scholarly journals Gelifluction and Thixotropy of Maritime Antarctic Soils: Small-Scale Measurements with a Rotational Rheometer

2016 ◽  
Vol 28 (1) ◽  
pp. 314-321
Author(s):  
Benhua Sun ◽  
Paul G. Dennis ◽  
Kevin K. Newsham ◽  
David W. Hopkins ◽  
Paul D. Hallett
Keyword(s):  
Small Scale ◽  
Maritime Antarctic ◽  
Rotational Rheometer ◽  
Antarctic Soils

scholarly journals Penguins significantly increased phosphine formation and phosphorus contribution in maritime Antarctic soils

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Renbin Zhu ◽  
Qing Wang ◽  
Wei Ding ◽  
Can Wang ◽  
Lijun Hou ◽  
...  
Keyword(s):  
Maritime Antarctic ◽  
Antarctic Soils

scholarly journals CO2-C losses and carbon quality of selected Maritime Antarctic soils

2012 ◽  
Vol 25 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Juliana Vanir De Souza Carvalho ◽  
Eduardo De Sá Mendonça ◽  
Newton La Scala ◽  
César Reis ◽  
Efrain Lázaro Reis ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Temperature ◽  
Soil Carbon ◽  
Humic Substances ◽  
Microbial Activity ◽  
Chemical Characteristics ◽  
Maritime Antarctic ◽  
Antarctic Soils ◽  
Humification Degree

AbstractPolar Regions are the most important soil carbon reservoirs on Earth. Monitoring soil carbon storage in a changing global climate context may indicate possible effects of climate change on terrestrial environments. In this regard, we need to understand the dynamics of soil organic matter in relation to its chemical characteristics. We evaluated the influence of chemical characteristics of humic substances on the process of soil organic matter mineralization in selected Maritime Antarctic soils. A laboratory assay was carried out with soils from five locations from King George Island. We determined the contents of total organic carbon, oxidizable carbon fractions of soil organic matter, and humic substances. Two in situ field experiments were carried out during two summers, in order to evaluate the CO2-C emissions in relation to soil temperature variations. The overall low amounts of soil organic matter in Maritime Antarctic soils have a low humification degree and reduced microbial activity. CO2-C emissions showed significant exponential relationship with temperature, suggesting a sharp increase in CO2-C emissions with a warming scenario, and Q10 values (the percentage increase in emission for a 10°C increase in soil temperature) were higher than values reported from elsewhere. The sensitivity of the CO2-C emission in relation to temperature was significantly correlated with the humification degree of soil organic matter and microbial activity for Antarctic soils.

scholarly journals Impact of expected global warming on C mineralization in maritime Antarctic soils: results of laboratory experiments

2010 ◽  
Vol 22 (5) ◽  
pp. 485-493 ◽  
Author(s):  
Juliana Vanir de Souza Carvalho ◽  
Eduardo de Sá Mendonça ◽  
Rui Tarcísio Barbosa ◽  
Efrain Lázaro Reis ◽  
Paulo Negrais Seabra ◽  
...  
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Incubation Temperature ◽  
Structural Characteristics ◽  
Maritime Antarctic ◽  
Organic C ◽  
Antarctic Soils ◽  
Mineral Soils ◽  
Increasing Temperature

AbstractThis study concerned the fragility of maritime Antarctic soils under increasing temperature, using the C dynamics and structural characteristics of humic substances as indicators. Working with four representative soils from King George Island (Lithic Thiomorphic Cryosol (LTC1 and LTC2), Ornithogenic Cryosol (OG) and Gelic Organosol (ORG)) we evaluated the total organic C and nitrogen contents, the oxidizable C and humic substances. Soil samples were incubated to assess the amount of C potentially mineralizable at temperatures typical of an Antarctic summer (5–14°C). Humic acids showed a higher aliphatic character and a smaller number of condensed aromatic groups, which suggests that these molecules from Antarctic soils are generally less resistant to microbial degradation than humic acids molecules from other regions. Based on 13C NMR spectra of MAS and CP/MAS, samples of soil humic acids of mineral soils (LTC1 and LTC2) have a higher content of aliphatic C, and heteroatom C, with lower levels of carbonyl and aromatic C, when compared with organic matter-rich soils (OG and ORG). Increasing incubation temperature led to a higher rate of mineralizable C in all soils. A sequence of soil fragility was suggested - LTC1 and LTC2 > OG > ORG - which showed a correlation with the Q10 coefficient and the ratio of labile and recalcitrant C fractions of soil organic matter (R2 = 0.83).

