Found 14112 items
1 January, 2000
Fourier-transform laser Raman spectroscopy in the near infrared (1064 nm) has been used to characterize a variety of key pigments and biomolecules produced by cyanobacteria and other stress-tolerant microbes in…1 January, 2000
Lichens are found at the limits of polar life in the Antarctic Dry Valleys under extreme conditions of UVB radiation, desiccation and low temperature. They may even have evolved in…Read more on Lichens at the limits of life: past perspectives and modern technology
1 January, 2000 by Martin Collins
The commensal relationship between a snailfish, tentatively identified as Careproctus sp. (Osteichthyes: Liparidae), and the lithodid crab Paralomis formosa (Crustacea: Lithodidae) was photographed in situ using a baited camera vehicle,…1 January, 2000
The validity of a radiative transfer model can be checked either by comparing its results with measurements or with solutions for artificial cases. Unfortunately, neither type of comparison can guarantee…Read more on From model intercomparison toward benchmark UV spectra for six real atmospheric cases
1 January, 2000
Samples were collected from the top 200 m of the water column at 50 stations during two cruises in different, near equinoctial seasons on an Atlantic transect near the 20°W…Read more on Bacterial growth and grazing loss in contrasting areas of North and South Atlantic
1 January, 2000
Krill, or euphausiids, a group of immense importance in marine ecosystems, comprises over 80 species, most of which are planktonic. Krill are widespread with species to be found in all…1 January, 2000
A series of experiments was carried out in February 1999 at South Georgia (Subarea 48.3) to examine the effects of different weighting regimes on the incidental mortality of birds caught…1 January, 2000 by Michael Pinnock
The Super Dual Auroral Radar Network (SuperDARN) radars are proving to be a very powerful experimental tool for exploring solar wind-magnetosphere-ionosphere interactions. They measure the autocorrelation function (ACF) of the…1 January, 2000 by Lloyd Peck
Antarctic anemones of the genus Halcampoides inhabit low intertidal and shallow subtidal zones. They readily burrow into soft sediments following disturbance. The process of re-burying was recorded using time-lapse video…Read more on Burrowing in the Antarctic anemone, Halcampoides sp., from Signy Island, Antarctica
1 January, 2000
Large, biomass-dominant Southern Ocean copepod species have been much studied, but small and mesopelagic species also play major rôles in these ecosystems. However, little is known of some basic aspects…1 January, 2000
Excretion by Antarctic krill Euphausia superba (hereafter ‘‘krill’’) is measured typically in small containers of filtered seawater for 12–24 h, which may cause a reduction of swimming, feeding, and metabolism.…Read more on Ammonium excretion by Antarctic krill Euphausia superba at South Georgia
1 January, 2000
The Mana Pools sedimentary basin lies within the Zambezi mobile belt in northern Zimbabwe. New and preexisting magnetotelluric data and the available seismic reflection data are used to constrain the…Read more on A magnetotelluric model of the Mana Pools basin, northern Zimbabwe
1 January, 2000 by Roger Worland, William Block
Hydromedion sparsutum is a locally abundant herbivorous beetle on the sub-Antarctic island of South Georgia, often living in close association with the tussock grass Parodiochloa flabellata. Over a 4-day period…1 January, 2000 by David Vaughan
It has been suggested that as much as 90% of the discharge from the Antarctic Ice Sheet is drained through a small number of fast-moving ice streams and outlet glaciers…Read more on Widespread complex flow in the interior of the Antarctic Ice Sheet
1 January, 2000
Phosphorus is scarce in Beacon Sandstone of the McMurdo Dry Valleys, Antarctica, and any input from precipitation is minimal. In endolithic microbial communities recycling of P by the action of…Read more on Phosphatase activities of endolithic communities in rocks of the Antarctic Dry Valleys
1 January, 2000
The phosphomonoesterase activity of a microbialcommunity dominated by Chroococcidiopsis in arock sample from the Antarctic dry desert was comparedwith that of a non-axenic culture of thecyanobacterium isolated from the same…1 January, 2000
