Zirkulation und Ökosysteme im subpolaren und polaren Nordatlantik : 23.5. - 17.9.2006 = Circulation and ecosystems in the subpolar and polar North Atlantic

Die zweite Reise des FS MARIA S. MERIAN setzt sich aus physikalisch-ozeanographischen und biologischen Programmen zusammen. Der erste Fahrtabschnitt (Leitung Lherminier) führt ein französisches Langzeitprogramm zur Erfassung der atlantischen Umwälzbewegung (OVIDE) fort, bei dem ein hydrographischer Schnitt mit einem umfangreichen Tracerprogramm zwischen Portugal und dem südlichen Grönland aufgenommen wird. Der zweite Abschnitt (Leitung Meincke) ist ein Beitrag zum Hamburger Sonder-forschungsbereich 512, Teilprojekt „Der Ostgrönlandstrom – Indikator niederfrequenter Veränderlichkeit des Ausstroms aus dem System Arktischer Ozean/Europäisches Nordmeer“ und zum Grundprogramm des Alfred-Wegener-Institutes zum Thema „Langzeit-variabilität von Konvektion und Transporten in der Grönlandsee“. Auf dem dritten Abschnitt (Leitung Freiwald) werden neben einer polarforschungshistorischen Studie auf Spitsbergen biosedimentäre Systeme polarer Karbonatvorkommen auf den Schelfen Svalbards im Zusammenhang mit rezenter Klimavariabilität analysiert. Im letzten Abschnitt (Leitung Schauer) werden Langzeitmessungen zum Wassermassenaustausch zwischen Nordatlantik und dem Nordpolarmeer durch die Framstraße und zur Ökologie der polaren Tiefsee fortgeführt. MSM02/1 Im Rahmen eines 2002 begonnenen Langzeitprogramms OVIDE zur Erfassung der atlantischen Umwälzbewegung wird alle 2 Jahre ein hydrographischer Schnitt zwischen Portugal und dem südlichen Grönland aufgenommen. Der Schnitt besteht aus 95 CTD-Stationen und einem umfangreichen Tracer-Programm Begleitet werden die Messungen durch direkte Strömungsmessungen mit ADCPs, - einem im Schiff verankerten sowie einem mit der Rosette gefierten Gerät. Das Programm ist Teil des französischen Programms PNEDC und des inter-nationalen Programms CLIVAR. MSM02/2 Der Fahrtabschnitt MSM02 dient der Fortführung von zwei längerfristigen physikalisch-ozeanographischen Beobachtungsprogrammen der Universität Hamburg und des Alfred-Wegener-Institutes für Polar- und Meeresforschung. Mit Hilfe von in situ Messungen und realitätsnaher Model-lierung soll die saisonale bis zwischenjährliche Veränderlichkeit der Wassermassenzusammensetzung und –transporte sowohl des oberflächennahen und tiefen Ostgrönlandstromes als auch des Grönlandsee-Wirbels untersucht werden. Sie liefern die Daten zur Rolle der Prozesse im Europäischen Nordmeer, die den Eintrag von oberflächennahem Süßwasser und tiefen Overflows in den Nordatlantischen Ozean kontrollieren und damit die für das europäische Klima wichtige atlantische thermohaline Umwälzzirkulation steuern. MSM02/3 Die wissenschaftliche Zielsetzung der Reise MSM02/3 widmet sich der postglazialen Entwicklung benthischer Lebensgemeinschaften auf den Schelfen um Spitzbergen. Die Integration geologischer, biologischer, meeres-chemischer und ozeanographischer Fragestellungen ist durch die Expertise der Fahrtteilnehmer gesichert. Zusätzlich wird das Schicksal der gescheiterten Deutschen Arktis Expedition und ihrer Rettungsexpedition in den Jahren 1912 und 1913 erforscht und ein wichtiges, wenngleich tragisches Kapitel in der deutschen Polarforschung geschlossen. MSM02/4 Das Programm dient ozeanographischen und biologischen Langzeitstudien in der Framstraße. Im Rahmen des EU-geförderten Programms „DAMOCLES“ wird der ozeanische Austausch zwischen dem Nordatlantik und dem Nord-polarmeer bestimmt. Dazu wird seit 1997 auf 79°N ein Verankerungsarray betrieben, das jährlich ausgetauscht wird. Um die räumlichen Skalen besser aufzulösen, werden parallel dazu CTD-Messungen durchgeführt. Über den gleichen Zeitraum währen multidisziplinäre Untersuchungen im Bereich der Tiefsee-Langzeitstation AWI-„Hausgarten“. Neben einem zentralen Experimentierfeld in 2500 m Wassertiefe werden Stationen entlang zweier Transekte in 1000 - 5500 m Wassertiefe aufgesucht, um in biologischen, geochemischen und sedimentologischen Untersuchungen saisonale und mehrjährige Veränderungen identifizieren zu können. Dabei werden neben schiffsgebundenen Proben-nahmegeräten Lander und Verankerungen eingesetzt. Im Rahmen des DFG-Projekts “Biodiversity and ecology of deepsea copepods in