33,027 research outputs found
The Role of Evidence in Establishing Trust in Repositories
No full textThis article arises from work by the Digital Curation Centre (DCC) Working Group examining mechanisms to roll out audit and certification services for digital repositories in the United Kingdom. Our attempt to develop a program for applying audit and certification processes and tools took as its starting point the RLG-NARA Audit Checklist for Certifying Digital Repositories. Our intention was to appraise critically the checklist and conceive a means of applying its mechanics within a diverse range of repository environments. We were struck by the realization that while a great deal of effort has been invested in determining the characteristics of a 'trusted digital repository', far less effort has concentrated on the ways in which the presence of the attributes can be demonstrated and their qualities measured. With this in mind we sought to explore the role of evidence within the certification process, and to identify examples of the types of evidence (e.g., documentary, observational, and testimonial) that might be desirable during the course of a repository audit.
LIPID ENVIRONMENTAL BIOMARKERS IN PLANKTON OF THE ROSS SEA (ANTARCTICA)
No full textThe Antarctic zooplankton is adapted to low temperatures and the shortness of the primary production period. The lipid characterisation in these animals can increase the knowledge of biological and biochemical adaptation and of the transfer through trophic levels of molecules considered as environmental biomarkers. Therefore in the present study were analysed hydrocarbons, sterols, fatty acids (FAMEs) and waxes from the total lipid extracts of three zooplankton samples (1mm mesh Plankton Hamburg Net) collected on December 1997 in the stations PHN20, 22 and 30 in the "Continental Slope" sector of the Ross Sea
Oceanography of the Edisto inlet (Western Ross Sea): First results from the XXXVIII Italian Antarctic expedition
No full textLaminated diatomaceous deposits have been documented in a few Antarctic regions, including the Antarctic Peninsula and the Ross Sea. In general, very high sedimentation rates can overwhelm limited bioturbation and thus foster the preservation of varves, for example in some glacio-marine settings. Laminated sediments, collected in the Edisto Inlet, western Ross Sea, showed well-defined dark and light laminae on mm- to cm-scale. Dark laminae contained relatively high concentrations of a biomarker of fast ice IPSO25, whereas, low IPSO25 concentrations characterized light laminae and the diatom Corethron pennatum became the dominant species. Based on these assumptions, fast ice dynamics were reconstructed over the last 2.6 ka for the western Ross Sea. Nevertheless, the absence of rigorous varve validation leaves uncertain the paleoclimatic and paleoceanographic interpretation of these laminated sediments. The project PNRA_LASAGNE (Laminated sediments in the magnificent Edisto Inlet (Victoria Land): What processes control their deposition and preservation?) proposes a multidisciplinary study integrating fast-ice, water column and surface sediment characteristics, supported by biological data collected in situ and time-series of satellite images of sea-ice, to gain information on factors influencing the formation and preservation of laminated sediment in Edisto Inlet. It aims at providing new insights into the sub-seasonal formation of laminated sediments providing a backbone for the interpretation of paleoclimate sediment archives. Here, we show the preliminary results obtained from an extensive dataset collected in Edisto Inlet during the XXXVIII Italian PNRA expedition conducted onboard the I/B Laura Bassi in Feb 2023. Data includes CTD vertical profiles with additional parameters (DO, fluorescence, turbidity) spatially distributed within and at the entrance of the bay, which was still partially covered by seasonal sea ice at the time of the cruise. Moreover, vessel mounted (vm) and Lowered (L) ADCPs have been collected along transects and at each CTD station, respectively. The dataset also include time series from an oceanographic mooring between Feb 2022-Feb 2023. The cruise objective was to perform a synoptic survey during austral Antarctic summer to describe the water mass distribution and current dynamics in the bay, which are mainly driven by sea ice formation and melting, and by atmospheric and tidal forcing. To complement physical data, we collected 3 sea ice cores in Nov 2022, and 7 short sediment cores together with water samples during the cruise to have a picture of the phytoplankton and microzooplankton living in the platelet ice in spring and in open water in summer, respectively. Timing and composition of organic debris sinking in the water column are obtained by sediment trap samples.
