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Highlights • BSR position does not match BGHS as predicted based on regional TP conditions. • Use steady state and transient models to determine extent of hydrate stability. • Investigate the influence of topographic focusing on hydrate stability. • Variable thermal properties of sediment impact hydrate stability. The Danube Fan in the western Black Sea shows many features indicating the presence of gas and gas hydrates, including a bottom simulating reflection (BSR), high-amplitude anomalies beneath the BSR and the presence of gas flares at the seafloor. The BSR depth derived from 3D P-cable seismic data of an older slope canyon of the fan (the S2 canyon) suggests that the BSR is not in equilibrium with the present-day topography. The Danube Fan was abandoned ∼7.5 ka, and the S2 canyon was likely incised ∼20 ka, suggesting that the gas hydrate system has had at least 7.5 ka years to equilibrate to the present-day conditions. Here we examine the extent and position of the hydrate stability zone through constructing both steady and transient state models of a 2D profile across the S2 canyon. This was done using inputs from mapping of the 3D P-cable seismic data and geochemical analysis of core samples. Using these models, we investigate the effects of different factors including variable thermal properties of heterogeneous sediments in the vicinity of the canyon and, topographic focusing on the geothermal gradient on the extent of the hydrate stability zone. Our results indicate that both factors have a significant effect and that the hydrate system may actually be in, or approaching equilibrium.

This study explores key features of bromine and iodine metabolism in the filamentous brown alga and genomics model Ectocarpus siliculosus. Both elements are accumulated in Ectocarpus, albeit at much lower concentration factors (2-3 orders of magnitude for iodine, and

Bacteria and archaea import molybdenum and tungsten from the environment in the form of the oxyanions molybdate (MoO4 2−) and tungstate (WO4 2−). These substrates are captured by an external, high-affinity binding protein, and delivered to ATP binding cassette transporters, which move them across the cell membrane. We have recently reported a crystal structure of the molybdate/tungstate binding protein ModA/WtpA from Archaeoglobus fulgidus, which revealed an octahedrally coordinated central metal atom. By contrast, the previously determined structures of three bacterial homologs showed tetracoordinate molybdenum and tungsten atoms in their binding pockets. Until then, coordination numbers above four had only been found for molybdenum/tungsten in metalloenzymes where these metal atoms are part of the catalytic cofactors and coordinated by mostly non-oxygen ligands. We now report a high-resolution structure of A. fulgidus ModA/WtpA, as well as crystal structures of four additional homologs, all bound to tungstate. These crystal structures match X-ray absorption spectroscopy measurements from soluble, tungstate-bound protein, and reveal the details of the distorted octahedral coordination. Our results demonstrate that the distorted octahedral geometry is not an exclusive feature of the A. fulgidus protein, and suggest distinct binding modes of the binding proteins from archaea and bacteria

Diese Broschüre und die gleichnamige Ausstellung befassen sich mit der Entwicklung des Echolots, für das der Kieler Physiker und Unternehmer Alexander Behm im Jahr 1913 das erste Patent erhielt. Erfahren Sie mehr über die Geschichte der Tiefenmessung im Ozean – von den ersten Handloten im alten Ägypten über die dampfgetriebenen Lotmaschinen des 19. Jahrhunderts, der Entwicklung der ozeanischen Tiefenkarten bis hin zur heutigen Vermessung des Meeresbodens mit modernen Fächerecholoten.