polar seas – speciation processes and ecological niches in the homogeneous environment of the pelagic realm” werden die Biodiversität und die Ernährungsökologie dominanter Cope-podenarten der arktischen Tiefsee untersucht.The second cruise of RV MARIA S. MERIAN serves long-term studies of the variability of physical and biological systems of the North Atlantic. The first leg (chief scientist: Lherminier) aims at continuation of a French long-term observation of the North-Atlantic circulation and meridional overturning (OVIDE). It repeats a hydrographic section including a comprehensive tracer programme between Portugal and southern Greenland and exchanges moorings array. The second leg (chief scientist: Meincke) is a contribution to the Hamburg Special Research programme 512, work package ”The east Greenland Current - indicator of low frequency variability of the outflow from the system Arctic Ocean/Nordic Seas” and to the research topic “Convection and transports in the Greenland Sea” of the Alfred Wegener Institute. During the third leg (chief scientist: Freiwald) biosedimentary systems of polar carbon deposits will be investigated with respect to recent climate variability. This will be combined with a study of polar research history on Spitsbergen. The last leg (chief scientist: Schauer) addresses the interannual variability of water mass exchange between North Atlantic and Arctic Ocean through Fram Strait and of the ecology of the polar deep sea. MSM02/1 The OVIDE survey of 2006 is the third of this kind after 2002 and 2004. The core of the project is a hydrographic line crossing the North Atlantic from Greenland to Portugal, measuring tracers and anthropogenic carbon in addition to temperature, salinity and currents at full depth stations every 30 nm at most. The OVIDE hydrographic line is proposed within the framework of CLIVAR and CARBOCEAN (section A25). This project is part of a joint proposal to the PNEDC (a French programme which supports climate research) in collaboration with the SURATLANTE (G. Reverdin). It is also related to the ARGO programme. MSM02/2 The cruise leg MSM02/2 continues ongoing physical oceanographic field measurements carried out by the University of Hamburg and by the Alfred Wegener Institute for Polar and Marine Research. The programme is aimed at measuring and modelling the seasonal to interannual variability of the watermass composition and the transports within the Eastgreenland Current and of the convective activity in the Greenland Sea gyre. We will quantify those processes of the Nordic Seas which provide the Arctic input of freshwater and dense overflow to the North Atlantic and thereby control the Atlantic thermohaline overturning circulation. MSM02/3 The major objective of MSM02/3 is to improve our understanding of the post-glacial evolution of benthic communities on the shelves around Svalbard. The integration of geology, biology, marine chemistry and oceanography is reflected in the expertise of the scientific crew. In addition, the investigation of the fate of the Deutsche Arktis Expedition and the failed rescue expedition in the suceeding year will close an important chapter of Germany’s polar history. MSM02/4 This leg serves to investigate the long-term variability of oceanic fluxes through Fram Strait and of marine polar ecosystems. In the framework of the EU-funded programme DAMOCLES the oceanic exchange between the North Atlantic and the Arctic Ocean will be determined. To that end, since 1997 a mooring array has been maintained at 79°N that is exchanged each year. Along the line, a CTD survey provides temperature, salinity and velocity at a high spatial resolution. The multidisciplinary study of polar deep-sea ecosystems in the AWI-“Hausgarten” lasts for a similar time period. Here, stations between 1000 and 5500 m water depth are sampled each year for biological, geochemical and sedimentological parameters in order to identify interannual changes. Lander and moorings allow seasonal resolution. The biodiversity and feeding strategy of dominant polar deep-sea copepods is studied in the framework of the national project “Biodiversity and ecology of deep-sea copepods in polar seas – speciation processes and ecological niches in the homogeneous environment of the pelagic realm

