Palaeogene volcanics with plant-bearing sediment intercalations crop out extensively on King George Island in the South Shetland Islands, West Antarctica. The plant fossil assemblages are the most complete Palaeogene terrestrial foliar record in Antarctica. Compositional variations in the flora have previously been used to construct climate change models for the Tertiary. King George Island is part of the late Triassic to Recent, Andean - West Antarctic subducting margin. Eastwards subduction oceanic crust beneath the Antarctic Peninsula resulted in mountain building and crustal melting at depth that in turn led to large stratovolcanoes and active pyroclastic volcanism (Leat et al., 1995). Consequently the flora is preserved in a range of primary and reworked volcaniclastic sediments, that were deposited in lacustrine and ephemeral lacustrine basins developed on the volcanic surface. The King George Island flora consists of impressions and carbonised compressions of leaves of angiosperms, ...
The Notothenioidei dominates the fish fauna of the Antarctic in both biomass and diversity. This clade exhibits adaptations related to metabolic function and freezing avoidance in the subzero Antarctic waters, and is characterized by a high degree of morphological and ecological diversity. Investigating the macroevolutionary processes that may have contributed to the radiation of notothenioid fishes requires a well-resolved phylogenetic hypothesis. To date published molecular and morphological hypotheses of notothenioids are largely congruent, however, there are some areas of significant disagreement regarding higher-level relationships. Also, there are critical areas of the notothenioid phylogeny that are unresolved in both molecular and morphological phylogenetic analyses. Previous molecular phylogenetic analyses of notothenioids using partial mtDNA 12S and 16S rRNA sequence data have resulted in limited phylogenetic resolution and relatively low node support. One particularly controversial result
This study was conducted to describe the cardiovascular responses to intra-arterial injections of serotonin in the Antarctic fish Pagothenia borchgrevinki and to elucidate the underlying mechanisms. Immunohistochemistry was used to localise serotonin-containing cells within the gills. Simultaneous and continuous recordings of ventral and dorsal aortic blood pressure, heart rate and ventral aortic blood flow (cardiac output) were made using standard cannulation procedures in combination with Doppler flow measurement. An extracorporeal loop with an in-line oxygen electrode allowed continuous measurements of arterial oxygen pressure PaO2. Pre-branchial injection of serotonin (5-hydroxytryptamine, 5-HT) or the 5-HT2 receptor agonist alpha-methylserotonin increased the branchial vascular resistance and ventral aortic pressure, while the 5-HT1 receptor agonist piperazine was without effect. The branchial vasoconstriction produced by serotonin injection was completely blocked by the 5-HT1/5-HT2 ...
The ocellated icefish (Chionodraco rastrospinosus) is a fish of the family Channichthyidae. It lives in the cold waters off Antarctica and is known for having transparent haemoglobin-free blood. C. rastrospinosus live in the Southern Ocean up to a depth of 1 km. They grow up to 52 centimetres (20 in) and average 30 centimetres (12 in). The adults feed on krill and other fish. Larvae are 17 mm long when they hatch, and grow by about 2 mm a week. The larval stage lasts for up to 18 months during which they feed mainly on krill. They become sexually mature at four years, and normally live up to about eight years, but sometimes as long as twelve. In the Antarctic autumn, adult C. rastrospinosus migrate to shallow waters to spawn at a depth of 200-300 m. The eggs are scattered and hatch six months later around April. Haemoglobin gives oxygenated blood its red colour. Unlike other vertebrates, fish of the Antarctic icefish family (Channichthyidae) do not use haemoglobin to transport oxygen around ...
The Antarctic icefishes (family Channichthyidae, suborder Notothenioidei) constitute the only vertebrate taxon that fails to produce red blood cells. These fishes can be paired with closely related, but erythrocyte-producing, notothenioids to discover erythropoietic genes via representational difference analysis. Using a B30.2-domain-encoding DNA probe so derived from the hematopoietic kidney (pronephros) of a red-blooded Antarctic rockcod, Notothenia coriiceps, we discovered a related, novel gene, bloodthirsty (bty), that encoded a 547-residue protein that contains sequential RING finger, B Box, coiled-coil, and B30.2 domains. bty mRNA was expressed by the pronephric kidney of N. coriiceps at a steady-state level 10-fold greater than that found in the kidney of the icefish Chaenocephalus aceratus. To test the function of bty, we cloned the orthologous zebrafish gene from a kidney cDNA library. Whole-mount in situ hybridization of zebrafish embryos showed that bty mRNA was present throughout ...
