Nitrate and ammonium ions contents in field minibioreactors with Antarctic freshwater autotrophs

2013 ◽  
Vol 3 (2) ◽  
pp. 196-207
Author(s):  
Pavel Coufalík ◽  
Peter Váczi ◽  
Ondřej Zvěřina ◽  
Kateřina Trnková ◽  
Kateřina Skácelová ◽  
...  
Keyword(s):  
Small Volume ◽  
Field Experiments ◽  
Rapid Development ◽  
Nitrogen Forms ◽  
Ammonium Ions ◽  
Nutrient Environment ◽  
External Conditions ◽  
James Ross Island ◽  
The Antarctic ◽  
Johann Gregor Mendel

The content of nitrate and ammonium ions in aquatic environment is an important factor in the development of microorganisms colonies especially in low-nutrient environment. In this study, field experiments using small-volume minibioreactors were performed directly on the James Ross Island in Antarctica in order to describe changes in nitrate and ammonium ions contents in the Antarctic environment The ion concentrations in minibioreactors with local freshwater autotrophs was monitored for increased eutro-phication conditions. The content of nitrogen forms was determined in water samples taken from the minibioreactors regularly. Samples were taken to the laboratory of the Johann Gregor Mendel station where nitrogen content was evaluated using ion-selective electrodes. Furthermore, the freshwater autotrophs was subjected to basic taxonomic study. Closed system of the minibioreactors allowed the monitoring of nitrogen speciation changes which take place in the environment. These changes can be attributed to both the biological activity of microorganisms and external conditions. Increased eutrophication of water did not induce a rapid development of the freshwater autotrophs.

Microbial diversity of internal environment of Johann Gregor Mendel Station, Antarctica

2011 ◽  
Vol 1 (1) ◽  
pp. 34-41
Author(s):  
Alena Ševčíková ◽  
Jana Bednářová ◽  
Sonia Bartáková ◽  
Pavel Ševčík
Keyword(s):  
Research Station ◽  
Quiescent State ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Microbial Profile ◽  
James Ross Island ◽  
Gregor Mendel ◽  
The Antarctic ◽  
Johann Gregor Mendel

During January and February 2011 two sets of microbiological samples were collected inside the main building of Johann Gregor Mendel station located at the James Ross Island near the coast of Antarctica. The aim was to examine the changes of microbial profile of the antarctic station environment. The first set of samples was collected from the station environment before the staff entry, i.e. after 10 months of quiescent state when nobody was present at the station. The second set of samples was collected from the same places before the Antarctic expedition staff left the station after 45 days of the stay. The cultivation of samples was focused on mesophilic bacteria. Twenty-three strains were obtained from the Set No. 1 and 27 strains were obtained from the Set No. 2. However, 8 strains from each set were not reliably identified by mass spectrometry. Altogether 13 strains of Gram-positive bacteria were identified in the Set. No. 1, while only 7 in the Set No. 2. Contrastingly, Gram-negative bacteria were much more abundant in the Set No. 2 (12 strains) than in the Set No. 1 (2 strains). Bacillus sp. was the most common Gram-positive strain (9 isolations from the first set, 2 isolations from the second set). Pantoea agglomerans was the most common Gram-negative strain (2 isolations from the first set, 7 isolations from the second set). The first experience with the microbial profile of the research station showed that we were able to detect mainly bacteria commonly present in the outer environment that could survive under extreme conditions. We did not isolate any microbes related to human colonisation except of enterococci and Escherichia vulneris. For further investigation of the station environment, it will be necessary to choose alternative way of collection and storage of samples to ensure survival of all present bacteria.

scholarly journals Decentralized 3D Collision Avoidance for Multiple UAVs in Outdoor Environments

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4101 ◽  
Author(s):  
Eduardo Ferrera ◽  
Alfonso Alcántara ◽  
Jesús Capitán ◽  
Angel Castaño ◽  
Pedro Marrón ◽  
...  
Keyword(s):  
Collision Avoidance ◽  
System Integration ◽  
Field Experiments ◽  
Positioning Systems ◽  
Wind Gusts ◽  
Aerial Vehicles ◽  
Multiple Uavs ◽  
Outdoor Environments ◽  
External Conditions ◽  
Field Experimentation

