habitat effect; colonization; population structure(Published: 13 May 2011)Citation: Polar Research 2011, 30, 7146, DOI: 10.3402/polar.v30i0.714
Warm Arctic - cold continents: climate impacts of the newly open Arctic Sea
No full textRecent Arctic changes are likely due to coupled Arctic amplification mechanisms with increased linkage between Arctic climate and sub-Arctic weather. Historically, sea ice grew rapidly in autumn, a strong negative radiative feedback. But increased sea-ice mobility, loss of multi-year sea ice, enhanced heat storage in newly sea ice-free ocean areas, and modified wind fields form connected positive feedback processes. One-way shifts in the Arctic system are sensitive to the combination of episodic intrinsic atmospheric and ocean variability and persistent increasing greenhouse gases. Winter 2009/10 and December 2010 showed a unique connectivity between the Arctic and more southern weather patterns when the typical polar vortex was replaced by high geopotential heights over the central Arctic and low heights over mid-latitudes that resulted in record snow and low temperatures, a warm Arctic - cold continents pattern. The negative value of the winter (DJF 2009/10) North Atlantic Oscillation (NAO) index associated with enhanced meridional winds was the lowest observed value since the beginning of the record in 1865. Wind patterns in December 2007 and 2008 also show an impact of warmer Arctic temperatures. A tendency for higher geopotential heights over the Arctic and enhanced meridional winds are physically consistent with continued loss of sea ice over the next 40 years. A major challenge is to understand the interaction of Arctic changes with climate patterns such as the NAO, Pacific North American and El Niño-Southern Oscillation.
Keywords: Climate change; sea ice; atmospheric circulation; North Atlantic Oscillation
(Published: 29 December 2011)
Citation: Polar Research 2011, 30, 15787, DOI: 10.3402/polar.v30i0.1578
Review of Negotiating the Arctic:The Construction of an International Region, by E. C. H. Keskitalo
No full textSince the waning of the cold war during the late 1980s, the Arctic has emerged as a lively arena for initiatives designed to promote international cooperation. These initiatives take a variety of forms. Some, like the Arctic Environmental Protection Strategy (AEPS) and its successor the Arctic Council (AC), involve intergovernmental agreements. Others, such as the Northern Forum (NF), are collaborative efforts on the part of subnational units of government (e.g. counties, provinces, states). Still others, like the International Arctic Science Committee (IASC), the University of the Arctic (UArctic), and the Inuit Circumpolar Conference (ICC), feature efforts on the part of nongovernmental bodies to infl uence the course of transnational relations
Palynodebris analysis of a shallow core from the Barents Sea
No full textA quantitative study of palynomorphs and palynodebris in a shallow core from the central part of Bjbrn0yrenna. western Barents Sea, is presented. The core could be subdivided into a lower part characterized by a complete dominance of reworked plant debris of Mesozoic age and an upper part with considerable input of first cycle algal debris and dinoflagellate cysts. Two hypotheses are suggested to explain this radical change in palynodebris composition. Either it represents a transition from a situation with permanent ice to normal marine conditions, or the absence of first cycle plant debris in the lower part of the core is caused by a masking of this component due to extremely high input of glacially eroded material from the bordering shallow parts of the Barents Sea. The present study shows that palynodebris analysis may contribute important information to the study of composition and depositional environment of Quaternary marine sediments in the area
Observations on the wader populations at Ny-Alesund, Spitsbergen, 1982
No full textDuring the summer of 1982 waders, Charadriidae, were recorded regularly by FM in the station area of Ny-Alesund (78"55'N, ll"56'E). From 6 to 18 July waders were censused by HM and JF in a 6.32 kmz area around Ny-Alesund (Fig. 1). Parts of the area were covered each day and all birds seen were mapped. All suitable habitats were covered within a distance of 25-50111 at least once, and early snow-free ridges were surveyed especially
Modelling the dynamics of snow cover, soil frost and surface ice in Norwegian grasslands
No full textStudying the winter survival of forage grasses under a changing climate requires models that can simulate the dynamics of soil conditions at low temperatures. We developed a simple model that simulates depth of snow cover, the lower frost boundary of the soil and the freezing of surface puddles. We calibrated the model against independent data from four locations in Norway, capturing climatic variation from south to north (Arctic) and from coastal to inland areas. We parameterized the model by means of Bayesian calibration, and identified the least important model parameters using the sensitivity analysis method of Morris. Verification of the model suggests that the results are reasonable. Because of the simple model structure, some overestimation occurs in snow and frost depth. Both the calibration and the sensitivity analysis suggested that the snow cover module could be simplified with respect to snowmelt and liquid water content. The soil frost module should be kept unchanged, whereas the surface ice module should be changed when more detailed topographical data become available, such as better estimates of the fraction of the land area where puddles may form
Review of Climate change: the science, impacts and solutions, by A. Barrie Pittock
No full textIt is almost the resort of rascals to claim at the beginning of a book review that “the subject of this book has never been more topical and its publication could not be more timely”. Nonetheless, neither Barrie Pittock nor I are rascals, and the above statement is true. In fact, as I write this review, the Australian Senate, which has been held back from its Christmas recess to complete its debate on a bill to initiate greenhouse gas emissions reduction, is arguing about the cause and its possible cure. I wish I could have every member of the Senate (especially the dissenters in the Liberal Party) read the 350 pages of Barrie’s excellent book. Of course, as with all good books, they could simply read Chapter 1 “Climate change matters” and Chapter 12 “Accepting the challenge”, but as these rascals are politicians it might also be useful for them to read Chapter 10, entitled “The politics of greenhouse”
Arctic cephalopod distributions and their associated predators
No full textCephalopods are key species of the eastern Arctic marine food web, both as prey and predator. Their presence in the diets of Arctic fish, birds and mammals illustrates their trophic importance. There has been considerable research on cephalopods (primarily Gonatus fabricii) from the north Atlantic and the west side of Greenland, where they are considered a potential fishery and are taken as a by-catch. By contrast, data on the biogeography of Arctic cephalopods are still incomplete. This study integrates most known locations of Arctic cephalopods in an attempt to locate potential areas of interest for cephalopods, and the predators that feed on them. International and national databases, museum collections, government reports, published articles and personal communications were used to develop distribution maps. Species common to the Canadian Arctic include: G. fabricii, Rossia moelleri, R. palpebrosa and Bathypolypus arcticus. Cirroteuthis muelleri is abundant in the waters off Alaska, Davis Strait and Baffin Bay. Although distribution data are still incomplete, groupings of cephalopods were found in some areas that may be correlated with oceanographic variables. Understanding species distributions and their interactions within the ecosystem is important to the study of a warming Arctic Ocean and the selection of marine protected areas