The purpose of this study was to extend our investigation into the regulation of the HSR in the Antarctic notothenioid fish Trematomus bernacchii, a species that appears to lack heat-inducible Hsp expression (Hofmann et al., 2000). The fishes endemic to the Southern Ocean display a range of biochemical and molecular processes that allow them to tolerate their extreme environment and, in some cases, have lost attributes common to other fish (Somero et al., 1998). These changes include the production of anti-freeze proteins (DeVries, 1988), the loss of hemoglobin and/or myoglobin in some species (Cocca et al., 1997; Sidell et al., 1997; Somero et al., 1998) and the storage of extra lipid reserves for energy (Sidell et al., 1995), buoyancy (Eastman, 1988) and for aiding in oxygen delivery to tissues (Londraville and Sidell, 1990). To address the possibility that such a cold-adapted species could lose an otherwise highly conserved cellular response to heat stress, we examined the expression of hsp ...
Hoffman, J., Peck, L., Linse, K., & Clarke, A. C. (2011). Strong population genetic structure in a broadcast-spawning Antarctic marine invertebrate. Journal of Heredity, 102(1), 55-66. doi:10.1093/jhered/ ...
The Antarctic marine fauna has been isolated in the cold (-2°C), stable, and oxygen-rich Southern Ocean for 25 million years, and consequently these animals are extremely cold-adapted. One family within the Antarctic notothenioid fishes, the icefish, has lost the capacity to produce erythrocytes and the oxygen transport protein hemoglobin. Their profound anemia makes them an evolutionary mutant model of human anemias. Using a comparative-genomic approach, we have isolated 10 novel genes that are differentially expressed by the red-blooded species Notothenia coriiceps and the "white-blooded" icefish, Chaenocephalus aceratus, and may be novel genes involved in erythropoiesis. We have identified one of these genes (hemogen - hemgn) as a putative ortholog of mammalian EDAG and RP59. In mammals, these genes are involved in the proliferation of blood and bone cells, however, whether the putative ortholog hemgn functions similarly in fishes has not be reported. In the current study, we use a ...
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The major ions, sodium (Na+), calcium (Ca2+), and chloride (Cl−), deposited in central Antarctica and preserved in ice cores originate from both marine and continental sources. They provide important proxy records, helping to reconstruct past climatic processes. However, it is difficult to clearly separate the individual contributions from the two sources, particularly the continental one during glacial periods. On the basis of Na+ and Ca2+ records at an unprecedented resolution from the European Project for Ice Coring in Antarctica (EPICA) Dome C ice core back to the penultimate glacial period, mean ion mass ratios were deduced for the continental and the sea-salt aerosol body over East Antarctica. The sea-salt ion mass ratios are in the range predicted for both wind-induced bubble bursting of breaking waves on the open ocean and sea ice brine-derived aerosols, respectively, thus allowing no clear decision on the contribution of sea ice to the central Antarctic sea-salt aerosol. The ...
The Census of Antarctic Marine Life (CAML) and its polar counterpart, Arctic Ocean Diversity, have pioneered new understandings of the evolution and diversity of life.. Led by the Australian Antarctic Division, CAML coordinated 18 major research voyages to Antarctica and the Southern Ocean during the IPY. Australian scientists participated in three CAML voyages focusing on waters adjacent to East Antarctica - known as the Collaborative East Antarctic Marine Census (CEAMARC). These voyages, aboard Japans Umitaka Maru, Frances LAstrolabe and Australias Aurora Australis, studied sea-bed communities and the deep pelagic (open ocean) zone of the region adjacent to Terre Adélie and George V Land.. Altogether, CAML revealed that Antarctica is a single bioregion united by the Circumpolar Current - the largest current in the world. Previously thought to be low in species diversity, the Antarctic is now known to have an unexpected richness of life. In addition, molecular techniques show Antarctica to ...
The Antarctic Ecosystem Research Division ( AERD) conducts research to fulfill NOAAs mandate of providing scientific advice that supports United States (U.S.) interests related to resource management by the Commission for the Conservation of Antarctic Marine Living Resources ( CCAMLR), of which the U.S. is a Member. NOAA Fisheries Antarctic research is mandated by the U.S. Antarctic Marine Living Resources (AMLR) Convention Act of 1984, thus the program of work undertaken and managed by the AERD is widely known as the U.S. AMLR Program. The U.S. AMLR Program is internationally recognized for its ongoing contributions to ecosystem-based management of fisheries that impact krill, finfishes, krill-dependent predators, and other components of the Antarctic ecosystem. The AERD manages the US AMLR Program under the direction of George Watters. ...