We report low temperature gradients (from 60% to 12% of geothermal), and extrapolated temperatures offset from modern bottom water temperatures, in sediments from the central Scotia Sea. We examine possible…1 January, 2000
Tape recordings of two types of vocalisations were used to assess burrow occupancy by white-chinned petrels (Procellaria aequinoctialis) at South Georgia. Birds responded to the rattle call on 74% of…1 January, 2000
The white-chinned petrel (Procellaria aequinoctialis) is an abundant, widespread petrel breeding in tussock grassland at sub-Antarctic islands. Over the last decade it has been killed in large numbers in temperate…1 January, 2000
The foraging range and principal feeding areas of White-chinned Petrels breeding at South Georgia were determined using satellite telemetry. Foraging trips during incubation lasted 12–15 days and covered 3000–8000 km…1 January, 2000 by William Block
Specimens of six enchytraeid species from a wide range of terrestrial habitats were cooled to –25oC and rewarmed at 1oC min-1 and their cryobiological features measured by DSC. All were…Read more on DSC studies of freezing in terrestrial enchytraeids (Annelida: Oligochaeta)
1 January, 2000
The absolute gut evacuation rate (GER) (g day−1) of Harpagifer antarcticus increased with increasing ration mass, fish mass only influenced the absolute GER at a daily ration level of 0·3%…1 January, 2000
This study tests the hypothesis that an endothermic homeotherm should minimise heat flux in cold polar waters by minimising skin temperature. Temperature variability was measured at the surface of the…Read more on Skin temperatures during free-ranging swimming and diving in Antarctic fur seals
1 January, 2000
1. The study tested the hypothesis that the occurrence of pregnancy in mammals that are capital breeders will be most closely related to state variables that are indices of food…Read more on State-dependent fertility in pinnipeds: contrasting capital and income breeders
1 January, 2000 by Eugene Murphy, Philip Trathan
Ocean physics is a key aspect of the operation of island ecosystems, yet the hydrodynamics is sometimes poorly understood. A high-resolution oceanographic survey to the north of South Georgia identified…1 January, 2000 by Jonathan Watkins
Much of the distribution range of Antarctic krill, Euphausia superba, is covered by permanent or seasonal sea ice. Sea ice extent has been implicated as a major factor affecting reproductive…Read more on Effects of sea ice cover on the swarming behaviour of Antarctic krill,Euphausia superba
1 January, 2000
On Bird Island, South Georgia, albatrosses (n = 140), penguins (n = 100), and fur seals (n = 206) were sampled for Campylobacter jejuni. C. jejuni subsp. jejuni was recovered…1 January, 2000
1 The population density, diversity and productivity of the microbial plankton in an oligotrophic maritime Antarctic lake were studied for a 15-month period between December 1994 and February 1996. 2…Read more on Temporal plankton dynamics in an oligotrophic maritime Antarctic lake
1 January, 2000
Cetricycas antarcticus gen. et sp. nov. occurs in the Late Coniacian to Campanian Lachman Crags Member of the Santa Marta Formation, Marambio Group, James Ross Island, Antarctica. The petrified trunk…Read more on A petrified cycad trunk from the Late Cretaceous of the Larsen Basin, Antarctica
1 January, 2000
A macroflora from John Peaks, Powell Island, contains Sagenopteris nilssoniana, Cladophlebis oblonga, Brachyphyllum sp., Elatocladus confertus, and Sphenopteris sp. The macroflora is best correlated with the Botany Bay Group flora,…1 January, 2000
Publication of the Composite gazetteer of Antarctica by the SCAR Working Group on Geodesy and Geographic Information is a major milestone in the evolution of Antarctic toponymy. It has taken…1 January, 2000 by Gareth Chisham, Michael Pinnock
Poleward‐moving line‐of‐sight velocity “flow bursts” have been observed in the cusp by two southern hemisphere SuperDARN HF radars with overlapping fields‐of‐view. This has allowed the estimation of unambiguous two‐dimensional velocity…1 January, 2000 by Gareth Chisham, Michael Pinnock
We present data from conjugate SuperDARN radars describing the high-latitude ionosphere's response to changes in the direction of IMF By during a period of steady IMF Bz southward and Bx…1 January, 2000 by Andrew Clarke
1. We have examined large-scale geographical patterns in species richness for continental shelf bryozoan assemblages in the North Atlantic. Bryozoans are common and often abundant benthic organisms, but they have…1 January, 2000