The use of multiple aerial vehicles for autonomous missions is turning into commonplace. In many of these applications, the Unmanned Aerial Vehicles (UAVs) have to cooperate and navigate in a shared airspace, becoming 3D collision avoidance a relevant issue. Outdoor scenarios impose additional challenges: (i) accurate positioning systems are costly; (ii) communication can be unreliable or delayed; and (iii) external conditions like wind gusts affect UAVs’ maneuverability. In this paper, we present 3D-SWAP, a decentralized algorithm for 3D collision avoidance with multiple UAVs. 3D-SWAP operates reactively without high computational requirements and allows UAVs to integrate measurements from their local sensors with positions of other teammates within communication range. We tested 3D-SWAP with our team of custom-designed UAVs. First, we used a Software-In-The-Loop simulator for system integration and evaluation. Second, we run field experiments with up to three UAVs in an outdoor scenario with uncontrolled conditions (i.e., noisy positioning systems, wind gusts, etc). We report our results and our procedures for this field experimentation.

Chapter 3.2b Bransfield Strait and James Ross Island: petrology

2021 ◽  
pp. M55-2018-37 ◽  
Author(s):  
Karsten M. Haase ◽  
Christoph Beier
Keyword(s):  
Antarctic Peninsula ◽  
South Shetland Island ◽  
The South ◽  
Bransfield Strait ◽  
Geodynamic Processes ◽  
James Ross Island ◽  
South Shetland Trench ◽  
Low Degrees ◽  
Back Arc ◽  
The Antarctic

AbstractYoung volcanic centres of the Bransfield Strait and James Ross Island occur along back-arc extensional structures parallel to the South Shetland island arc. Back-arc extension was caused by slab rollback at the South Shetland Trench during the past 4 myr. The variability of lava compositions along the Bransfield Strait results from varying degrees of mantle depletion and input of a slab component. The mantle underneath the Bransfield Strait is heterogeneous on a scale of approximately tens of kilometres with portions in the mantle wedge not affected by slab fluids. Lavas from James Ross Island east of the Antarctic Peninsula differ in composition from those of the Bransfield Strait in that they are alkaline without evidence for a component from a subducted slab. Alkaline lavas from the volcanic centres east of the Antarctic Peninsula imply variably low degrees of partial melting in the presence of residual garnet, suggesting variable thinning of the lithosphere by extension. Magmas in the Bransfield Strait form by relatively high degrees of melting in the shallow mantle, whereas the magmas some 150 km further east form by low degrees of melting deeper in the mantle, reflecting the diversity of mantle geodynamic processes related to subduction along the South Shetland Trench.

scholarly journals Modelling temperature variations in polar snow using DAISY

1997 ◽  
Vol 43 (143) ◽  
pp. 180-191 ◽  
Author(s):  
Ε. M. Morris ◽  
H. -P. Bader ◽  
P. Weilenmann
Keyword(s):  
Field Experiments ◽  
A Priori ◽  
Model Parameters ◽  
Data Set ◽  
International Geophysical Year ◽  
Snow Model ◽  
Using Data ◽  
Polar Snow ◽  
Parameter Values ◽  
The Antarctic

AbstractA physics-based snow model has been calibrated using data collected at Halley Bay, Antarctica, during the International Geophysical Year. Variations in snow temperature and density are well-simulated using values for the model parameters within the range reported from other polar field experiments. The effect of uncertainty in the parameter values on the accuracy of the predictions is no greater than the effect of instrumental error in the input data. Thus, this model can be used with parameters determined a priori rather than by optimization. The model has been validated using an independent data set from Halley Bay and then used to estimate 10 m temperatures on the Antarctic Peninsula plateau over the last half-century.

scholarly journals Surface Albedo of the Antarctic Sea Ice Zone

2005 ◽  
Vol 18 (17) ◽  
pp. 3606-3622 ◽  
Author(s):  
Richard E. Brandt ◽  
Stephen G. Warren ◽  
Anthony P. Worby ◽  
Thomas C. Grenfell
Keyword(s):  
Sea Ice ◽  
Surface Albedo ◽  
Near Infrared ◽  
Field Experiments ◽  
Climate Models ◽  
Solar Spectrum ◽  
Open Water ◽  
Visual Observation ◽  
Antarctic Sea Ice ◽  
The Antarctic