The Antarctic Ecosystem Research Division ( AERD) conducts research to fulfill NOAAs mandate of providing scientific advice that supports United States (U.S.) interests related to resource management by the Commission for the Conservation of Antarctic Marine Living Resources ( CCAMLR), of which the U.S. is a Member. NOAA Fisheries Antarctic research is mandated by the U.S. Antarctic Marine Living Resources (AMLR) Convention Act of 1984, thus the program of work undertaken and managed by the AERD is widely known as the U.S. AMLR Program. The U.S. AMLR Program is internationally recognized for its ongoing contributions to ecosystem-based management of fisheries that impact krill, finfishes, krill-dependent predators, and other components of the Antarctic ecosystem. The AERD manages the US AMLR Program under the direction of George Watters. ...
We review the scientific literature, especially from the past decade, on the impacts of human activities on the Antarctic environment. A range of impacts has been identified at a variety of spatial and temporal scales. Chemical contamination and sewage disposal on the continent have been found to be long-lived. Contemporary sewage management practices at many coastal stations are insufficient to prevent local contamination but no introduction of non-indigenous organisms through this route has yet been demonstrated. Human activities, particularly construction and transport, have led to disturbances of flora and fauna. A small number of non-indigenous plant and animal species has become established, mostly on the northern Antarctic Peninsula and southern archipelagos of the Scotia Arc. There is little indication of recovery of overexploited fish stocks, and ramifications of fishing activity on bycatch species and the ecosystem could also be far-reaching. The Antarctic Treaty System and its ...
Antarctic sea ice is constantly on the move as powerful winds blow it away from the coast and out toward the open ocean. A new study shows how that ice migration may be more important for the global ocean circulation than anyone realized.
Lemke, P. (1980): Linear stochastic dynamic model of Arctic and Antarctic sea ice variability , Workshop on Stochastic Dynamic Forecasting, October 1979, ECMWF, Reading, England ...
Plankton sampling by the training vessel Umitaka-maru in the Indian sector of the Southern Ocean in the austral summer of 2010/2011Plankton sampling by the training vessel Umitaka-maru in the Indian sector of the Southern Ocean in the austral summer of 2010/2011AA12026903 ...
April Flowers for redOrbit.com - Your Universe Online One of the fastest warming regions on the planet - and the fastest warming part of the Southern Hemisphere - is the western Antarctic Peninsula. This warming has been the subject of scientific debate, especially in light of recent instrumental records of both atmospheric and oceanic warming from the region. Holding an equivalent of 5 meters of global sea level rise locked in ice, the Antarctic ice sheet is becoming increasingly vulnerable to collapse as the atmosphere and oceans continue to warm.. A new study from Cardiff University, published in a recent issue of Nature Geoscience, has traced glacial ice entering the ocean along the western Antarctic Peninsula using a unique 12,000-year record of microscopic marine algae fossils. The findings reveal that in the late Holocene - approximately 3500 - 250 years ago - the atmosphere had a more significant impact on warming along the western Antarctic Peninsula than oceanic circulation did.. Prior ...
Roberts, Donna (1997) Reconstruction of lake-water salinity from fossil diatom assemblages in saline lakes of the Vestfold Hills, Antarctica. PhD thesis, University of Tasmania. ...