As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of ∼106 km2 and total as much as…Read more on The state and future of Mars polar science and exploration
1 January, 2000 by Mark Clilverd
Unusually low whistler mode group delay times are observed by VLF Doppler receivers at both Faraday, Antarctica, and Dunedin, New Zealand, following magnetic storms. These are typically caused by plasmaspheric…1 January, 2000 by Michael Pinnock
The antiparallel merging hypothesis states that reconnection takes place on the dayside magnetopause where the solar and geomagnetic fields are oppositely directed. With this criterion, we have mapped the predicted…Read more on The ionospheric footprint of antiparallel merging regions on the dayside magnetopause
1 January, 2000
We aim to identify the important steps in the evolution of the ecosystem approach to management under the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR). The first…1 January, 2000 by Peter Convey
The South Sandwich Islands are an isolated maritime Antarctic volcanic island arc 550-600km south-east of South Georgia. The terrestrial biology of the islands, with emphasis on the unique habitats associated…Read more on The terrestrial micro-arthropod fauna of the South Sandwich Islands
1 January, 2000 by Dominic Hodgson, Helen Peat, Peter Convey
Aim To carry out as comprehensive a survey as practicable of the flora (higher plants, mosses, liverworts, lichens, basidiomycete fungi and diatoms) of the isolated, volcanically active, South Sandwich Islands…1 January, 2000 by Helen Peat, Peter Convey
This paper documents the previously undescribed terrestrial fauna (mites, nematodes, tardigrades) and flora (liverworts, mosses and lichens) of Marion Nunataks, Charcot Island (69°45'S 075°15'W). Species diversity in all groups is…1 January, 2000 by Roger Worland, Peter Convey
In studies of three common, freezing susceptible, Antarctic microarthropods, the springtail Cryptopygus antarcticus and the mites Alaskozetes antarcticus and Halozetes belgicae, we report (i) the consequences on cold tolerance of…Read more on Refining the risk of freezing mortality for Antarctic terrestrial microarthropods
1 January, 2000 by Roger Worland, Peter Convey
Free-living microbivorous nematodes become numerically dominant in Antarctic terrestrial faunas as environmental conditions become more severe, while also reaching very high levels of abundance in moist, vegetated habitats. Nematodes have…Read more on Survival of freezing by free-living Antarctic soil nematodes
1 January, 2000 by Alistair Crame
A major new inventory of living marine Bivalvia (Mollusca) is based on 29 regional faunas. These again pick out strong latitudinal and longitudinal gradients in taxonomic diversity, but there are…1 January, 2000 by Alistair Crame
At the present day the Class Bivalvia comprises some 8000 species, sub-divided into approximately 700 genera, 107 families, and 41 superfamilies (Morton, 1996, and references therein). It represents one of…Read more on Intrinsic and extrinsic controls on the diversification of the Bivalvia
1 January, 2000 by Alistair Crame
Bivalves have been fundamental in developing the understanding of large-scale biodiversity patterns in the marine realm. A new study based on 29 regional bivalve faunas indicates that both latitudinal and…Read more on The nature and origin of taxonomic diversity gradients in marine bivalves
1 January, 2000
In a previous study at South Georgia, carnivory was invoked as a cause of high polyunsaturated fatty acid (PUFA) content of Antarctic krill, Euphausia superba. To examine this, krill were…1 January, 2000 by Lloyd Peck
A complete energy balance equation is calculated for the Antarctic octopus Pareledone charcoti at 0°C. Energy used in respiration, growth, and excretion of nitrogenous and faecal waste, was recorded along…Read more on Energy balance and cold adaptation in the octopus Pareledone charcoti
1 January, 2000 by Paul Rodhouse
In the summer of 1995/96, 25 southern elephant seals, Mirounga leonina, were stomach lavaged at Stranger Point, King George Island, South Shetland Islands. Cephalopod remains were present in 72% of…1 January, 2000
Bipolarity, the presence of a species in the high latitudes separated by a gap in distribution across the tropics, is a well-known pattern of global species distribution. But the question…1 January, 2000
