ALBERT

Description: Anaerobic oxidation of methane (AOM) was shown to reduce methane emissions by over 50% in freshwater systems, its main natural contributor to the atmosphere. In these environments iron oxides can become main agents for AOM, but the underlying mechanism for this process has remained enigmatic. By conducting anoxic slurry incubations with lake sediments amended with 13C-labeled methane and naturally abundant iron oxides the process was evidenced by significant 13C-enrichment of the dissolved inorganic carbon pool and most pronounced when poorly reactive iron minerals such as magnetite and hematite were applied. Methane incorporation into biomass was apparent by strong uptake of 13C into fatty acids indicative of methanotrophic bacteria, associated with increasing copy numbers of the functional methane monooxygenase pmoA gene. Archaea were not directly involved in füll methane oxidation, but their crucial participation,likely being mediators in electron transfer, was indicated by specific inhibition of their activity that fully stopped iron-coupled AOM. By contrast, inhibition of sulfur cycling increased 13C-methane turnover, pointing to sulfur species involvement in a competing process. Our findings suggest that the mechanism of iron-coupled AOM is accomplished by a complex microbemineral reaction network, being likely representative of many similar but hidden interactions sustaining life under highly reducing low energy conditions.

Description: Climate change has significant implications for biodiversity and ecosystems. With slow progress towards reducing greenhouse gas emissions, climate engineering (or ‘geoengineering’) is receiving increasing attention for its potential to limit anthropogenic climate change and its damaging effects. Proposed techniques, such as ocean fertilization for carbon dioxide removal or stratospheric sulfate injections to reduce incoming solar radiation, would significantly alter atmospheric, terrestrial and marine environments, yet potential side-effects of their implementation for ecosystems and biodiversity have received little attention. A literature review was carried out to identify details of the potential ecological effects of climate engineering techniques. A group of biodiversity and environmental change researchers then employed a modified Delphi expert consultation technique to evaluate this evidence and prioritize the effects based on the relative importance of, and scientific understanding about, their biodiversity and ecosystem consequences. The key issues and knowledge gaps are used to shape a discussion of the biodiversity and ecosystem implications of climate engineering, including novel climatic conditions, alterations to marine systems and substantial terrestrial habitat change. This review highlights several current research priorities in which the climate engineering context is crucial to consider, as well as identifying some novel topics for ecological investigation.

Description: Highlights • The Fram Slide Complex has been active from late Miocene to late Pleistocene. • Local processes were critical for slope stability in the Fram Strait area. • Toe erosion caused by normal faulting may have led to retrogressive failure. • Low gradient contourite drifts might smooth and stabilize submarine slopes. • Low tsunami potential from the Fram Slide Complex could increase in the future. Abstract The best known submarine landslides on the glaciated NW European continental margins are those at the front of cross-shelf troughs, where the alternation of rapidly deposited glycogenic and hemi pelagic material generates sedimentary overpressure. Here, we investigate landslides in two areas built of contourite drifts bounded seaward by a ridge-transform junction. Seismic and bathymetric data from the Fram Slide Complex are compared with the tectonically similar Vastness area ~ 120 km to the south, to analyze the influence of local and regional processes on slope stability. These processes include tectonic activity, changes of climate and oceanography, gas hydrates and fluid migration systems, slope gradient, toe erosion and style of contourite deposition. Two areas within the Fram Slide Complex underwent different phases of slope failures, whereas there is no evidence at all for major slope failures in the Vastness area. The comparison cannot reveal the distinct reason for slope failure but demonstrates the strong impact of variation in the local controls on slope stability. The different failure chronologies suggest that toe erosion, which is dependent on the throw of normal faults, and the different thickness and geometry of contourite deposits can result in a critical slope morphology and exert pronounced effects on slope stability. These results highlight the limitations of regional hazard assessments and the need for multi-disciplinary investigations, as small differences in local controlling factors led to substantially different slope failure histories.

