1,721,136 research outputs found
Nutrient Data from CTD Nisken Bottles from Sonne Expedition SO-245 "UltraPac"
No full textNutrient data from Nisken Bottle samples collected and measured onboard Sonne Expedition SO-245 "UltraPac". Concentrations of dissolved inorganic phosphate (PO43-), nitrite (NO2-), nitrate (NO3-), and silicate (Si) were measured with the QuAAtro39 autoanalyser (Seal Analytical) using the method based on Strickland and Parsons, 1972. OSIL Seawater Low-Nutrient Standards were used as a secondary standard to test primary standard calibrations. Low concentrations of dissolved phosphate (<300 nM) were determined with a long waveguide capillary cell (LWCC) set-up, which included a Traacs 800 pump and autosampler, a World-Precision 100 cm LWCC, an HL 2000 Lamp from Ocean Optics and a STS-VIS Miniatur Spectrophotometer from Ocean Optics. Minimum quantifiable limits were set at 2 times the Minimum Detection Limit given for the method. Oxygen was measured on selected samples by Winkler titration for the purpose of calibrating the CTD O2 sensor. Temperature, Salinity, Sigma-Theta, and Dissolved Oxygen data are included for information and derive originally from: Zielinski, Oliver; Henkel, Rohan; Voß, Daniela; Ferdelman, Timothy G (2018): Physical oceanography during SONNE cruise SO245 (UltraPac).PANGAEA, https://doi.org/10.1594/PANGAEA.89039
Intermediate sulfur oxidation state compounds in the euxinic surface sediments of the Dvurechenskii mud volcano (Black Sea)
No full textThe deep Black Sea is known to be depleted in electron-acceptors for sulfide oxidation. This study on depth distributions of sulfur species (S(II), S(0), View the MathML sourceSn2-, View the MathML sourceS2O32-, View the MathML sourceSO32-, View the MathML sourceSO42-) in the Dvurechenskii mud volcano, a cold seep situated in the permanently anoxic eastern Black Sea basin (Sorokin Trough, 2060 m water depth), showed remarkable concentrations of sulfide oxidation products. Sulfite concentrations of up to 11 μmol L−1, thiosulfate concentrations of up to 22 μmol L−1, zero-valent sulfur concentrations of up to 150 μmol L−1 and up to five polysulfide species were measured in the upper 20 cm of the sediment. Electron-acceptors found to be available in the Dvurechenskii mud volcano (DMV) for the oxidation of hydrogen sulfide to sulfide oxidation intermediates are iron-minerals, and probably also reactive manganese phases. Up to 60 μmol g−1 of reactive iron-minerals and up to 170 μmol L−1 dissolved iron was present in the central summit with the highest fluid upflow and fresh mud outflow. Thus, the source for the oxidative power in the DMV are reactive iron phases extruded with the mud from an ancient source in the deeply buried sediments, leading to the formation of various sulfur intermediates in comparably high concentrations. Another possible source of sulfide oxidation intermediates in DMV sediments could be the formation of zero-valent sulfur by sulfate dependent anaerobic microbial oxidation of methane followed by disproportionation of zero-valent sulfur. Sulfide oxidation intermediates, which are produced by these processes, do not reach thermodynamic equilibrium with rhombic sulfur, especially close to the active center of the DMV due to a short equilibration time. Thus, mud volcano sediments, such as in the DMV, can provide oxidizing niches even in a highly reduced environment like the abyssal part of the Black Sea
Water column raw data (Kongsberg EM 122 entire dataset) of RV SONNE during cruise SO245
No full textWater column raw data using the ship's own Kongsberg EM 122 multibeam echosounder was almost continuously recorded during RV SONNE cruise SO245. Data was recorded on 33 days between 2015-12-23 and 2016-01-25 in the South Pacific Ocean (during transit also crossing the flank of the Leont'ev Seamount). These profiles are part of the corresponding raw dataset (https://doi.org/10.1594/PANGAEA.980702) (which include the .all files). The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM)
Mobilisierung von Schwefel durch grünen Schwefelbakterien : Physiologische und molekulare Untersuchungen an Chlorobaculum parvum DSM 263
No full textGreen sulfur bacteria are photolithotrophs that use inorganic sulfur compounds as electron donors for photosynthesis. Elemental, solid sulfur is one of the electron donors used. Sulfur is produced by green sulfur bacteria during the oxidation of sulfide to sulfate, and during the oxidation of thiosulfate to sulfur and sulfate. Green sulfur bacteria have been known for long, and the genomes of 12 strains have been sequenced. Yet, it is not clear how green sulfur bacteria can access elemental sulfur, which is practically insoluble at the temperatures at which most of them grow. The present work has been done using pure cultures of the mesophilic strain Chlorobaculum parvum DSM 263. By studying the dynamics of inorganic sulfur compounds in growing cultures of Cla. parvum DSM 263, it was shown that the sulfur produced during thiosulfate oxidative disproportionation can be either oxidized immediately to sulfate, or released outside the cells. Extracellular sulfur oxidation needs a dedicated system, which is not synthesised in the presence of thiosulfate. Experiments conducted at low light intensities revealed