Biomolecules, such as the productive and protective pigments of photosynthetic organisms, are good biomarkers in extreme Antarctic deserts as analogues of early Mars. Laser Raman technology at long wavelengths which…1 January, 2000
A review is made of stratigraphical, geochemical and palaeogeographical data from the northern Antarctic Peninsula and the Southern Ocean for Late Mesozoic-Early Cenozoic times. Clay mineral and S/total organic C…1 January, 2000 by Peter Convey, Sandra McInnes, Sandra McInnes
A small collection of samples from terrestrial and fresh-water habitats on Deception Island in the Maritime Antarctic South Shetland archipelago yielded 14 invertebrate taxa, including four species, which are new…1 January, 2000 by Roger Worland, William Block
DSC analysis was performed at three points in the cryopreservation process on encapsulated-dehydrated meristems of Ribes ciliatum. Meristems were excised from shoots pre-treated with either sucrose or glucose, encapsulated in…1 January, 2000
The Raman spectrum of the photoprotective pigmentscytonemin found in cyanobacterial sheaths has been obtained for the first time. Its skeletal structure is extensively conjugated and unique in nature. Detailed molecular…1 January, 2000
Spawning by Antarctic fish is generally considered to be seasonal and restricted to a brief period during the autumn and winter. Arising from this it has been assumed that the…Read more on Inter-annual variation in the gonad cycle of the mackerel icefish
1 January, 2000
Silicified conifer woods are very common in the mid-Cretaceous (LateAlbian, 100 Ma) Triton Point Member of the Neptune Glacier Formation (Fossil Bluff Group), SE AlexanderIsland, Antarctica. These occur as up…1 January, 2000
A method is outlined in which woods produced by deciduous and evergreen coniferopsids may be distinguished from one another on the basis of a quantitative analysis of growth ring anatomy.…1 January, 2000
Growth rings in modern conifer woods were quantitatively analysed to investigate the relationship between leaflongevity and the markedness of the growth ring boundary. Five conifer species exhibiting a wide range…1 January, 2000 by Andrew Clarke
Environmental seasonality is a critical factor in structuring polar marine ecosystems. The extensive data now available on the lipids of Arctic and Antarctic euphausiids show that all species are characterised…Read more on Lipids, trophic relationships, and biodiversity in Arctic and Antarctic krill
1 January, 2000
The precarious condition of the world's fisheries is making ever-greater demands of the scientific assessment of fish stocks. Traditional assessments that rely on commercial catch statistics can have major shortcomings1…1 January, 2000
Interpretation of an airborne magnetic data compilation containing a key, new survey, together with re-tracked satellite gravity data from the WeddellSeaembayment (WSE), West Antarctica, suggests Rift–Rift–Rift triplejunction formation at the…Read more on Relics of a complex triple junction in the Weddell Sea embayment, Antarctica
1 January, 2000
The Oligocene to Quaternary succession encountered in CRP-2/2A is divided into twelve recurrent lithofacies (some of which have been subdivided further), reflecting a range of marine, glacimarine and possibly subglacial…Read more on Facies analysis and sequence stratigraphy of CRP-2/2A, Victoria Land basin, Antarctica
1 January, 2000 by Howard Roscoe
A recently published analysis of slant columns of NO2 observed at twilight at 45°S has identified trends of about 5%/decade between 1980 and 1998. This is twice the trend in…Read more on Possible causes of stratospheric NO2 trends observed at Lauder, New Zealand
1 January, 2000 by Mervyn Freeman
Magnetospheric cavity modes can decay through various loss processes. Energy leakage across the magnetopause is one such process that is commonly neglected. Here we consider what the actual effect of…Read more on Effect of magnetopause leakage on the lifetime of magnetospheric cavity modes
1 January, 2000 by Mervyn Freeman
In this paper we examine the claim that the power law distribution of burst lifetimes in the AE index is evidence that the magnetosphere is a Self‐Organized Critical (SOC) system.…1 January, 2000 by Mervyn Freeman
We calculate the probability density functions P of burst energy e, duration T, and interburst interval τ for a known turbulent system in nature. Bursts in the Earth-Sun component of…