Abstract In three ship-based field experiments, spectral albedos were measured at ultraviolet, visible, and near-infrared wavelengths for open water, grease ice, nilas, young “grey” ice, young grey-white ice, and first-year ice, both with and without snow cover. From the spectral measurements, broadband albedos are computed for clear and cloudy sky, for the total solar spectrum as well as for visible and near-infrared bands used in climate models, and for Advanced Very High Resolution Radiometer (AVHRR) solar channels. The all-wave albedos vary from 0.07 for open water to 0.87 for thick snow-covered ice under cloud. The frequency distribution of ice types and snow coverage in all seasons is available from the project on Antarctic Sea Ice Processes and Climate (ASPeCt). The ASPeCt dataset contains routine hourly visual observations of sea ice from research and supply ships of several nations using a standard protocol. Ten thousand of these observations, separated by a minimum of 6 nautical miles along voyage tracks, are used together with the measured albedos for each ice type to assign an albedo to each visual observation, resulting in “ice-only” albedos as a function of latitude for each of five longitudinal sectors around Antarctica, for each of the four seasons. These ice albedos are combined with 13 yr of ice concentration estimates from satellite passive microwave measurements to obtain the geographical and seasonal variation of average surface albedo. Most of the Antarctic sea ice is snow covered, even in summer, so the main determinant of area-averaged albedo is the fraction of open water within the pack.

scholarly journals Variations of glacier frontal positions on the northern Antarctic Peninsula

2004 ◽  
Vol 39 ◽  
pp. 525-530 ◽  
Author(s):  
Frank Rau ◽  
Fabian Mauz ◽  
Hernán De Angelis ◽  
Ricardo Jaña ◽  
Jorge Arigony Neto ◽  
...  
Keyword(s):  
Antarctic Peninsula ◽  
Thermal Emission ◽  
General Trend ◽  
Glacier Recession ◽  
Research Initiative ◽  
Glacier Front ◽  
James Ross Island ◽  
Investigation Period ◽  
The Antarctic ◽  
Local Accumulation

AbstractChanges in the ice fronts on the Antarctic Peninsula north of 70˚ S are currently being investigated through a comprehensive analysis of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Landsat Thematic Mapper (TM) data as part of the international research initiative ‘Global land Ice Measurements from Space’ (GLIMS). Regional case studies are presented that cover a variety of glacial systems distributed over the northern Antarctic Peninsula and provide data on glacier front variations during the period 1986–2002. The results confirm a general trend of regional glacier front recession, but a range of different glacier variations are observed throughout the study area. Areas of predominant retreat are located in the northeastern and southwestern sectors, while stationary ice fronts characterize glacial behaviour on the northwestern coast of the peninsula. In addition, a significant increase in glacier recession is identified on James Ross Island, where retreat rates doubled during the period 1988–2001 compared to the previous investigation period, 1975–88. These observations are interpreted as being direct consequences of the rapidly changing climate in the region, which differentially affects the local accumulation and ablation patterns of the glacial systems.

Nautilids from the Upper Cretaceous of the James Ross Basin, Antarctic Peninsula

2005 ◽  
Vol 17 (2) ◽  
pp. 267-280 ◽  
Author(s):  
MARCELA CICHOWOLSKI ◽  
ALFREDO AMBROSIO ◽  
ANDREA CONCHEYRO
Keyword(s):  
New Species ◽  
Antarctic Peninsula ◽  
Upper Cretaceous ◽  
Single Species ◽  
Central Chile ◽  
James Ross Island ◽  
The Antarctic ◽  
First Time ◽  
A New Species ◽  
Lower Campanian

To date, Cretaceous nautilids from the Antarctic Peninsula have received little attention and only a single species had been reported, Eutrephoceras simile Spath, from Seymour, Snow Hill, and James Ross islands. Currently, it is considered a synonym of Eutrephoceras subplicatum (Steinmann), which has also been described from the Upper Cretaceous of central Chile, southern Argentina and Angola. Here, we report and describe E. subplicatum in detail, based on specimens from the Lower Campanian–Maastrichtian of Vega, Seymour and James Ross islands, presenting, for the first time, embryonic conch features related to the palaeoecology of these organisms. The nauta of this species had a diameter of approximately 30 mm with 5–6 septa. In addition, we describe a new species, Eutrephoceras antarcticum, and one specimen assigned to the same genus in open nomenclature, both recovered from the Lower Campanian beds of James Ross Island.