18 pages, 9 figures.-- Access to the field data: Bathymetric data from German research cruises (e.g., R/V SONNE SO104, SO244) can be requested through the German Bundesamt für Seeschifffahrt und Hydrographie (BSH; http://www.bsh.de). The bathymetric data collected during R/V Marcus G. Langseth cruise MGL1610 are available from the Rolling Deck to Repository (R2R) Web site (http://www.rvdata.us/). Seismic reflection data from R/V SONNE cruise SO104 are stored at the Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) and can be requested through the Geo‐Seas data portal (http://www.geo‐seas.eu/). Access to processed data: The following data used in this manuscript are available from the PANGAEA data archive (https://doi.pangaea.de/10.1594/PANGAEA.893034): (I) A gridded DEM (100 m) that combines the bathymetric data from R/V SONNE cruises SO104, SO244, and R/V Marcus Langseth cruise MGL1610. (II) A GeoTIFF that contains the backscatter information from the multibeam data collected during R/V SONNE cruise SO244, New multibeam bathymetry allows an unprecedented view of the tectonic regime and its along-strike heterogeneity of the North Chilean marine forearc and the oceanic Nazca Plate between 19 and 22.75°S. Combining bathymetric and backscatter information from the multibeam data with subbottom profiler and published and previously unpublished legacy seismic reflection lines, we derive a tectonic map. The new map reveals a middle and upper slope configuration dominated by pervasive extensional faulting, with some faults outlining a >500-km-long ridge that may represent the remnants of a Jurassic or pre-Jurassic magmatic arc. Lower slope deformation is more variable and includes slope-failures, normal faulting, re-entrant embayments, and NW-SE trending anticlines and synclines. This complex pattern likely results from the combination of subducting lower-plate topography, gravitational forearc collapse, and the accumulation of permanent deformation over multiple earthquake cycles. We find little evidence for widespread fluid seepage despite a highly faulted upper-plate. An explanation could be a lack of fluid sources due to the sediment starved nature of the trench and most of the upper-plate in vicinity of the hyperarid Atacama Desert. Changes in forearc architecture partly correlate to structural variations of the oceanic Nazca Plate, which is dominated by the spreading-related abyssal hill fabric and is regionally overprinted by the Iquique Ridge. The ridge collides with the forearc around 20–21°S. South of the ridge-forearc intersection, bending-related horst-and-grabens result in vertical seafloor offsets of hundreds of meters. To the north, plate-bending is accommodated by reactivation of the paleo-spreading fabric and new horst-and-grabens do not develop, R/V SONNE Cruises SO104 (grant 03G104A) and SO244 (grant 03G0244A) were supported by the German Bundesministerium für Bildung und Forschung (BMBF). A. M. T. thanks the U.S. National Science Foundation (NSF) for support through grant OCE1459368. We also thank the crew and technical staff of the R/V Marcus Langseth, which is funded by the NSF and operated by the Lamont‐Doherty Earth Observatory. […] Jacob Geersen was partly funded by a grant (CP1404) of the Cluster of Excellence 80 “The Future Ocean,” funded within the framework of the Excellence Initiative by Deutsche Forschungsgemeinschaft (DFG) on behalf of the German federal and state governments. C. R. R. was supported by the Grup de Recerca 2014SGR940 de la Generalitat de Catalunya and Spanish Ministry of Science grant PCIN‐2015‐053. E. C.‐R. gratefully acknowledges the support of the Chilean National Science Foundation (FONDECYT) grant 1170009 and the Programa de Investigación Asociativa: ANILLOS DE INVESTIGACIÓN EN CIENCIA Y TECNOLOGÍA, CONICYT, grant ACT172002, project “The interplay between subduction processes and natural disasters in Chile.”

11 pages, 7 figures, Seismic rupture of the shallow plate-boundary can result in large tsunamis with tragic socio-economic consequences, as exemplified by the 2011 Tohoku-Oki earthquake. To better understand the processes involved in shallow earthquake rupture in seismic gaps (where megathrust earthquakes are expected), and investigate the tsunami hazard, it is important to assess whether the region experienced shallow earthquake rupture in the past. However, there are currently no established methods to elucidate whether a margin segment has repeatedly experienced shallow earthquake rupture, with the exception of mechanical studies on subducted fault-rocks. Here we combine new swath bathymetric data, unpublished seismic reflection images, and inter-seismic seismicity to evaluate if the pattern of permanent deformation in the marine forearc of the Northern Chile seismic gap allows inferences on past earthquake behavior. While the tectonic configuration of the middle and upper slope remains similar over hundreds of kilometers along the North Chilean margin, we document permanent extensional deformation of the lower slope localized to the region 20.8°S–22°S. Critical taper analyses, the comparison of permanent deformation to inter-seismic seismicity and plate-coupling models, as well as recent observations from other subduction-zones, including the area that ruptured during the 2011 Tohoku-Oki earthquake, suggest that the normal faults at the lower slope may have resulted from shallow, possibly near-trench breaking earthquake ruptures in the past. In the adjacent margin segments, the 1995 Antofagasta, 2007 Tocopilla, and 2014 Iquique earthquakes were limited to the middle and upper-slope and the terrestrial forearc, and so are upper-plate normal faults. Our findings suggest a seismo-tectonic segmentation of the North Chilean margin that seems to be stable over multiple earthquake cycles. If our interpretations are correct, they indicate a high tsunami hazard posed by the yet un-ruptured southern segment of the seismic gap, Jacob Geersen was funded by a grant (CP1404) of the Cluster of Excellence 80 ‘The Future Ocean’, funded within the framework of the Excellence Initiative by Deutsche Forschungsgemeinschaft (DFG) on behalf of the German federal and state governments. César R. Ranero was supported by the Grup de Recerca 2014SGR940 de la Generalitat de Catalunya. R/V SONNE Cruises SO-104 (Grant No. 03G104A) and SO-244 (Grant No. 03G0244A) were supported by the German Bundesministerium für Bildung und Forschung (BMBF)

