649 research outputs found
3. Wochenbericht CE0913
Vom 26. Juli bis zum 14. August sind Wissenschaftler vom IFM-GEOMAR auf dem irischen Forschungsschiff Celtic Explorer in der Nordsee unterwegs. Die Expedition CE 0913 unter Fahrtleitung von Dr. Peter Linke findet im Rahmen des Projekts „Fluid- und Gasaustritte in der südlichen deutschen Nordsee“ in Zusammenarbeit mit der Christian-Albrechts-Universität zu Kiel, dem Bundesamt für Seeschifffahrt und Hydrographie und Wintershall statt und dient der Auffindung von Fluid- und Gasaustritten. Die Art und Weise des Austritts und die chemische und isotopische Zusammensetzung der austretenden Gase sollen genauer analysiert werden. Dabei kommen der Tiefseeroboter ROV KIEL 6000, Vibrocorers und Landersysteme zum Einsatz.
CELTIC EXPLORER CE 0913: 2. Wochenbericht (10.‐14.08.2009
Dissolved methane pluming mapping using Membrane Inlet Mass-Spectrometry (MIMS) at a blowout site in the North Sea
A blow out site in the North Sea (well 22/4-b, UK EEZ) in a water depth of 83 m, served as a test area to demonstrate MIMS as a powerful tool for the continuous measurement of dissolved methane simultaneously to the partial
pressure of carbon dioxide, nitrogen and oxygen as well as other gases. A pump-CTD arrangement was used to generate a continuous water stream through a 2.5 cm thick tube to the ship laboratory and was analyzed using a membrane inlet quadrupole mass spectrometer (GAM 200, InProcessInstruments). The pump-CTD was further
equipped with calibrated HydroC CH4/CO2 sensors. The MIMS measurements were conducted under fully controlled temperature conditions and were calibrated for CH4, N2, O2, and pCO2. The pump-CTD arrangement was towed along transects across the blow out and dissolved gas concentrations as well as physical water column data were synchronized and geo-referenced. The transects were repeated in three different depth layers, including a bottom layer of � 2 m above the sea floor, 60 m above the sea floor just below the thermocline and a third plane in 10 m water depth. During the tows water samples were taken for later onboard methane analysis and cross-calibration with the MIMS and HydroC data. After data selection under consideration of the tidal regime lateral and vertical plume dimensions of dissolved methane were constructed. Dissolved methane concentrations ranged between background and up to about 18�M. Below the thermocline, which represents an effective barrier for the vertical distribution of dissolved methane, methane distinctively spreads laterally. Only at locations were the gas bubble stream and concurrently advected water from below the thermocline reaches the sea surface enhanced methane emission into the atmosphere took place
Metabolic adaptations of deep-sea benthic foraminifera to seasonally varying food input
ATP content and metabolic activity of benthic foraminifera were determined from deepsea
sediments of the Norwegian-Greenland Sea. Metabolic activity was analysed by measurements of Electron Transport System (ETS] activity and heat production. This, combined with live observations, revealed 2 survival strategies. Ruperlina stabilis, an obligate suspension feeder, is adapted to conditions in which it receives a steady input of particles throughout the year, enabling it to maintain a relatively high ATP content (153 f 23 ng ATP ind.-l) with a reduced ATP turnover rate (0.008 S-'). In
contrast Cribrostomoides subglobosum, Pyrgo rotalaria and Rhabdammina abyssorum undergo large (up to 10-fold) fluctuations in seasonal values of ATP and heat production, but retain a high, relatively constant ATP turnover rate (i.e. seconds). Such a rapid turnover allows these foraminifera to take quick advantage of sudden nutrient inputs; this state of readiness, however, is maintained at the cost of the protoplasm, which benthic foraminifera are apparently capable of metabolizing in times of starvation. C. subglobosum and P rotalaria responded to several sedimentation events with an increase in ETS activ~tys;i ngle cells sometimes showed extremely high ATP values (50- to 100-fold increase), reflecting an individual physiological response to food input to the deep-sea
2. Wochenbericht CE0913
Vom 26. Juli bis zum 14. August sind Wissenschaftler vom IFM-GEOMAR auf dem irischen Forschungsschiff Celtic Explorer in der Nordsee unterwegs. Die Expedition CE 0913 unter Fahrtleitung von Dr. Peter Linke findet im Rahmen des Projekts „Fluid- und Gasaustritte in der südlichen deutschen Nordsee“ in Zusammenarbeit mit der Christian-Albrechts-Universität zu Kiel, dem Bundesamt für Seeschifffahrt und Hydrographie und Wintershall statt und dient der Auffindung von Fluid- und Gasaustritten. Die Art und Weise des Austritts und die chemische und isotopische Zusammensetzung der austretenden Gase sollen genauer analysiert werden. Dabei kommen der Tiefseeroboter ROV KIEL 6000, Vibrocorers und Landersysteme zum Einsatz.
CELTIC EXPLORER CE 0913: 2. Wochenbericht (4.‐10.08.2009
Ruminal and Plasma Responses in Dairy Cows to Drenching or Feeding Glycerol
Four Holstein dairy cows (137 DIM, 60 kg milk/d) were used in a Latin square with 1-wk periods to evaluate the effect of methods of oral delivery of glycerol on ruminal VFA and plasma concentrations of glucose, 6-hydroxybutyrate (BHBA), nonesterified fatty acids (NEFA), and insulin. All cows were fed only grass hay for ad libitum consumption during 12 h before the experiment. At the start of the experiment, time 0, all cows were fed 5 kg of cracked corn. Treatments administered at time 0 were: 1) control (C), no glycerol; 2) fed glycerol (F), 1 kg of glycerol solution (80% glycerol) added to the com; 3) drench glycerol (D), 1 kg of glycerol solution in 1 L of water and delivered as oral drench; and 4) tube delivery of glycerol (T), 1 kg of glycerol solution in 9 L of water and delivered into the rumen via an esophageal tube. Blood samples were collected at -1, -0.5, 0, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 6, 8, 12, and 24 h after administering glycerol. Rumen samples were collected at 0, 2, 4, and 6 h. After administration of glycerol, concentrations of acetate decreased in rumens of cows while propionate and butyrate were increased by glycerol with peak concentrations at 4 h. Concentrations of glucose were increased in plasma of D and T compared with C, reaching peak concentrations at 1.5 and 3 h for D and T, respectively. Glucose response expressed as area under the curve (AUC) over baseline for 6 h was greater for D and T compared with C. Insulin concentrations in plasma were increased for D and T reaching peak concentrations at 1.4 and 1.1 h for D and T respectively. The 6-hAUCfor insulin concentrations were greater for D and T than for F and C. The BHBA was increased in plasma of D, T, and F compared with C, reaching peak concentrations at 2.5, 2.4, and 1.6h for D, T, and F, respectively. These data demonstrate that the ability of glycerol to increase plasma concentrations of glucose and insulin is dependent upon rapid delivery
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