Early diagenesis has been also taken into account to define how the original signal is preserved in the sedimentary record
The marriage record of Banthum, Joseph F. and Ross, Leonora M
No full textMarriage license for Joseph F. Banthum and Leonora M. Ross. Charles Donovan was the Notary Public
Ocean acidification state in the Ross Sea surface waters: physical and biological forcing
No full textThe Ross Sea is vulnerable to Ocean Acidification (OA) due to its relatively low total alkalinity and because of increased CO2 solubility in cold water. OA induced decreases in the saturation state (Ω) for calcite and aragonite have potentially serious consequences for Antarctic food webs. Throughout the ocean, mesoscale processes (on spatial scales of 10-100 km and temporal ranges from hours to days) have first-order impacts on phytoplankton physiochemical controls and are critical in determining growth patterns and distribution. The circulation of the surface waters in the Ross Sea is affected by the presence of small-scale structures such as eddies, fronts and filaments, which can penetrate deep below the surface layer and hence influence the intensity of the bloom by supplying nutrients and trace elements, such as iron. Little is known about the effects of mesoscale structures on the carbonate system , but predicting future surface OA state and estimating future CO2 fluxes on a regional scale require understanding of the mesoscale processes controlling the carbonate system.
To this purpose, water samples were collected in January 2014 in the framework of Ross Sea Mesoscale experiment (RoME) Project to evaluate the physical and biological forcing on the carbonate system at distance between stations of 5-10 km. Remote sensing supported the determination of the sampling strategy and helped positioning each sampling station. Total alkalinity, pH, dissolved oxygen, phytoplankton pigments and composition were investigated in combination with measurements of temperature, salinity and current speed. Total inorganic carbon, sea water CO2 partial pressure and Ω for calcite and aragonite were calculated from the measured total alkalinity and pH. In addition, continuous measurements of atmospheric CO2 concentration were completed. Different mesoscale physical features, such as fronts and eddies were observed in the investigated areas, which influenced the distribution of chemical parameters and of phytoplankton community in terms of biomass concentration (Chl-a) and species composition. The carbonate system properties in surface waters exhibited mesoscale variability with a horizontal length scale of about 10 km. Our results document substantial spatial heterogeneity and complexity in surface water carbonate system properties and the magnitude of the CO2 flux at a horizontal length scale of about 10 km, emphasizing the importance of mesoscale events to regional biogeochemistry. We believe that the resolution of these short length scale distributions provides insight into the biogeochemical dynamics which drive surface and subsurface variability in the Ross Sea
Ocean acidification state in the Ross Sea surface waters: physical and biological forcing.
No full textThe Ross Sea is vulnerable to Ocean Acidification (OA) due to its relatively low total alkalinity and because of increased CO2 solubility in cold water. OA induced decreases in the saturation state (Ω) for calcite and aragonite have potentially serious consequences for Antarctic food webs. Throughout the ocean, mesoscale processes (on spatial scales of 10-100 km and temporal ranges from hours to days) have first-order impacts on phytoplankton physiochemical controls and are critical in determining growth patterns and distribution. The circulation of the surface waters in the Ross Sea is affected by the presence of small-scale structures such as eddies, fronts and filaments, which can penetrate deep below the surface layer and hence influence the intensity of the bloom by supplying nutrients and trace elements, such as iron. Little is known about the effects of mesoscale structures on the carbonate system , but predicting future surface OA state and estimating future CO2 fluxes on a regional scale require understanding of the mesoscale processes controlling the carbonate system.