Half of all vertebrate species share a series of chromosome fusions that preceded the teleost genome duplication (TGD), but we do not understand the causative evolutionary mechanisms. The Robertsonian-translocation hypothesis suggests a regular fusion of each ancestral acro- or telocentric chromosome to just one other by centromere fusions, thus halving the karyotype. An alternative genome-stirring hypothesis posits haphazard and repeated fusions, inversions, and reciprocal and nonreciprocal translocations. To study large-scale karyotype reduction, we investigated the decrease of chromosome numbers in Antarctic notothenioid fish. Most notothenioids have 24 haploid chromosomes, but bullhead notothen (Notothenia coriiceps) has 1. To understand mechanisms, we made a RAD-tag meiotic map with approximate to 10,000 polymorphic markers. Comparative genomics aligned about a thousand orthologs of platyfish and stickleback genes along bullhead chromosomes. Results revealed that 9 of 11 bullhead chromosomes arose
Early ecological research in McMurdo Sound revealed local spatial gradients in community structure associated with variations in anchor ice disturbance, fast ice and snow cover, and the effects of predators. Research contrasting the east and west sides of McMurdo Sound has shown major differences in benthic communities, which have been attributed to oceanographic influences on the advection of water-column productivity and the frequency of fast ice break-out. Despite these regional and local differences, coastal benthic communities in McMurdo Sound show a high level of stability, and contain a variety of large and potentially very long-lived species. In Terra Nova Bay, about half way along the Victoria Land Coast of the western Ross Sea, the coastal benthic communities provide some insightful contrasts with those in McMurdo Sound. For example, the abundance and depth distribution of dominant species such as Sterechinus neumayeri and Adamussium colbecki are markedly different from McMurdo Sound. ...
The waters around South Georgia are among the most productive in the Southern Ocean, with zooplankton populations close to the island, in particular Antarctic krill, supporting vast colonies of higher predators. However, our understanding of the processes governing variability in the supply of these food resources is limited by the poor spatial and temporal resolution of available data. Here, we use a numerical modeling approach to examine the underlying physical processes driving the recruitment and retention of zooplankton to the South Georgia shelf. Variability in the magnitude and spatial distribution of recruitment was dominated by the proximity and orientation of the southern Antarctic Circumpolar Current front to the shelf edge. Shelf retention was highest for source sites on the southwest shelf, with the main transport routes off the shelf to the north and northwest. Retention was lowest in the austral summer and winter; in summer increased glacial melt drives stronger off-shelf ...
The microbial communities that inhabit lithic niches inside sandstone in the Antarctic McMurdo Dry Valleys of life’s limits on Earth. The cryptoendolithic communities survive in these ice-free areas that have the lowest temperatures on Earth coupled with strong thermal fluctuations, extreme aridity, oligotrophy and high levels of solar and UV radiation. In this study, based on DNA metabarcoding, targeting the fungal Internal Transcribed Spacer region 1 (ITS1) and multivariate statistical analyses, we supply the first comprehensive overview onto the fungal diversity and composition of these communities sampled over a broad geographic area of the Antarctic hyper-arid cold desert. Six locations with surfaces that experience variable sun exposure were sampled to compare communities from a common area across a gradient of environmental pressure. The Operational Taxonomic Units (OTUs) identified were primarily members of the Ascomycota phylum, comprised mostly of the Lecanoromycetes and Dothideomycetes
Thehemolysateofthe AntarcticteleostGobionotothen gibberifrons(family Nototheniidae) contains two hemoglo-bins (Hb 1 andHb 2). The concentration of Hb 2 (15-20% of the total hemoglobin content) is higher than that found in most cold-adapted Notothenioidei. Unlike the other Antarctic species so far examined having two hemoglobins, Hb 1 and Hb 2 do not have globin chains in common. Therefore this hemoglobin system is made of four globins (two a-and twob-chains). The complete amino-acid sequence of the two hemoglobins (Hb 1,a 1 2b 1 2 ;Hb 2,a 2 b 2 2 ) has been established. ... ...
As expected, the population and allele patterns found within the Kerguelen Archipelago allow some general conclusions on the fate of populations after initial colonization. First of all, we note that these mice have retained a certain amount of genetic diversity. The heterozygosity values, as well as the average number of alleles, are comparable to the sample that we caught within a single deme in Europe (Paris). Since the mice that came with the first ship would likely represent the deme from the harbor where the ship started, we can assume that the mice entering these ships had a similarly reduced diversity (when compared to the diversity across demes in the French and German populations). Hence, there may have been only little additional loss of genetic diversity during the ship passage and after colonization. In population genetic terms this means that the mouse population would have quickly expanded after arrival on the Kerguelen Archipelago, which would have prevented further loss of ...
In a study spanning two decades, a team of researchers led by Colorado State University found declining numbers of soil fauna, nematodes and other animal species in the McMurdo Dry Valleys, one of the worlds driest and coldest ...