Description: https://datadryad.org/stash/dataset/doi:10.5061/dryad.10rk4

Description: The surface chemistry of aquatic organisms determines their biotic interactions. Metabolites in the spatially limited laminar boundary layer mediate processes, such as antifouling, allelopathy and chemical defense against herbivores. However, very few methods are available for the investigation of such surface metabolites. An approach is described in which surfaces are extracted by means of C18 solid phase material. By powdering wet algal surfaces with this material, organic compounds are adsorbed and can be easily recovered for subsequent liquid chromatography/mass spectrometry (LC/MS) and gas chromatography/mass spectrometry (GC/MS) investigations. The method is robust, picks up metabolites of a broad polarity range and is easy to handle. It is more universal compared to established solvent dipping protocols and it does not cause damage to the test organisms. A protocol is introduced for the macroalgae Fucus vesiculosus, Caulerpa taxifolia and Gracilaria vermiculophylla, but it can be easily transferred to other aquatic organisms.

Description: For assessing the tsunamigenic potential, the mechanical strength, composition and fabric of forearc slope and accreted sediments from the Nankai Trough offshore SW-Japan have been investigated (NanTroSEIZE; IODP expeditions 315, 316, 333). Triaxial testing of shallow whole round samples (maximum depth of 130 mbsf) at confining pressures of 0.4-1.0 MPa, room temperature, strain rates of approx. 10-3 to 10-6s-1, and up to 64% axial strain (Stipp et al., 2013) revealed mechanically and structurally weak samples from the upper and middle forearc slope of the accretionary prism and strong samples from the accretionary prism toe (Stipp et al., 2013). In order to constrain these results, three additional experiments on samples from greater depth (211-221 mbsf) at confining pressures of 3.0-8.0 MPa, room temperature, strain rates of approx. 10-5s-1, and up to 54% axial strain were carried out. For these tests a digitally controlled servo-hydraulic triaxial appartus with a maximum load of 100 kN was used. Correspondingly to the shallow samples, these experiments show a deviatoric peak stress after only a few percent strain (〈10%) and a continuous stress decrease after this maximum combined with a continuous increase in pore pressure indicative of structurally weak behavior for the two forearc slope samples. The sample from the prism toe area, however, displays a continuous stress increase together with a decrease in pore pressure towards high strain indicative of structurally strong behavior. Synchrotron texture and composition analysis of the experimentally deformed and undeformed samples using the Rietveld refinement program MAUD indicates an increasing strength of the illite and kaolinite textures with increasing depth down to 523 m below sea floor corresponding to a shape preferred mineral alignment due to compaction (Schumann et al., 2014). Experimentally deformed samples have generally stronger textures than related undeformed core samples, and they show increasing strength of the illite and kaolinite textures with increasing axial strain. Mechanically weak samples have a bulk clay plus calcite content of 31-65 vol.-% and most of their illite, kaolinite, smectite and calcite (001)-pole figures have maxima 〉1.5 mrd (multiples of a random distribution). Mechanically strong samples, which were deformed to approximately the same amount of strain (up to 40%) have no calcite and a bulk clay content of 24-36 vol.-%. Illite, kaolinite and smectite (001)-pole figure maxima are predominantly 〈1.5 mrd. The synchrotron textures indicate that the mineral fabric as a whole (clay and also calcite grains) becomes preferentially oriented in the mechanically weak samples. Reorientation of the mineral grains is an important cause of strain weakening and contraction, persisting to high compressive strains. In contrast, the strong samples from the accretionary prism toe keep their microfabric up to fairly high compressive strain, allowing for strain hardening and dilation. This soft sediment hardening tends to involve increasingly large volumes of sediment into the imposed deformation, permitting strain dissipation as long as the sediments are homogeneous. Deformation will tend to localize into structurally weak sediments if they occur within the lithological sequence. Such weak sediments, which soften further with increasing strain, predominate in the cover units of the forearc slope and around the existing megasplay fault. They may either provoke mechanical runaway situations allowing for earthquake rupture, surface breakage and tsunami generation, or slope destabilization and resulting submarine mass wasting.