that thiosulfate is not consumed exclusively via the Sox multienzymatic system, known thus far as the only thiosulfate oxidizing system present in green sulfur bacteria. It is not clear yet if this additional pathway for thiosulfate consumption allows strain DSM 263 to obtain electrons for thiosulfate, or if it is used by bacteria to consume the reducing power that cells might have in excess. Physiological studies conducted on Cla. parvum DSM 263 fed with sulfur furnished evidence that the oxidation of elemental sulfur to sulfate is accompanied by the formation of yet unidentified sulfur compound(s). Similarly to what commented for thiosulfate consumption, these compounds could be intermediates in the oxidation of sulfur to sulfate, or could be side products of sulfur consumption. Essential elements for the utilisation of elemental sulfur were shown to be present in the membranes of Cla. parvum DSM 263. Differential membrane proteomic studies were thus performed on cells of Cla. parvum DSM 263 grown on sulfur or on sulfide. Seven proteins were found to be overexpressed in sulfuric conditions, revealing that bacteria do possess different proteomic equipment for oxidizing the insoluble sulfur rather than the soluble sulfide. Identification of these overexpressed proteins and of their interaction partners will probably help revealing the cellular apparatus of extracellular solid sulfur mobilization
Multibeam bathymetry raw data (Kongsberg EM 122 entire dataset) of RV SONNE during cruise SO245
No full textMultibeam bathymetry raw data using the ship's own Kongsberg EM 122 multibeam echosounder was almost continuously recorded during RV SONNE cruise SO245. Data was recorded on 33 days between 2015-12-23 and 2016-01-26. This dataset contains a transit survey in the South Pacific Ocean (during transit also crossing the flank of the Leont'ev Seamount). The approximate average depth of the entire dataset is around 4400m. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. Ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus SVP files are added to this dataset. Data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be expected due to the lack of proper SVP. Overall, it appears that the data quality is rather good since the gridded hillshade data showed relatively few obstacles. Data can be processed e.g. with the open source software package MB-System (Caress et al. 2024, https://doi.org/10.5281/zenodo.6302801)
Die Schlüsselrolle von Sulfitarten für die Sauerstoffisotopenzusammensetzung in Sulfat: neue Einsichten von einer stabilen Isotopenperspektive
No full textThe oxygen isotope composition of sulfate can be used as archive for microbial and abiotic processes that prevail in the environment as sulfate does not exchange oxygen with the water under most natural conditions. The oxygen isotope composition of ancient sulfate minerals can be used to draw conclusions on the environmental conditions that prevailed in the past. This work investigated especially the influence of sulfite on the oxygen isotope composition of sulfate. Sulfite is often mentioned as final sulfoxy intermediate during the oxidation of reduced sulfur compounds and in contrast to sulfate it exchanges rapidly oxygen with water. The results of this work reveal the importance of sulfite in shaping the oxygen isotope composition of sulfate and how differences in the experimental setup (pH, oxidant) produce highly different values that accommodate for almost the entire range of oxygen isotope compositions of sulfate from natural environments
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Multibeam bathymetry raw data (EM 120 echosounder entire dataset) of RV METEOR during cruise M76/1b
No full textMultibeam bathymetry raw data using the ship's own Kongsberg (Simrad) EM 120 multibeam echosounder was continuously recorded during RV METEOR cruise M76/1b. Data was recorded on 18 days between 2008-04-26 and 2008-05-13. This dataset contains a survey data in the Namibian shelf area towards the continental slope (South Atlantic Ocean). The approximate average depth of the entire dataset is around 2700m. The data are archived at the Federal Maritime and Hydrographic Agency of Germany (Bundesamt für Seeschifffahrt und Hydrographie, BSH) and provided to PANGAEA database for data curation and publication. No ancillary sound velocity profiles (SVP) files from the cruise are archived at the BSH, thus no SVP files are added to this dataset. However, data analysis of the multibeam raw data revealed that SVP has been changed during the survey. This publication is conducted within the efforts of the German Marine Research Alliance in the core area 'Data management and Digitalization' (Deutsche Allianz Meeresforschung, DAM). Data are unprocessed and therefore contains incorrect depth measurements (artifacts) without further processing. Note that refraction errors can be seen already in the data due to the lack of proper SVP. Overall, it appears that the data quality is rather moderate since the gridded hillshade data showed some obstacles. Data can be processed e.g. with the open source software package MB-System (Caress et al. 2024, https://doi.org/10.5281/zenodo.6302801)
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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