THE KERGUELEN ISLANDS are the exposed part of the Kerguelen oceanic plateau, a Large Igneous Province in the Antarctic plate domain. Its birth is related to both the spreading of the South East Indian Ridge (SEIR) overprinted by the long-lived Kerguelen plume. It provides a unique opportunity to study plume-ridge interactions and their implications for the composition of the oceanic mantle. Mantle xenoliths from the Kerguelen Islands are common in dykes or pipes of young alkaline lavas. The major and lithophile trace elements have been well-characterised over the last decade. The platinum group elements (PGE; Os, Ir, Ru, Rh, Pd, Pt) and chalcophile elements (S, Se, Cu) provide different information on the geological processes that operate in the lithosphere. This is because they are almost exclusively partitioned into a sulfide-rich melt, whereas major and lithophile trace elements have a greater affinity for silicate melts.. The PGE, S, Se and Cu were analysed in representative mantle xenoliths ...
ePIC (electronic Publication Information Center) is the official repository for publications and presentations of Alfred Wegener Institute for Polar and Marine Research (AWI)
Chen, Z.Z., Cheng ,C.H.C., Zhang, J.F., Cao, L.X., Chen, L., Zhou, L.H., Jin, Y.D., Ye, H., Deng, C., Dai, Z.H., Xu, Q.H., Hu, P., Sun, S.H., Shen, Y. and Chen, L.B.(2008) Transcrintomic and genomic evolution under constant cold in Antarctic notothenioid fish. Proceedings of the National Academy of Sciences of the United States of America 105:12944-12949. The sub-zero temperatures of the Southern Oceans require special adaptation to these extreme conditions, and the unique fish fauna of this region has provided textbook examples of molecular adaptation and molecular evolution in the context of thermal physiology. Previous studies have typically investigated single loci, but, in an exciting new survey, Chen et al. (2008) take a novel approach to characterize the genome-wide changes in gene transcription and relate these to adaptation to the cold Antarctic waters. A particular strength of this research is its tripartite strategy ...
A long-term soil manipulation experiment has been conducted as part of the McMurdo Dry Valleys Long Term Ecological Research (LTER) project. This table contains hourly soil temperature measurements associated with the long-term manipulation experiment on the south side of Lake Hoare, Taylor Valley, Antarctica ...
A long-term soil manipulation experiment has been conducted as part of the McMurdo Dry Valleys Long Term Ecological Research (LTER) project. This table contains hourly soil temperature measurements associated with the long-term manipulation experiment on the south side of Lake Hoare, Taylor Valley, Antarctica ...
Background Sooty (Puffinus griseus) and short-tailed (P. tenuirostris) shearwaters are abundant seabirds that range widely across global oceans. Understanding the foraging ecology of these species in the Southern Ocean is important for monitoring and ecosystem conservation and management. Methodology/Principal Findings Tracking data from sooty and short-tailed shearwaters from three regions of New Zealand and Australia were combined with at-sea observations of shearwaters in the Southern Ocean, physical oceanography, near-surface copepod distributions, pelagic trawl data, and synoptic near-surface winds. Shearwaters from all three regions foraged in the Polar Front zone, and showed particular overlap in the region around 140°E. Short-tailed shearwaters from South Australia also foraged in Antarctic waters south of the Polar Front. The spatial distribution of shearwater foraging effort in the Polar Front zone was matched by patterns in large-scale upwelling, primary production, and abundances of
In Antarctica, the environmental conditions and the restrictions imposed by the Antarctic Treaty prevent inoculation with foreign bacteria. Therefore, our aim was to investigate native bacterial consortia which might serve to design bacterial formulas suitable for soil bioremediation processes at cold temperatures. Two bacterial consortia, M10 and J13, were isolated from diesel contaminated Antarctic soils. Their ability to use hydrocarbons was evaluated in vitro and by the detection of three catabolic genes (alkB, nahAc, xylE). Both consortia showed similar 16S rRNA gene profiles, suggesting the presence of the same phylotypes. Total 16S rDNA was cloned from M10 grown on diesel. Sixty clones were screened, grouped by restriction profiles of PCR-amplified inserts and sequenced. T-RFLP (Terminal-Restriction-Fragment-Length-Polymorphism) of clones showed that all phylotypes from the entire consortia were recovered. A culture-dependent approach was used to isolate M10 components able to utilise ...