scholarly journals Predicting climate change impacts on maritime Antarctic soils: a space-for-time substitution study

2020 ◽  
Vol 141 ◽  
pp. 107682 ◽  
Author(s):  
C.A. Horrocks ◽  
K.K. Newsham ◽  
F. Cox ◽  
M.H. Garnett ◽  
C.H. Robinson ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Change Impacts ◽  
Maritime Antarctic ◽  
Antarctic Soils ◽  
Time Substitution

Hg distribution and speciation in Antarctic soils of the Fildes and Ardley peninsulas, King George Island

2012 ◽  
Vol 24 (4) ◽  
pp. 395-407 ◽  
Author(s):  
Renato Pereira De Andrade ◽  
Roberto Ferreira Machado Michel ◽  
Carlos Ernerto Gonçalves Reynaud Schaefer ◽  
Felipe Nogueira Bello Simas ◽  
Cláudia Carvalhinho Windmöller
Keyword(s):  
Organic Matter ◽  
Solid Phase ◽  
Soil Depth ◽  
Close Correlation ◽  
Chemical Fractionation ◽  
King George Island ◽  
Maritime Antarctic ◽  
Antarctic Soils ◽  
Ornithogenic Soils ◽  
The Antarctic

AbstractData on the content and speciation of mercury (Hg) in the soils of Antarctica are scarce and vary greatly between the regions studied, but overall Hg concentrations found were generally very low. We investigated the Hg quantity and speciation by solid-phase Hg pyrolysis and chemical fractionation in selected maritime Antarctic soils, comparing ornithogenic and non-ornithogenic areas of the Fildes and Ardley peninsulas of King George Island. The total Hg contents ranged from 4.3–256 ng g-1, and values for ornithogenic soils were the highest recorded for Antarctic soils. A close correlation between Hg and organic matter was observed in the ornithogenic soils, with levels decreasing with depth. In the non-ornithogenic soils, a correlation between Hg content and soil depth was also observed, but the values were found to increase with depth. Thermograms showed that all Hg was in the 2+ oxidation state and was predominantly linked to organic matter, corroborating the chemical fractionation results for the ornithogenic soils. These results show the need for further refined studies about the interactions of Hg with organic matter in order to better understand the biogeochemistry of this metal in the Antarctic environment.

Fungal diversity in maritime Antarctic soils determined using a combination of culture isolation, molecular fingerprinting and cloning techniques

Polar Biology ◽  
2005 ◽  
Vol 29 (7) ◽  
pp. 552-561 ◽  
Author(s):  
Elaine Malosso ◽  
Ian S. Waite ◽  
Lorna English ◽  
David W. Hopkins ◽  
Anthony G. O’Donnell
Keyword(s):  
Fungal Diversity ◽  
Molecular Fingerprinting ◽  
Maritime Antarctic ◽  
Antarctic Soils

Experimental warming of bryophytes increases the population density of the nematode Plectus belgicae in maritime Antarctica

2020 ◽  
pp. 1-9
Author(s):  
Kevin K. Newsham ◽  
Richard J. Hall ◽  
N. Rolf Maslen
Keyword(s):  
Population Density ◽  
Food Webs ◽  
Interactive Effects ◽  
Experimental Warming ◽  
Maritime Antarctic ◽  
Population Densities ◽  
Maritime Antarctica ◽  
Antarctic Soils ◽  
Sanionia Uncinata ◽  
Adelaide Island