Description: The present-day structure of the southern Adriatic area is controlled by two oppositely-vergent fold-and-thrust belt systems (Apennines and Dinarides). The Adriatic continental domain is one of the most enigmatic segments of the Alpine-Mediterranean collision zone. It separated from the African plate during the Mesozoic extensional phase that led to the opening of the Ionian Sea. Basin widening and deepening peaked during Late Triassic-Liassic extension, resulting in the formation of the southern Adriatic basin, bounded on either side by the Dinaric and Apulian shallow water carbonate platforms. Because of its present foreland position with respect to the Dinaric part of orogenic belt, the southern Adriatic basin represents the only remnant of the Neotethyan margin and offers the unique opportunity to image a segment of Mesozoic passive margin in the Mediterranean. To study the deep crustal structure, the upper mantle and the shape of the plate margin, the German research vessel Meteor acquired 2D seismic refraction and wide-angle reflection data during an onshore-offshore experiment (cruise M86-3). We present two profiles: Profile P03 crossed Adria from the Gargano Promontory into Albania. A second profile (P01) was shot parallel to the coastlines, extending from the southern Adriatic basin to a possible mid-Adriatic strike-slip fault that purportedly segments the Adriatic microplate. Two different approaches of travel time tomography are applied to the data set: A non-linear approach is used for the shorter profile P01. A linear approach is applied to profile P03 (360 km length) and allows for the integration of the 36 ocean bottom stations and 19 land stations. First results show a good resolution of the sedimentary part of the Adriatic region. The depth of the basement as well as the depth of the Moho discontinuity vary laterally and deepen towards the North-East, consistent with the notion of flexural loading of the externally propagating orogenic wedge of the Dinarides.

Description: Lake Ohrid (LO), a transboundary lake shared by Macedonia and Albania on the Balkan Peninsula, is not only considered to be the oldest lake in Europe (~2 Ma) but has a long and continuous sedimentary history. An advantage at LO is the availability of hydroacoustic data sets of good quality covering the entire lake basin. The tectonically formed basin is filled with thick undisturbed sediments. However, the overall internal structure of LO is characterized by numerous faults, clinoform structures, and several Mass Transport Deposits (MTDs). By using a seismic chronology model (SCM) correlating seismic reflector packages with Marine Isotope Stages (MIS) we estimate the occurrence of the deepest MTD detected in the southern basin at the transition of MIS9 to MIS8 (~300 ka) defining the onset of the sliding history in LO that is still ongoing today. In general, MTDs are widespread within the basin but they do cluster at active faults. Two large MTDs occurred in the early MIS7 (~230 ka, ~220 ka) and after a quiesence period of about ~70 ka two additional large MTDs have been detected in the late penultimate glacial period MIS6 (~150 ka, 130 ka). MIS5 seemed to be another quiet period with respect to mass wasting. In the younger sedimentary history mass movement is a common process with several large and mid-sized deposits mapped at all stratigraphic levels. The youngest slide deposits are estimated to occur within the last 2,000 years. The main outcome of this paper is a model for the spatial and temporal distribution of mass wasting for Lake Ohrid.

Description: We used a new sedimentary record from a small kettle wetland to reconstruct the Late Glacial and Holocene vegetation and fire history of the Krutoberegovo-Ust Kamchatsk region in eastern Kamchatka Peninsula (Russia). Pollen and charcoal data suggest that the Late Glacial landscape was dominated by a relatively fire-prone Larix forest-tundra during the Greenland Interstadial complex (GI 1) and a subarctic steppe during the Younger Dryas (GS1). The onset of the Holocene is marked by the reappearance of trees (mainly Alnus incana) within a fern and shrub dominated landscape. The Holocene Thermal Maximum (HTM) features shifting vegetational communities dominated by Alnus shrubs, diverse forb species, and locally abundant aquatic plants. The HTM is further defined by the first appearance of stone birch forests (Betula ermanii) – Kamchatka's most abundant modern tree species. The Late Holocene is marked by shifts in forest dynamics and forest-graminoid ratio and the appearance of new non-arboreal taxa such as bayberry (Myrica) and meadow rue (Filipendula). Kamchatka is one of Earth's most active volcanic regions. During the Late Glacial and Holocene, Kamchatka's volcanoes spread large quantities of tephra over the study region. Thirty-four tephra falls have been identified at the site. The events represented by most of these tephra falls have not left evidence of major impacts on the vegetation although some of the thicker tephras caused expansion of grasses (Poaceae) and, at least in one case, forest die-out and increased fire activity.