Sampling campaigns consist of 84 soil samples (28 per treatment) collected from permanent plots for quantification of soil biota (invertebrates determined by microscopy and bacteria by 16S rRNA sequencing) and intensive geochemical analyses. This experiment will address the overarching hypothesis: Climate warming in the McMurdo Dry Valleys will amplify connectivity among landscape units leading to enhanced coupling of nutrient cycles across landscapes, and increased biodiversity and productivity. Soil samples were taken for organism enumeration and moisture content analysis as follows: Sampling bags were prepared with one sterile Whirlpak bag and clean plastic scoop per sample. Samples were taken from within the 1m2 area of each plot. The location of the sampling was recorded each year so that areas were not re-sampled. Using the plastic scoop, soil was collected to 10 cm depth. Very large rocks (more than 20 mm diameter) were excluded from the sample. The soil was shoveled into the Whirlpak bag ...
Sampling campaigns consist of 84 soil samples (28 per treatment) collected from permanent plots for quantification of soil biota (invertebrates determined by microscopy and bacteria by 16S rRNA sequencing) and intensive geochemical analyses. This experiment will address the overarching hypothesis: Climate warming in the McMurdo Dry Valleys will amplify connectivity among landscape units leading to enhanced coupling of nutrient cycles across landscapes, and increased biodiversity and productivity. Soil samples were taken for organism enumeration and moisture content analysis as follows: Sampling bags were prepared with one sterile Whirlpak bag and clean plastic scoop per sample. Samples were taken from within the 1m2 area of each plot. The location of the sampling was recorded each year so that areas were not re-sampled. Using the plastic scoop, soil was collected to 10 cm depth. Very large rocks (more than 20 mm diameter) were excluded from the sample. The soil was shoveled into the Whirlpak bag ...
More modeling madness projecting the future, but the actual data for the past 30 years says otherwise, with a positive trend. Regular commenter Julienne Stroeve of NSIDC is one of the co-authors, so perhaps shell weigh in here. The article says They selected the five models that most closely reproduced changes in actual Antarctic sea…
From the British Antarctic Survey New climate history adds to understanding of recent Antarctic Peninsula warming Results published this week by a team of polar scientists from Britain, Australia and France adds a new dimension to our understanding of Antarctic Peninsula climate change and the likely causes of the break-up of its ice shelves. The…
Antarctic shallow‐water invertebrates are exceptional candidates to study population genetics and evolution, because of their peculiar evolutionary history and adaptation to extreme habitats that expand and retreat with the ice sheets. Among them, sponges are one of the major components, yet population connectivity of none of their many Antarctic species has been studied. To investigate gene flow, local adaptation and resilience to near‐future changes caused by global warming, we sequenced 62 individuals of the sponge Dendrilla antarctica along the Western Antarctic Peninsula (WAP) and the South Shetlands (spanning ~900 km). We obtained information from 577 double digest restriction site‐associated DNA sequencing (ddRADseq)‐derived single nucleotide polymorphism (SNP), using RADseq techniques for the first time with shallow‐water sponges. In contrast to other studies in sponges, our 389 neutral SNPs data set showed high levels of gene flow, with a subtle substructure driven by the ...
Article: Bush Claims More Power Than King George III or Cromwelll - President Bush has claimed powers for himself that are not only unconstitutional but exceed those papers assumed by Oliver Cromwell and King George III.
Antarctic ice core records have provided unprecedented information on past climatic changes and forcing factors on decadal to millennial timescales. The glaciochemical and stable isotope records of a
The 16S rRNAs of nine new species of prokaryotes, that had been isolated from four lakes of the Vestfold Hills, have been sequenced. These sequences were compared with those of their closest taxonomic relatives available from publicly available databases. The Antarctic species were of wide diversity with representatives from the domains Archaea and Bacteria (sensu Woese). Generally, they were most closely related to organisms from marine environments. The sequence dissimilarity between the rRNA sequences of the Antarctic strains and their nearest known relatives suggest they diverged from each other much earlier than the establishment of their modern Antarctic habitat. The conserved nature of the 16S rRNA molecule suggests it may not be as useful for detecting evolutionary change in Antarctic prokaryotes as distinct from non-Antarctic prokaryotes. Although the optimal temperature for growth of each species is well above the temperature of its environment, each has a reduced optimal temperature ...