Adopting Quality Criteria for Websites Providing Medical Information About Rare Diseases

BACKGROUND: The European Union considers diseases to be rare when they affect less than 5 in 10,000 people. It is estimated that there are between 5000 and 8000 different rare diseases. Consistent with this diversity, the quality of information available on the Web varies considerably. Thus, quality criteria for websites about rare diseases are needed. OBJECTIVE: The objective of this study was to generate a catalog of quality criteria suitable for rare diseases. METHODS: First, relevant certificates and quality recommendations for health information websites were identified through a comprehensive Web search. Second, all considered quality criteria of each certification program and catalog were examined, extracted into an overview table, and analyzed by thematic content. Finally, an interdisciplinary expert group verified the relevant quality criteria. RESULTS: We identified 9 quality certificates and criteria catalogs for health information websites with 304 single criteria items. Through this, we aggregated 163 various quality criteria, each assigned to one of the following categories: thematic, technical, service, content, and legal. Finally, a consensus about 13 quality criteria for websites offering medical information on rare diseases was determined. Of these categories, 4 (data protection concept, imprint, creation and updating date, and possibility to contact the website provider) were identified as being the most important for publishing medical information about rare diseases. CONCLUSIONS: The large number of different quality criteria appearing within a relatively small number of criteria catalogs shows that the opinion of what is important in the quality of health information differs. In addition, to define useful quality criteria for websites about rare diseases, which are an essential source of information for many patients, a trade-off is necessary between the high standard of quality criteria for health information websites in general and the limited provision of information about some rare diseases. Finally, transparently presented quality assessments can help people to find reliable information and to assess its quality

Adopting Quality Criteria for Websites Providing Medical Information About Rare Diseases

BACKGROUND: The European Union considers diseases to be rare when they affect less than 5 in 10,000 people. It is estimated that there are between 5000 and 8000 different rare diseases. Consistent with this diversity, the quality of information available on the Web varies considerably. Thus, quality criteria for websites about rare diseases are needed. OBJECTIVE: The objective of this study was to generate a catalog of quality criteria suitable for rare diseases. METHODS: First, relevant certificates and quality recommendations for health information websites were identified through a comprehensive Web search. Second, all considered quality criteria of each certification program and catalog were examined, extracted into an overview table, and analyzed by thematic content. Finally, an interdisciplinary expert group verified the relevant quality criteria. RESULTS: We identified 9 quality certificates and criteria catalogs for health information websites with 304 single criteria items. Through this, we aggregated 163 various quality criteria, each assigned to one of the following categories: thematic, technical, service, content, and legal. Finally, a consensus about 13 quality criteria for websites offering medical information on rare diseases was determined. Of these categories, 4 (data protection concept, imprint, creation and updating date, and possibility to contact the website provider) were identified as being the most important for publishing medical information about rare diseases. CONCLUSIONS: The large number of different quality criteria appearing within a relatively small number of criteria catalogs shows that the opinion of what is important in the quality of health information differs. In addition, to define useful quality criteria for websites about rare diseases, which are an essential source of information for many patients, a trade-off is necessary between the high standard of quality criteria for health information websites in general and the limited provision of information about some rare diseases. Finally, transparently presented quality assessments can help people to find reliable information and to assess its quality