Description: Highlights • Receiver functions from ocean-bottom seismometer stations reveal no significant crustal thickening in the surrounding of the Tristan da Cunha hot spot. • The mantle transition zone to the NW of Tristan da Cunha is thickened and cool. • The mantle transition zone is potentially thinned to the south/southwest of Tristan da Cunha. • A thickness of 60 to 75 km beneath Tristan da Cunha argues for a compositional control on the seismological lithosphere in the South Atlantic. Abstract The most prominent hotspot in the South Atlantic is Tristan da Cunha, which is widely considered to be underlain by a mantle plume. But the existence, location and size of this mantle plume have not been established due to the lack of regional geophysical observations. A passive seismic experiment using ocean bottom seismometers aims to investigate the lithosphere and upper mantle structure beneath the hotspot. Using the Ps receiver function method we calculate a thickness of 5 to 8 km for the oceanic crust at 17 ocean-bottom stations deployed around the islands. Within the errors of the method the thickness of the oceanic crust is very close to the global mean. The Tristan hotspot seems to have contributed little additional magmatic material or heat to the melting zone at the mid-oceanic ridge, which could be detected as thickened oceanic crust. Magmatic activity on the archipelago and surrounding seamounts seems to have only effected the crustal thickness locally. Furthermore, we imaged the mantle transition zone discontinuities by analysing receiver functions at the permanent seismological station TRIS and surrounding OBS stations. Our observations provide evidence for a thickened (cold) mantle transition zone west and northwest of the islands, which excludes the presence of a deep-reaching mantle plume. We have some indications of a thinned, hot mantle transition zone south of Tristan da Cunha inferred from sparse and noisy observations, which might indicate the location of a Tristan mantle plume at mid-mantle depths. Sp receiver functions image the base of lithosphere at about 60 to 75 km beneath the islands, which argues for a compositionally controlled seismological lithosphere-asthenosphere boundary beneath the study area.

Description: Highlights • Observations show that formation of sediment-laden sea ice occurs in coastal polynyas in winter. • Sea ice rafted sediments are a significant component of the Laptev Sea’s sediment budget. • No observational evidence for sediment entrainment into sea ice in mid-shelf polynyas at water depth greater than 20 m. Abstract Sea ice is an important vehicle for sediment transport in the Arctic Ocean. On the Laptev Sea shelf (Siberian Arctic) large volumes of sediment-laden sea ice are formed during freeze-up in autumn, then exported and transported across the Arctic Ocean into Fram Strait where it partly melts. The incorporated sediments are released, settle on the sea floor, and serve as a proxy for ice-transport in the Arctic Ocean on geological time scales. However, the formation process of sediment-laden ice in the source area has been scarcely observed. Sediment-laden ice was sampled during a helicopter-based expedition to the Laptev Sea in March/April 2012. Sedimentological, biogeochemical and biological studies on the ice core as well as in the water column give insights into the formation process and, in combination with oceanographic process studies, on matter fluxes beneath the sea ice. Based on satellite images and ice drift back-trajectories the sediments were likely incorporated into the sea ice during a mid-winter coastal polynya near one of the main outlets of the Lena River, which is supported by the presence of abundant freshwater diatoms typical for the Lena River phytoplankton, and subsequently transported about 80 km northwards onto the shelf. Assuming ice growth of 12 to 19 cm during this period and mean suspended matter content in the newly formed ice of 91.9 mg l-1 suggests that a minimum sediment load of 8.4x104 t might have been incorporated into sea ice. Extrapolating these sediment loads for the entire Lena Delta region suggests that at least 65% of the estimated sediment loads which are incorporated during freeze-up, and up to 10% of the annually exported sediment load may be incorporated during an event such as described in this paper.