DIVERSIDAD MICROBIANA. Heavy metals in sediments and soft tissues of the Antarctic clam Laternula elliptica: more evidence as possible biomonitor of coastal marine pollution at high latitute? Vodopivez C, Curtosi A, Villaamil E, Smichowsky P, Pelletier E,. MacCormack W. Science of the Total Environment 502, 375-384, 2015 (ISSN: 0048-9697). http://www.sciencedirect.com/science/article/pii/S0048969714013412?via%3Dihub. Molecular characterization of anthropogenic sources of sedimentary organic matter from Potter Cove, King George Island, Antarctica. Dauner ALL, Hernández E, Mac Cormack WP, Martins CC. Science of the Total Environment (ISSN: 0048-9697) 502, 408-416, 2015. http://www.sciencedirect.com/science/article/pii/S0048969714013655. Marine Archaeal community structure from Potter Cove, Antarctica: high temporal and spatial dominance of the phylum Thaumarcheota. Hernández EA, Piquet AM-T, Lopez JL, Buma AGJ, Mac Cormack WP. Polar Biology (ISSN:0722-4060) 38 (2), 117-130, ...
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A new study published in the journal Nature reveals that Arctic and Antarctic waters, not tropical reefs, are hot spots for the birth of new species of life.
The territory includes Amsterdam Island, Saint-Paul Island, Crozet Islands, and the Kerguelen Islands in the southern Indian Ocean near 43°S, 67°E, along with Adélie Land, the sector of Antarctica claimed by France, named by the French explorer Jules Dumont dUrville after his wife. Adélie Land (about 432,000 km2 or 167,000 sq mi) and the islands, totaling 7,781 km2 (3,004 sq mi), have no indigenous inhabitants, though in 1997 there were about 100 researchers whose numbers varied from winter (July) to summer (January). Amsterdam Island and Saint-Paul Island are extinct volcanoes and have been delineated as the Amsterdam and Saint-Paul Islands temperate grasslands ecoregion. The highest point in the territory is Mont Ross on Kerguelen Island at 1,850 m (6,070 ft). There are very few airstrips on the islands, only existing on islands with weather stations, and the 1,232 km (766 mi) of coastline have no ports or harbors, only offshore anchorages. ...
Figure 2. Temperature anomalies averaged over the Southern Hemisphere (top), temperatures from the sub-Antarctic station Orcadas (middle), and hydrogen isotopes (a proxy for temperature) from James Ross Island on the Antarctic Peninsula (bottom). All the data are publicly available: GISS, SCAR, Nature. Why the ambiguity? After all, the results show that its now warmer on James Ross Island now than it has been at any time during at least the last millennium (see Figure 2), and its unequivocal that this recent warmth led to the demise of ice shelves in the area over the last few decades. Moreover, the rate of recent century-scale warming is at the upper limit of rates in the pre-anthropogenic era: Mulvaney et al. find that the most recent warming is faster than 99.7% of any other given 100-year period in the last 2000 years. Why then, doesnt this lead simply to the conclusion that this that recent warming and associated ice shelf collapse and glacier acceleration on the Antartic Pensinula is the ...
Fountain, A. G., G. L. Dana, K. J. Lewis, B. H. Vaughn, and D. M. McKnight (1998), Glaciers of the McMurdo Dry Valleys, southern Victoria Land, Antarctica, in Ecosystem Dynamics in a Polar Desert, the McMurdo Dry Valleys, Antarctica, edited by J. C. Priscu, pp. 65-76, Antarct. Res. Ser., vol. 72, AGU, Washington, D. C. ...
The Antarctic notothenioid Trematomus bernacchii (rock cod) lives at a constant mean temperature of - 1.9 °C. Gastric digestion under these conditions relies on the proteolytic activity of aspartic proteases such as pepsin. To understand the molecular mechanisms of Antarctic fish pepsins, T. bernacchii pepsins A1 and A2 were cloned, overexpressed in Escherichia coli, purified and characterized wit ...
All members of this group have to be fairly well adapted for the cold and you would think that they would have to be fairly warm blooded fish. Chaenocephalus aceratus is more of a no blooded fish. It is the only vertebrate to have lost its blood. It still has a sort of translucent liquid made of of plasma pumping through its veins, but it has no blood cells and not even haemoglobin is present. Haemoglobin is the molecule vertebrates use to carry Oxygen around the body. Plasma can carry a limited amount of Oxygen, but it is only 10% as efficient. To make up for this Chaenocephalus aceratus has an enormous heart and a higher volume of blood. This raises the question as to why they would loose rid of their blood. It doesnt give them an advantage in surviving the cold. I cant really answer that convincingly ...