A water column study of methane around gas flares located at the West Spitsbergen continental margin

In the Arctic Seas, the West Spitsbergen continental margin represents a prominent methane seep area. In this area, free gas formation and gas ebullition as a consequence of hydrate dissociation due to global warming are currently under debate. Recent studies revealed shallow gas accumulation and ebullition of methane into the water column at more than 250 sites in an area of 665 km2. We conducted a detailed study of a subregion of this area, which covers an active gas ebullition area of 175 km2 characterized by 10 gas flares reaching from the seafloor at~245 m up to 50 m water depth to identify the fate of the released gas due to dissolution of methane from gas bubbles and subsequent mixing, transport and microbial oxidation. The oceanographic data indicated a salinity-controlled pycnocline situated ~20 m above the seafloor. A high resolution sampling program at the pycnocline at the active gas ebullition flare area revealed that the methane concentration gradient is strongly controlled by the pycnocline. While high methane concentrations of up to 524 nmol L−1 were measured below the pycnocline, low methane concentrations of less than 20 nmol L−1 were observed in the water column above. Variations in the δ13CCH4 values point to a 13C depleted methane source (~−60‰ VPDB) being mainly mixed with a background values of the ambient water (~−37.5‰ VPDB). A gas bubble dissolution model indicates that ~80% of the methane released from gas bubbles into the ambient water takes place below the pycnocline. This dissolved methane will be laterally transported with the current northwards and most likely microbially oxidized in between 50 and 100 days, since microbial CH4 oxidation rates of 0.78 nmol d−1 were measured. Above the pycnocline, methane concentrations decrease to local background concentration of ~10 nmol L−1. Our results suggest that the methane dissolved from gas bubbles is efficiently trapped below the pycnocline and thus limits the methane concentration in surface water and the air–sea exchange during summer stratification. During winter the lateral stratification breaks down and fractions of the bottom water enriched in methane may be vertically mixed and thus be potentially an additional source for atmospheric methane

Metabolite Profiling Uncovers Plasmid-Induced Cobalt Limitation under Methylotrophic Growth Conditions

BACKGROUND:The introduction and maintenance of plasmids in cells is often associated with a reduction of growth rate. The reason for this growth reduction is unclear in many cases. METHODOLOGY/PRINCIPAL FINDINGS:We observed a surprisingly large reduction in growth rate of about 50% of Methylobacterium extorquens AM1 during methylotrophic growth in the presence of a plasmid, pCM80 expressing the tetA gene, relative to the wild-type. A less pronounced growth delay during growth under non-methylotrophic growth conditions was observed; this suggested an inhibition of one-carbon metabolism rather than a general growth inhibition or metabolic burden. Metabolome analyses revealed an increase in pool sizes of ethylmalonyl-CoA and methylmalonyl-CoA of more than 6- and 35-fold, respectively, relative to wild type, suggesting a strongly reduced conversion of these central intermediates, which are essential for glyoxylate regeneration in this model methylotroph. Similar results were found for M. extorquens AM1 pCM160 which confers kanamycin resistance. These intermediates of the ethylmalonyl-CoA pathway have in common their conversion by coenzyme B(12)-dependent mutases, which have cobalt as a central ligand. The one-carbon metabolism-related growth delay was restored by providing higher cobalt concentrations, by heterologous expression of isocitrate lyase as an alternative path for glyoxylate regeneration, or by identification and overproduction of proteins involved in cobalt import. CONCLUSIONS/SIGNIFICANCE:This study demonstrates that the introduction of the plasmids leads to an apparent inhibition of the cobalt-dependent enzymes of the ethylmalonyl-CoA pathway. Possible explanations are presented and point to a limited cobalt concentration in the cell as a consequence of the antibiotic stress