Description: Experimental studies linking community composition to functioning are typically confined to small and closed micro- or mesocosms. Such restricted conditions may affect both species’ biology and their environment. Yet, targeting simple features in the behaviour of species may circumvent these constraints. Focusing on ecological functions provided by dung beetles, we test whether large, open-top cages – MESOCLOSURES – will intercept the flight trajectories of beetles, thereby allowing manipulation of local community composition. MESOCLOSURES were built in both tropical forest (Brazil) and temperate grasslands (Finland), thus testing their general efficiency. Within the respective environments, we varied different aspects of MESOCLOSURE design: in the tropical forest, we examined the impact of MESOCLOSURE dimensions on exclusion efficiency, whereas in the temperate grassland, we assessed the potential for selectively excluding and including community members by different mesh sizes. In the temperate environment, we also went from method to application, using MESOCLOSURES to relate community composition to functioning under two simulated grazing regimes. MESOCLOSURES allowed efficient manipulation of dung beetle communities, maintaining dung beetle densities at intended levels in both temperate and tropical systems. In the tropics, the smallest cages (1 × 1 m) offered the highest contrast in beetle densities inside vs. outside of the fence, whereas the largest cages (9 × 9 m) offered the lowest. Nonetheless, densities inside cages never exceed one-fifth of those outside. At the temperate site, manipulations of community structure through mesh size yielded significant differences in functioning and suggested an interaction between small dung-dwelling species and large tunnelling species. Within cages, higher grazing was reflected in augmented dung removal. We conclude that MESOCLOSURES can be effectively used to study dung beetle functions across habitats and latitudes. As applied insights, the present study adds resolution to the significance of different functional groups of dung beetles and shows that grazing pressure may have an important impact on the ecosystem functions that they provide. Overall, this study suggests that targeted manipulation of dispersal may offer new solutions for linking fauna to ecosystem functions with minimal impact on the processes measured.

Description: The Denmark Strait Overflow (DSO) contributes roughly half to the total volume transport of the Nordic overflows. The overflow increases its volume by entraining ambient water as it descends into the subpolar North Atlantic, feeding into the deep branch of the Atlantic Meridional Overturning Circulation. In June 2012, a multiplatform experiment was carried out in the DSO plume on the continental slope off Greenland (180 km downstream of the sill in Denmark Strait), to observe the variability associated with the entrainment of ambient waters into the DSO plume. In this study, we report on two high-dissipation events captured by an autonomous underwater vehicle (AUV) by horizontal profiling in the interfacial layer between the DSO plume and the ambient water. Strong dissipation of turbulent kinetic energy of O( math formula) W kg−1 was associated with enhanced small-scale temperature variance at wavelengths between 0.05 and 500 m as deduced from a fast-response thermistor. Isotherm displacement slope spectra reveal a wave number-dependence characteristic of turbulence in the inertial-convective subrange ( math formula) at wavelengths between 0.14 and 100 m. The first event captured by the AUV was transient, and occurred near the edge of a bottom-intensified energetic eddy. Our observations imply that both horizontal advection of warm water and vertical mixing of it into the plume are eddy-driven and go hand in hand in entraining ambient water into the DSO plume. The second event was found to be a stationary feature on the upstream side of a topographic elevation located in the plume pathway. Flow-topography interaction is suggested to drive the intense mixing at this site.

Description: The Integrated Plate Boundary Observatory Chile (IPOC) in northern Chile has been monitoring the largest seismic gap along the South American subduction zone for 10 years. When IPOC was initiated, it has been 130 years the last great earthquake in the region had occurred. And since then the Iquique gap had been accumulating a slip deficit along a 〉500 km segment of the plate boundary. Since IPOC’s inception two large events, the 2007 M 7.7 Tocopilla and the M 8.1 2014 Iquique earthquakes, have broken parts of the gap. Both events were well recorded by IPOC, produce valuable data and advance our understanding of the subduction megathrust earthquake cycle. Last year, the Helmholtz Centre for Ocean Research Kiel (GEOMAR) has been extending IPOC with the GeoSEA ocean bottom observatory. In this ambitious project deformation will be measured where it cannot be picked up by land-based instruments, i. e. far offshore near the subduction trench. This will open the crucial updip section of the subduction plate boundary to research. IPOC has thus demonstrated the necessity of long-term monitoring to observe slow or rare events, but also that tenacity and patience pay off.

