Authors:Lucas Krüger; Vitor H. Paiva, Julia V.G. Finger, Elisa Petersen, José C. Xavier, Maria V. Petry, Jaime A. Ramos Pages: 271 - 277 Abstract: Literature reports that body size can be associated with latitudinal distribution, for instance larger animals inhabit higher latitudes and colder habitats. This rule can be applied for species and populations within a species. The potential influence of body size on non-breeding distribution and habitat use at the intra-population level was investigated for southern giant petrels Macronectes giganteus (Gmelin) from Elephant Island, South Shetland Islands. The non-breeding distribution of 23 individuals was tracked, and total body length, culmen length, wing length, wing load and body mass were measured. Positions of core areas were used to estimate the latitudinal distribution of each individual. Smaller individuals were found to be associated more with lower latitudes, where warmer conditions and more coastal and productive waters prevail, whereas large males were associated more with higher latitudes, with colder conditions near sea ice caps, presumably feeding on carrion or preying on penguins. This association reflects a latitudinal gradient, with smaller individuals positioning themselves towards the north, and larger individuals towards the south. In this case, body size, individual distribution and habitat use were found to be associated, highlighting the importance of studying potential effects of individual body size on the ecology of seabirds. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S0954102018000238 Issue No:Vol. 30, No. 5 (2018)
Authors:E.V. Pershina; E.A. Ivanova, E.V. Abakumov, E.E. Andronov Pages: 278 - 288 Abstract: The soil microbiome was investigated at environmentally distinct locations on King George Island in the South Shetland Islands (Antarctic Peninsula) using 16 S rRNA gene pyrosequencing. The taxonomic composition of the soil prokaryotes (bacteria and archaea) was evaluated at three sites representing human-disturbed soils (Bellingshausen Station) and soils undergoing different stages of deglaciation (fresh and old moraines located near Ecology Glacier). The taxonomic analysis revealed 20 bacterial and archaeal phyla, among which Proteobacteria (29.6%), Actinobacteria (25.3%), Bacteroidetes (15.8%), Cyanobacteria (11.2%), Acidobacteria (4.9%) and Verrucomicrobia (4.5%) comprised most of the microbiome. In a beta-diversity analysis, the samples formed separate clusters. The Bellingshausen Station samples were characterized by an increased amount of Nostoc sp. and Janibacter sp. Although the deglaciation history had less of an effect on the soil microbiome, the early stages of deglaciation (Sample 1) had a higher proportion of bacteria belonging to the families Xanthomonadaceae, Sphingomonadaceae and Nocardioidaceae, whereas the older moraines (Sample 2) were enriched with Chthoniobacteriacae and N1423WL. Solirubrobacteriales, Gaiellaceae and Chitinophagaceae bacteria were present in both stages of deglaciation, characterized by genus-level differences. Taxonomic analysis of the abundant operational taxonomic units (OTUs) revealed both endemic (Marisediminicola antarctica, Hymenobacter glaciei) and cosmopolitan bacterial species in the microbiomes. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S095410201800024X Issue No:Vol. 30, No. 5 (2018)
Authors:Mario La Mesa; Emilio Riginella, Fortunata Donato, Carlotta Mazzoldi Pages: 289 - 297 Abstract: The life history traits of bathydraconids, deep-living fishes distributed all around the Antarctic continent, are poorly known. In particular, very few data are available on the relatively rare genera Akarotaxis and Bathydraco. With the aim to fill this gap, sagittal otoliths and gonads were analysed to assess individual age and reproductive features of Akarotaxis nudiceps (Waite, 1916), Bathydraco macrolepis Boulenger 1907 and Bathydraco marri Norman, 1938 collected in the Weddell Sea. Based on the annual growth increment patterns, age estimates ranged between 6–11, 5–11 and 8–11 years for A. nudiceps, B. macrolepis and B. marri, respectively. Most of the gametogenetic processes could be described based on gonad histology for both sexes. Females shared the reproductive features commonly reported in notothenioids, such as group-synchronous ovary development and prolonged gametogenesis. Total fecundity estimates were comparable between the two species of Bathydraco (1500–2500 eggs/female), whereas that of Akarotaxis was one order of magnitude smaller (200–250 eggs/female). Consistently, the mean size of late vitellogenic oocytes showed an opposite trend, being 1.6–1.8 mm in Bathydraco and 2.2 mm in Akarotaxis. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S0954102018000317 Issue No:Vol. 30, No. 5 (2018)