To this purpose, water samples were collected in January 2014 in the framework of Ross Sea Mesoscale experiment (RoME) Project to evaluate the physical and biological forcing on the carbonate system at distance between stations of 5-10 km. Remote sensing supported the determination of the sampling strategy and helped positioning each sampling station. Total alkalinity, pH, dissolved oxygen, phytoplankton pigments and composition were investigated in combination with measurements of temperature, salinity and current speed. Total inorganic carbon, sea water CO2 partial pressure and Ω for calcite and aragonite were calculated from the measured total alkalinity and pH. In addition, continuous measurements of atmospheric CO2 concentration were completed. Different mesoscale physical features, such as fronts and eddies were observed in the investigated areas, which influenced the distribution of chemical parameters and of phytoplankton community in terms of biomass concentration (Chl-a) and species composition. The carbonate system properties in surface waters exhibited mesoscale variability with a horizontal length scale of about 10 km. Our results document substantial spatial heterogeneity and complexity in surface water carbonate system properties and the magnitude of the CO2 flux at a horizontal length scale of about 10 km, emphasizing the importance of mesoscale events to regional biogeochemistry. We believe that the resolution of these short length scale distributions provides insight into the biogeochemical dynamics which drive surface and subsurface variability in the Ross Sea
Age, geographical distribution and taphonomy of an unusual occurrence of mummified crabeater seals on James Ross Island, Antarctica
No full textAn unusually dense collection of some 150 dead crabeater seals (Family Phocidae), in various stages of decay, occurs in the Brandy Bay hinterland, north-western James Ross Island, northern Antarctic Peninsula. Throughout the past 100 years, the presence of shelf ice (no longer present today) and sea ice in Prince Gustav Channel, between James Ross Island and the Antarctic Peninsula, has prevented seals from readily accessing the western side of James Ross Island. However, open water pools, some over one kilometre in diameter, remain accessible throughout the winter months, allowing seals to haul out onto the ice. It is likely that some of these seals may become disorientated as they wander away from the pools and instead head toward Brandy Bay and onto low-lying and snow-covered Abernethy Flats, easily mistaken for sea ice in early winter, where they perish. The large number of variably-decayed animals present suggests that this has probably happened on numerous occasions. However, some of the dead seals also probably perished during a documented mass dying event of crabeater seals in Prince Gustav Channel caused by an unidentified epidemic, possibly phocine distemper virus (PDV), during the spring of 1955
Diatom diversity during two austral summers in the Ross Sea (Antarctica)
No full textPhytoplankton blooms in the Ross Sea generally occur during late spring-early summer, especially in the marginal ice zone, polynya areas and continental shelves. These blooms are generally dominated by many species of diatoms and the haptophyte Phaeocystis antarctica, and are driven by water column dynamics. However, most of the information on diatoms in the Ross Sea regards their ecological and biogeochemical role in Antarctic waters, with few and fragmented data describing the species composition. In order to contribute to the information on diatom diversity in the Ross Sea, data from two oceanographic cruises carried out in austral summers 2014 and 2017, have been analyzed also with respect to their spatial variability. Up to four genera, such as the pennates Fragilariopsis and Pseudo-nitzschia and the centrics Dactyliosolen and Chaetoceros, were mainly observed during the cruises. In both years, pennates dominated at coastal stations in early summer, while centric diatoms dominated in offshore waters particularly at 0 m in mid-summer. The most abundant species was Pseudo-nitzschia subcurvata contrarily to that reported by previous studies where Fragilariopsis curta and F. cylindrus were the most abundant species. Regarding the role of diatoms in the Antarctic food web, changes in species composition should be considered in light of recent studies on the effect of the ongoing climate change in the Ross Sea
Comparative Ross Risk Aversion in the Presence of Mean Dependent Risks
No full textThis paper studies comparative risk aversion between risk averse agents in the presence of a background risk. Although the literature covers this question extensively, our contribution differs from most of the literature in two respects. First, background risk does not need to be additive or multiplicative. Second, the two risks are not necessary mean independent, and may be conditional expectation increasing or decreasing. We show that our order of cross Ross risk aversion is equivalent to the order of partial risk premium, while our index of decreasing cross Ross risk aversion is equivalent to decreasing partial risk premium. These results generalize the comparative risk aversion model developed by Ross (1981) for mean independent risks. Finally, we show that decreasing cross Ross risk aversion gives rise to the utility function family belonging to the class of n-switch utility functions.Comparative cross Ross risk aversion, Dependent background risk, Partial risk premium, Decreasing cross Ross risk aversion, n-switch utility function
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