Description: Subduction of the oceanic plate plays an important role in the various processes in subduction zones, including arc magmatism and generation of earthquakes. Thus the nature of the incoming plate, such as its relief, thermal state, lithology, and the water content, are considered to shape these subduction zone processes. In 2014 and 2015, to reveal the nature of the incoming plate in the ocean-ward area of the 2011 M9 Tohoku earthquake, we conducted wide-angle seismic surveys in the trench-outer rise region of the Japan Trench. We designed a 600 km long seismic survey line perpendicular to the trench axis and deployed 88 OBSs at intervals of 6 km and shot a tuned airgun array of R/V Kairei. We have applied a traveltime inversion to model the P-wave velocity (Vp) structure. The resulting Vp model shows that Vp within the oceanic crust and the topmost mantle decreases in the vicinity of the trench axis probably due to the plate bending. In addition, we observed low Vp at the top of the oceanic crust in the area of petit spot volcanos. The low Vp area may be related to magma intrusions because we observed several structural interfaces in the shallow area. We found two structural features that we did not anticipate. First, crustal thickness abruptly changes at around the center of our survey line (~300-km east from the trench axis); crust thickness is 7-km in the west and 6-km in the east. Second, mantle Vp shows significant variations along the survey line, ~7.5 km/s in the bend-fault area (western area), 8.0 km/s around the center, 8.5 km/s in the eastern area. Based on the shear wave splitting observed in our data set, we infer that high mantle Vp in the eastern area is related with the changes in the orientation of the mantle anisotropy. Since we do not see any remarkable topographic features indicating the off-ridge activities, we consider that these observed structural features are related with the activities near the ancient spreading ridge when the oceanic plate formed, indicating that the oceanic plate in the NW Pacific margin, the input to the northeastern Japanese island arc, is more complicated here than we previously thought. In this presentation, we will show an overview of the Vp model along the whole profile and detailed seismic structure beneath the petit-spot area derived by the P-to-S converted waves.

Description: Dommenget (2010) found that El Niño-like variability, termed Slab Ocean El Niño, can exist in the absence of ocean dynamics and is driven by the interaction of the atmospheric surface heat fluxes and the heat content of the upper ocean. Further, Dommenget et al. (2014) report the Slab Ocean El Niño is not an artefact of the ECHAM5-AGCM coupled to a slab ocean model. In fact, atmospheric feedbacks crucial to the Slab Ocean El Niño can also be found in many state-of-the-art coupled climate models participating in CMIP3 and CMIP5, so that ENSO in many CMIP models can be understood as a mixed recharge oscillator/Slab Ocean El Niño mode. Here we show further analysis of the Slab Ocean El Niño atmospheric feedbacks in coupled models. The BCCR_CM2.0 climate model from the CMIP3 data base, which has a very large equatorial cold bias, has an El Niño that is purely driven by Slab Ocean El Niño atmospheric feedbacks and is used as an example to describe Slab Ocean El Niño atmospheric feedbacks in a coupled model. In the BCCR_CM2.0, the ENSO-related variability in the 20°C isotherm (Z20), a measure of upper ocean heat content, is decoupled from the first mode of the seasonal cycle-related variability, while the two are coupled in observations, with ENSO being phase-locked to the seasonal cycle. Further analysis of the seasonal cycle in Z20 using SODA Ocean Reanalysis reveals two different regimes in the seasonal cycle along the equator: The first regime, to which ENSO is phase-locked, extends over the west and central equatorial Pacific and is driven by subsurface ocean dynamics. The second regime, extending in observations only over the cold tongue region, is driven by the seasonal cycle at the sea surface and is shifted by roughly six months relative to the first regime. In a series of experiments with the Kiel Climate Model (KCM) with different mean states due to tuning in the convection parameters, we can show that the strength of the equatorial cold bias and the coupling strength between the seasonal cycle of Z20 and ENSO are anti-correlated, i.e. a strong equatorial cold bias suppresses recharge oscillator dynamics and enhances Slab Ocean El Niño atmospheric feedbacks, supporting the results from the BCCR_CM2.0. This can be explained as with a stronger cold bias the second regime of the seasonal cycle in Z20, which extends in observations only over the small cold tongue region, expands westward and becomes more important, so that it decouples ENSO from the seasonal cycle in Z20. This has implications for some major characteristics of the ENSO like the propagation of SST anomalies, the phase locking of SST to the seasonal cycle, or the nonlinearity of ENSO. Dommenget, D., 2010: The slab ocean El Niño. Geophys. Res. Lett., 37, L20701, doi:10.1029/2010GL044888. ——, S. Haase, T. Bayr, and C. Frauen, 2014: Analysis of the Slab Ocean El Niño atmospheric feedbacks in observed and simulated ENSO dynamics. Clim. Dyn., doi:10.1007/s00382-014-2057-0.