A new method for characterising the Antarctic Circumpolar Currents using Argo float temperature and salinity profiles

2020 ◽  
Author(s):  
Luke Roberts ◽  
Rhiannon Jones ◽  
Matthew Donnelly ◽  
Katharine Hendry
Keyword(s):  
High Resolution ◽  
Southern Ocean ◽  
Data Processing ◽  
Rapid Development ◽  
Regional Scale ◽  
Global Ocean ◽  
Argo Float ◽  
Oceanographic Data ◽  
The University ◽  
The Antarctic

<p>Argo is an array of automated profiling floats, which have allowed the rapid development of high-resolution and high-quality oceanographic data acquisition. The international program has been in operation since the 1990s providing continuous hydrographic data globally. There are now over a million individual float profiles, contributing to our understanding of global ocean physical properties, such as circulation processes at both a local and regional scale. With these innovations come the challenges of data processing, and compilation of user-friendly data products. For example, the Southern Ocean is a critical region that modulates our climate, via heat exchange, carbon storage, biogeochemistry, and primary productivity. An improved quantified understanding of Southern Ocean currents, informed by Argo, must be implemented in policy-relevant high-resolution climate models to advance our understanding of future change.</p><p> </p><p>In May 2019, a new collaboration was formed between the Southern Ocean Argo Resource Centre (British Oceanographic Data Centre) and the University of Bristol. The aims were two-fold: to produce a method for characterising Southern Ocean frontal zones using Argo floats, and to train early career researchers in the University sector in data processing and management. We have created a publicly available code that characterises physical features of the Antarctic Circumpolar Current using Argo float profiles, using minimal software, and without the need to access high-performance computers. The code categorises each profile based on the temperature and salinity ‘fingerprints’ of zones between each Southern Ocean front. This allows the user to produce output surface plots from user-specified time-slices and geographic areas, and so compare frontal movement in time and space.</p>

Ten new Bacillariophyta species from James Ross Island and the South Shetland Islands (Maritime Antarctic Region)

Phytotaxa ◽  
2016 ◽  
Vol 272 (1) ◽  
pp. 37 ◽  
Author(s):  
RALITSA ZIDAROVA ◽  
KATEŘINA KOPALOVÁ ◽  
BART VAN DE VIJVER
Keyword(s):  
New Species ◽  
South Shetland Islands ◽  
Similar Species ◽  
Maritime Antarctic ◽  
The South ◽  
Antarctic Region ◽  
Shetland Islands ◽  
James Ross Island ◽  
The Antarctic

The present paper describes 10 new diatom (Bacillariophyta) species from the Maritime Antarctic Region. Five of the newly described taxa: Caloneis australis sp. nov., Mayamaea sweetloveana sp. nov., Navicula romanedwardii sp. nov., Sellaphora antarctica sp. nov. and Sellaphora gracillima sp. nov. have been previously reported from the Antarctic Region but were force-fitted into incorrect names. Five other taxa: Chamaepinnularia elliptica sp. nov., Cosmioneis regigeorgiensis sp. nov., Mayamaea tytgatiana sp. nov., Muelleria pimpireviana sp. nov. and Pinnularia pinseeliana sp. nov. are newly discovered taxa. The morphology of all new species is studied using both light and scanning electon microscope observations and compared with similar species from the Antarctic Region and worldwide. Data about the ecology and confirmed Antarctic distribution of the new species are added.

Late Miocene Asterozoans (Echinodermata) in the James Ross Island Volcanic Group

2006 ◽  
Vol 18 (1) ◽  
pp. 117-122 ◽  
Author(s):  
Mark Williams ◽  
John L. Smellie ◽  
Joanne S. Johnson ◽  
Daniel B. Blake
Keyword(s):  
Antarctic Peninsula ◽  
Late Miocene ◽  
Volcanic Group ◽  
Antarctic Marine ◽  
Morphological Detail ◽  
James Ross Island ◽  
Ecology And Environment ◽  
Fossil Data ◽  
Glaciomarine Sediments ◽  
The Antarctic

Asterozoans (Echinodermata) of Late Miocene age (6.02 ± 0.12 Ma) are preserved as external moulds in water-lain tuffs of the James Ross Island Volcanic Group (JRIVG), James Ross Island, Antarctic Peninsula. The asterozoans are complete, and appear to represent specimens suffocated after having been pinioned by rapid sedimentation on the distal fringe of an erupting sub-aqueous tuff cone. Although the coarse nature of the host sediments has obliterated the fine morphological detail of the specimens, at least one suggests evidence of entrainment by a turbidity current. A second shows evidence of detachment of the distal tip of one of its arms. In addition to fossil discoveries from glaciomarine sediments, the volcanic tuffs of the JRIVG represent a new source of fossil data that can be used to interpret the ecology and environment of the Antarctic marine shelf biota during the Neogene.

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