The Sahara Slide Complex in Northwest Africa is a giant submarine landslide with an estimated run-out length of ~ 900 km. We present newly acquired high-resolution multibeam bathymetry, sidescan sonar, and sub-bottom profiler data to investigate seafloor morphology, sediment dynamics and the timing of formation of the upper headwall area of the Sahara Slide Complex. The data reveal a ~ 35-km wide upper headwall,opening towards the northwest, with multiple slide scarps, glide planes, plateaus, lobes, slide blocks and slide debris. The slide scarps were generated by retrogressive failure events associated with two types of mass movements: translational sliding and gravitational spreading. As a result of this evolution, three different glide planes (GP I, II, and III) can be distinguished approximately 100 m, 50 m and 20 m below the seafloor. These glide planes are widespread and suggest failure along pronounced, continuous weak layers. Our data suggest an age of only about 2 ka for the failure of the upper headwall area, a date much younger than that derived for landslide deposits on the lower reaches of the Sahara Slide Complex, which are dated at 50–60 ka. The young age of the failure contradicts the postulate of a stable slope offshore Northwest Africa during sea-level highstands. Such an observation suggests that submarine-landslide risk along the continental margin of Northwest Africa should be reassessed based on a robust dating of proximal and distal slope failures.

Distal humerus transphyseal fracture, also referred to as transphyseal separation, is a physeal periarticular elbow injury found most commonly in young children between birth and 3 years of age. Transphyseal fracture of the newborn is rare, occurring in only one of a series of 105,119 live births. It is more common as a result of falls in infants and toddlers. The diagnosis continues to remain difficult due to the cartilaginous nature of the distal humeral epiphysis in this age group, which is not well visualized on plain radiographs. Numerous case series and case reports have described common misdiagnoses including supracondylar humerus fractures, elbow dislocations, lateral condyle fractures, infection, brachial plexus injury, and normal appearance. Classically, the distal fragment is displaced posteromedially, although posterolateral and anterolateral displacement have also been described. Radiographs of the arm will frequently reveal that the axis of the forearm is no longer in line with the humerus. Ultrasound, MRI, and arthrography have also been used to aid in the diagnosis. Historically, treatment has included closed reduction and casting, skin traction, open reduction and internal fixation (ORIF), and closed reduction and percutaneous pinning (CRPP). The most common complications include cubitus varus and loss of flexion and extension; however, avascular necrosis has also been reported.

Highlights • A stack of four BSRs were identified in levee deposits of the Danube deep-sea fan. • The multiple BSRs are not caused by overpressure compartments. • The multiple BSRs reflect stages of stable sealevel lowstands during glacial times. • Gas underneath the previous GHSZ does not start to migrate for thousands of years. Abstract High-resolution 2D seismic data reveal the character and distribution of up to four stacked bottom simulating reflectors (BSR) within the channel-levee systems of the Danube deep-sea fan. The theoretical base of the gas hydrate stability zone (GHSZ) calculated from regional geothermal gradients and salinity data is in agreement with the shallowest BSR. For the deeper BSRs, BSR formation due to overpressure compartments can be excluded because the necessary gas column would exceed the vertical distance between two overlying BSRs. We show instead that the deeper BSRs are likely paleo BSRs caused by a change in pressure and temperature conditions during different limnic phases of the Black Sea. This is supported by the observation that the BSRs correspond to paleo seafloor horizons located in a layer between a buried channel-levee system and the levee deposits of the Danube channel. The good match of the observed BSRs and the BSRs predicted from deposition of these sediment layers indicates that the multiple BSRs reflect stages of stable sealevel lowstands possibly during glacial times. The observation of sharp BSRs several 10,000 of years but possibly up to 300,000 yr after they have left the GHSZ demonstrates that either hydrate dissociation does not take place within this time frame or that only small amounts of gas are released that can be transported by diffusion. The gas underneath the previous GHSZ does not start to migrate for several thousands of years.

Cold seeps on the Hikurangi Margin off New Zealand exhibit various seabed morphologies producing different intensity patterns in sidescan backscatter images. Acoustic backscatter characteristics of 25 investigated seep sites fall into four distinct types characterised by variations in backscatter intensity, distribution and inferred structural heights. The types reflect different carbonate morphologies including up to 20-m-high structures (type 1), low-relief crusts (type 2), scattered blocks (type 3) and carbonate-free sites (type 4). Each seep corresponds to a single type; intermediates were not observed. This correlates well with published data on seep fauna at each site, with the four types representing three different faunal habitats of successive stages of seep development. Backscatter signatures in sidescan sonar images of cold seeps may therefore serve as a convenient proxy for variations in faunal habitats.