Description: The Eastern Baltic cod abundance started rapidly to increase in the mid-2000s as evidenced by analytical stock assessments, due to increased recruitment and declining fishing mortality. Since 2014, the analytical stock assessment is not available, leaving the present stock status unclear and casting doubts about the magnitude of the recent increase in recruitment. Earlier studies identified main factors impacting on cod reproductive success to be related to the loss of two out of three spawning areas in the 1980s caused by lack of major Baltic inflows with a concurrent reduction in salinity and oxygen. Other important factors include prey availability for first-feeding larvae, egg predation by sprat and herring and cannibalism on juveniles, all in one way or the other related to the prevailing hydrographic conditions. These factors cannot explain increased reproductive success in the last decade, as the period was characterized by an absence of large-scale Baltic inflows since 2003 and persistent anoxic conditions in the bottom water of the deep Baltic basins. This questions the perception of the increased recruitment in later years and challenges our present understanding of cod recruitment dynamics in the Baltic Sea. In this contribution, we review evidence from the recent literature supplemented by information from latest research cruises to elucidate whether cod reproductive success indeed has increased during the last decade, and we suggest the key processes responsible for the recent dynamics in cod recruitment and outline directions for future research.

Description: The recent volcanic eruptions of Eyjafjallajökull 2010 and Grímsvötn 2011 demonstrated the risks that mediumsized explosive Icelandic eruptions pose to the North Atlantic region. Using the Eyjafjallajökull 2010 eruption as a case study, we assess how traceable such eruptions are in the marine sedimentary record at medial distances from the source and investigate which factors have affected the particle transport to the marine sedimentary archive. During R/V Poseidon cruise 457, we recovered 13 box cores at 100–1600 m water depths and distances of 18–180 km southwest, south, and east of Iceland. Volcanic glass shards from the uppermost surface sediment were analyzed for their major element composition by electron microprobe and assigned to their eruptive source by geochemical fingerprinting. The predominantly basaltic particles are mostly derived from the Katla, Grímsvötn-Lakagígar, and Bárðarbunga-Veiðivötn volcanic systems. We also identified rhyolitic particles from the Askja 1875 and Öræfajökull 1362 eruptions. Only three out of almost 900 analyzed glass shards are derived from the recent Eyjafjallajökull 2010 eruption, suggesting that medium-sized eruptions are only poorly preserved in marine sediments located at medial distances southwest to east of Iceland. We conclude that the frequency of past medium-sized eruptions is likely higher than detectable in this archive.

Description: Environmental histories that span the last full glacial cycle and are representative of regional change in Australia are scarce, hampering assessment of environmental change preceding and concurrent with human dispersal on the continent ca. 47,000 years ago. Here we present a continuous 150,000-year record offshore south-western Australia and identify the timing of two critical late Pleistocene events: wide-scale ecosystem change and regional megafaunal population collapse. We establish that substantial changes in vegetation and fire regime occurred B70,000 years ago under a climate much drier than today. We record high levels of the dung fungus Sporormiella, a proxy for herbivore biomass, from 150,000 to 45,000 years ago, then a marked decline indicating megafaunal population collapse, from 45,000 to 43,100 years ago, placing the extinctions within 4,000 years of human dispersal across Australia. These findings rule out climate change, and implicate humans, as the primary extinction cause.