Authors:Kevin A. Hughes; Marta Misiak, Yogabaanu Ulaganathan, Kevin K. Newsham Pages: 298 - 305 Abstract: The harsh climatic conditions and low levels of human activity in Antarctica, relative to other regions, means few non-native species have established. However, the risk of introductions is becoming greater as human activity increases. Non-native microorganisms can be imported to Antarctica in association with fresh food, cargo and personal clothing, but the likelihood of their establishment is not well understood. In January 2015, a wooden packing crate, heavily contaminated with fungi, was imported by aircraft from Punta Arenas, Chile, to Rothera Research Station, Antarctica. Mucor racemosus Bull. and two strains of Trichoderma viridescens (A.S. Horne & H.S. Will.) Jaklitsch & Samuels were isolated from the wood. Measurements of hyphal extension rates indicated that all three strains were psychrotolerant and capable of growth at 4°C, with M. racemosus growing at 0°C. The imported fungi could grow at rates equivalent to, or faster than, species isolated from Antarctic soils, suggesting that low temperature may not be a limiting factor for establishment. It is recommended that wood heat-treatment standards, equivalent to those described in the International Standards for Phytosanitary Measures No. 15, are employed by national operators importing cargo into Antarctica, and that treated wood is adequately stored to prevent fungal contamination prior to transportation. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S0954102018000329 Issue No:Vol. 30, No. 5 (2018)
Authors:Naresh C. Pant; Francisco J. Jimenez-Espejo, Cary P. Cook, Paromita Biswas, Robert Mckay, Claudio Marchesi, Motoo Ito, Dewashish Upadhyay, Junichiro Kuroda, Kenji Shimizu, Ryoko Senda, Tina Van De Flierdt, Yoshinori Takano, Katsuhiko Suzuki, Carlota Escutia, Prakash K. Shrivastava Pages: 307 - 321 Abstract: Unusual mafic rock fragments deposited in Plio-Pleistocene-aged marine sediments were recorded at Integrated Ocean Drilling Program (IODP) Site U1359, in Wilkes Land, East Antarctica. These fragments were identified from sediment layers deposited between c. 3 and 1.2 Ma, indicating a sustained supply during this time interval. Clinopyroxenes in these basalts are Al–Ti diopside–hedenbergite, uncommon in terrestrial magmatic rocks. A single strong peak in the Raman spectra of a phosphate-bearing mineral at 963 cm-1 supports the presence of merrillite. Although not conclusive, petrological traits and oxygen isotopic compositions also suggest that the fragments may be extra-terrestrial fragments affected by shock metamorphism. Nevertheless, it is concluded that the basaltic fragments incorporated in marine sediments at Site U1359 represent ice-rafted material supplied to the continental rise of East Antarctica, probably from the bedrocks near the proximal Ninnis Glacier. Further studies on Plio-Pleistocene sediments near Site U1359 are required to characterize the unusual mafic rocks described. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S0954102018000299 Issue No:Vol. 30, No. 5 (2018)
Authors:Sergi Gonzalez; Didac Fortuny Pages: 322 - 328 Abstract: The upward evolution of temperatures in the Antarctic Peninsula has weakened and even reversed in the last two decades. Due to the long-term variability in the region it is not easy to assess whether recent cooling trends are consistent with the internal variability or not. For this reason, this paper assesses the robustness of the trends by analysing their sensitivity with respect to the period selected. Every possible temperature trend in the interval 1958–2016 has been calculated and displayed in a two-dimensional parameter diagram. The results suggest that the warming observed in the Antarctic Peninsula since 1958 is quite robust, as all periods longer than 30 years exhibit statistically significant changes, especially in summer (with lower magnitude and higher significance) and autumn and winter (with larger magnitude and lower significance). Periods shorter than 30 years exhibit alternations of warming and cooling periods, and therefore do not represent robust trends even if they are statistically significant. Consequently, the recent 20-year cooling trend cannot be considered at the moment as evidence of a shift in the overall sign of the trend. PubDate: 2018-10-01T00:00:00.000Z DOI: 10.1017/S0954102018000251 Issue No:Vol. 30, No. 5 (2018)
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