Abstract Despite nematodes routinely being the most frequent soil- and bryophyte-associated animals in maritime Antarctica, there is a lack of clarity about the influence of warming on their populations in the region. Here, we report the results of a field experiment on Adelaide Island that tested the effects of warming with open-top chambers (OTCs) for 37 months on nematodes associated with the bryophytes Cephaloziella varians and Sanionia uncinata. Over the experiment's duration, OTCs increased the population density of the nematode Plectus belgicae in mats of both bryophytes by six-fold, with four- to seven-fold increases in the abundances of male, female and juvenile P. belgicae in warmed mats, and with the largest effects on the abundances of juveniles. Despite C. varians, which is black in colour, warming to a greater extent than S. uncinata during summer, no interactive effects of OTCs and bryophyte species were recorded on the population density of P. belgicae. Our results corroborate a previous study showing that warming increases Plectus population densities in maritime Antarctic soils, with implications for the region's terrestrial food webs.

scholarly journals Molecular Analysis of Geographic Patterns of Eukaryotic Diversity in Antarctic Soils

2004 ◽  
Vol 70 (10) ◽  
pp. 5963-5972 ◽  
Author(s):  
Blair Lawley ◽  
Sarah Ripley ◽  
Paul Bridge ◽  
Peter Convey
Keyword(s):  
Maritime Antarctic ◽  
Southern Limit ◽  
Antarctic Soils ◽  
Eukaryotic Diversity ◽  
Plant Groups ◽  
Reverse Pattern ◽  
Scotia Arc ◽  
Study Sites ◽  
Taxonomic Groups ◽  
High Level

ABSTRACT We describe the application of molecular biological techniques to estimate eukaryotic diversity (primarily fungi, algae, and protists) in Antarctic soils across a latitudinal and environmental gradient between approximately 60 and 87°S. The data were used to (i) test the hypothesis that diversity would decrease with increasing southerly latitude and environmental severity, as is generally claimed for “higher” faunal and plant groups, and (ii) investigate the level of endemicity displayed in different taxonomic groups. Only limited support was obtained for a systematic decrease in diversity with latitude, and then only at the level of a gross comparison between maritime (Antarctic Peninsula/Scotia Arc) and continental Antarctic sites. While the most southerly continental Antarctic site was three to four times less diverse than all maritime sites, there was no evidence for a trend of decreasing diversity across the entire range of the maritime Antarctic (60 to 72°S). Rather, we found the reverse pattern, with highest diversity at sites on Alexander Island (ca. 72°S), at the southern limit of the maritime Antarctic. The very limited overlap found between the eukaryotic biota of the different study sites, combined with their generally low relatedness to existing sequence databases, indicates a high level of Antarctic site isolation and possibly endemicity, a pattern not consistent with similar studies on other continents.

scholarly journals Effects of penguin guano and moisture on nitrogen biological fixation in maritime Antarctic soils

Polar Biology ◽  
2016 ◽  
Vol 40 (2) ◽  
pp. 437-448 ◽  
Author(s):  
Cecilia A. Pérez ◽  
Juan C. Aravena ◽  
Cristóbal Ivanovich ◽  
Robert McCulloch
Keyword(s):  
Maritime Antarctic ◽  
Biological Fixation ◽  
Antarctic Soils

Reasons to strike first

2019 ◽  
Vol 42 ◽  
Author(s):  
William Buckner ◽  
Luke Glowacki
Keyword(s):  
Intergroup Conflict ◽  
Small Scale

Abstract De Dreu and Gross predict that attackers will have more difficulty winning conflicts than defenders. As their analysis is presumed to capture the dynamics of decentralized conflict, we consider how their framework compares with ethnographic evidence from small-scale societies, as well as chimpanzee patterns of intergroup conflict. In these contexts, attackers have significantly more success in conflict than predicted by De Dreu and Gross's model. We discuss the possible reasons for this disparity.

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