Search results for "Underwater"
showing 10 items of 1058 documents
Teleradiologie nach Röntgenverordnung - beispielhafte Anwendung der Open-Source-Software SecTelMed
2005
Purpose: Establishing a teleradiology connection according to the Rontgenverordnung (RoV) between a peripheral hospital and a university clinic will contribute to improve the radiological emergency treatment on weekends, holidays and at night. It will also better the medical care for patients and help to lower the costs. Materials and Methods: By using the open source software SecTelMed, the radiological picture is transferred via an internet-linked SSH communication server. The integration of the teleradiological data transfer into the actual workflow is attained by using the already existing PACS infrastructure. While its installation is still under construction, it is actually employed f…
Soil fungal community composition does not alter along a latitudinal gradient through the maritime and sub-Antarctic
2012
We investigated the relationships between fungal community composition, latitude and a range of physicochemical parameters in 58 soils sampled from a 2370 km latitudinal gradient between South Georgia (54 S, 38 W) in the sub-Antarctic and Mars Oasis (72 S, 68 W) on Alexander Island in the southern maritime Antarctic. Our study, which is based on approximately ten times the number of samples used in previous similar studies, indicates that latitude and its associated environmental parameters are not related to fungal community composition. Significant changes in the composition of soil fungal communities were observed in relation to gradients of the ratio of total organic carbon to nitrogen,…
Revisiting the disappearance of terrestrial dissolved organic matter in the ocean: a <i>δ</i><sup>13&lt…
2014
Abstract. Organic carbon (OC) depleted in 13C is a widely used tracer for terrestrial organic matter (OM) in aquatic systems. Photochemical reactions can, however, change δ13C of dissolved organic carbon (DOC) when chromophoric, aromatic-rich terrestrial OC is selectively mineralized. We assessed the robustness of the δ13C signature of DOC (δ13CDOC) as a tracer for terrestrial OM by estimating its change during the photobleaching of chromophoric DOM (CDOM) from 10 large rivers. These rivers cumulatively account for approximately one-third of the world's freshwater discharge to the global ocean. Photobleaching of CDOM by simulated solar radiation was associated with the photochemical mineral…
Role of terrestrial carbon in aquatic UV exposure and photoprotective pigmentation of meiofauna in subarctic lakes
2015
Summary Aquatic organisms are adversely influenced by ultraviolet radiation (UV) and utilise photoprotective strategies, including pigmentation. We examined UV-protective melanin pigmentation of aquatic meiofauna (Cladocera) in relation to the UV exposure across 25 tree line lakes in Finland to address the potential effects of increased UV and altered input of UV-screening terrestrial dissolved organic carbon (DOC) on aquatic organisms. Bio-optical parameters, including concentration of DOC, the coloured dissolved organic matter (CDOM) fraction, a suite of carbon quality indices and chlorophyll a, were analysed from lake water, and their role in controlling underwater UV environment (measur…
Nitrogen isotope evidence for stepwise oxygenation of the ocean during the Great Oxidation Event
2019
24 pages; International audience; The Earth’s oxygenation represents one of the most important environmental drivers of life’s evolution, with the first rise, known as ‘the Great Oxidation Event’ (GOE), corresponding to unpreceded accumulation of atmospheric O2, changes in the flux of marine nutrients and possibly global glaciations. However, the detailed evolution of the GOE is still debated, as for instance the accumulation trends of oceanic versus atmospheric oxygen and the nature of biogeochemical responses to oxygenation. Here, we combine organic carbon and bulk nitrogen isotope compositions with major element concentrations and iron speciation data of sedimentary rocks recovered from …
Suspended particulate matter fluxes along with their associated metals, organic matter and carbonates in a coastal Mediterranean area affected by min…
2016
International audience; A study of suspended particulate matter (SPM) fluxes along with their associated metals, organic matter and carbonates, was conducted off the Mejerda River outlet in May 2011 and in March and July 2012 at depths of 10, 20 and 40 m using sediment traps. SPM fluxes are more significant near the Mejerda outlet, especially in winter, but dissipate further offshore. Normalization reveals that the Mejerda is a major source of Pb, Zn, Cd, Cu, Ni, and Co, all of which are the result of human activities. In contrast, Fe, Mn and N are of authigenic origin. The enrichment factor shows that Pb, Zn and especially Cd are the most highly polluting metals off the Mejerda outlet. Thi…
Dynamics of sediments along with their core properties in the Monastir-Bekalta coastline (Tunisia, Central Mediterranean)
2017
International audience; The authors report on two campaigns of high-resolution samplings along the shores of Monastir Bay in Tunisia: the first being a study of sediment dynamics, grain size and mineral composition in surface sediment, and the second, eight months later, using four sediment cores to study grain-size distribution in bottom sediments. Particle size analysis of superficial sediment shows that the sand in shallow depths is characterized by S-shaped curves, indicating a certain degree of agitation, possible transport by rip currents near the bottom and hyperbolic curves illustrating heterogeneity of sand stock. The sediments settle in a relatively calm environment. Along the bay…
Submarine deposits from pumiceous pyroclastic density currents traveling over water: An outstanding example from offshore Montserrat (IODP 340)
2017
© 2016. Geological Society of America. All right reserved. Pyroclastic density currents have been observed to both enter the sea, and to travel over water for tens of kilometers. Here, we identified a 1.2-m-thick, stratified pumice lapilli-ash cored at Site U1396 offshore Montserrat (Integrated Ocean Drilling Program [IODP] Expedition 340) as being the first deposit to provide evidence that it was formed by submarine deposition from pumice-rich pyroclastic density currents that traveled above the water surface. The age of the submarine deposit is ca. 4 Ma, and its magma source is similar to those for much younger Soufrière Hills deposits, indicating that the island experienced large-magnitu…
Sea-level changes during the last 41,000 years in the outer shelf of the southern Tyrrhenian Sea: Evidence from benthic foraminifera and seismostrati…
2011
Abstract An integrated high resolution study based both on a seismostratigraphic approach and on a sedimentary core (VIB 10), collected in the outer shelf (127 m depth) from the southern Tyrrhenian Sea (Gulf of Termini, Sicily), provides new data about climatic, eustatic and paleoenvironmental changes during the last ∼41,000 years. The results based on the interpretation of a seismic profile, on benthic foraminifera assemblages and on δ18O records, allowed recognition of two drastic sea-level falls during the Last Glacial Maximum (LGM) and the Younger Dryas (YD). The short deglacial event, between LGM and YD, known as Bolling/Allerod, played an important role in the sea-level rise that prod…
Attuning to a changing ocean
2020
The ocean is a lifeline for human existence, but current practices risk severely undermining ocean sustainability. Present and future social−ecological challenges necessitate the maintenance and development of knowledge and action by stimulating collaboration among scientists and between science, policy, and practice. Here we explore not only how such collaborations have developed in the Nordic countries and adjacent seas but also how knowledge from these regions contributes to an understanding of how to obtain a sustainable ocean. Our collective experience may be summarized in three points: 1) In the absence of long-term observations, decision-making is subject to high risk arising from na…