Description: 28.10. - 22.12.2016

Description: Ocean observations in the oxygen minimum zone (OMZ) of the eastern tropical North Atlantic (ETNA) are analyzed to study decadal oxygen variability. Corresponding changes in hydrography are discussed and associated with changes in the circulation and ventilation. The data set consists of repeat shipboard hydrographic, oxygen and velocity observations along 23°W as well as of three multi-year long moored observations both acquired during the last decade. It is examined in comparison to historic hydrographic data on a decadal to multi-decadal time scale perspective. During the last decade, a strong deoxygenation was observed at depth of the deep oxycline representing a shallowing of the ETNA OMZ, while oxygen increased below in the OMZ core. Both trends are superimposed with a moderate multi-decadal oxygen decrease over the whole depth range. Water mass analysis indicates that this dipole pattern in the decadal oxygen variability is associated with a shift in the ventilation pathways having their origin either in the northern or southern hemisphere. The decadal and multi-decadal oxygen trend is implemented in the oxygen budget for the ETNA OMZ, which is based on recent estimates of oxygen consumption as well as lateral and diapycnal diffusive oxygen supply. The change in the residual of this oxygen budget derived from multi-decadal and decadal oxygen trend patterns indicates a shallower wind-driven near-surface circulation during the last decade compared to the period before. In contrast, the latitudinally alternating zonal jets that were suggested to generally weaken since the 70ies might have intensified during the last decade providing the enhanced oxygen supply at the core depth of the OMZ.

Description: Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope instability. Minor slide deposits and an internally-deformed sedimentary layer near the base of the gas hydrate stability zone imply an incomplete failure event, most probably about 30000 years ago, contemporaneous to or shortly after the Hinlopen/Yermak Megaslide. An active gas reservoir at the base of the gas hydrate stability zone demonstrate that over-pressured fluids might have played a key role in the initiation of slope failure at the studied slope, but more importantly also for the giant HYM slope failure. To date, it is not clear, if the studied slope is fully preconditioned to fail completely in future or if it might be slowly deforming and creeping at present. We detected widespread methane seepage on the adjacent shallow shelf areas not sealed by gas hydrates.

Description: Highlights: • Fungal infections represent an increasing threat to human health. • Fungal infections in plants are a worldwide problem to the agricultural industry. • Diverse antifungal compounds were isolated from different marine organisms. • The number of new antifungal marine natural products is rapidly developing. • Marine sponges and bacteria are the predominant sources for antifungal compounds. Abstract: Fungal diseases represent an increasing threat to human health worldwide which in some cases might be associated with substantial morbidity and mortality. However, only few antifungal drugs are currently available for the treatment of life-threatening fungal infections. Furthermore, plant diseases caused by fungal pathogens represent a worldwide economic problem for the agriculture industry. The marine environment continues to provide structurally diverse and biologically active secondary metabolites, several of which have inspired the development of new classes of therapeutic agents. Among these secondary metabolites, several compounds with noteworthy antifungal activities have been isolated from marine microorganisms, invertebrates, and algae. During the last fifteen years, around 65% of marine natural products possessing antifungal activities have been isolated from sponges and bacteria. This review gives an overview of natural products from diverse marine organisms that have shown in vitro and/or in vivo potential as antifungal agents, with their mechanism of action whenever applicable. The natural products literature is covered from January 2000 until June 2015, and we are reporting the chemical structures together with their biological activities, as well as the isolation source.

Description: MSM59/1-2, 28.10. - 22.12.2016

Description: Polymetallic nodule mining at abyssal depths in the Clarion Clipperton Fracture Zone (Eastern Central Pacific) will impact one of the most remote and least known environments on Earth. Since vast areas are being targeted by concession holders for future mining, large-scale effects of these activities are expected. Hence, insight into the fauna associated with nodules is crucial to support effective environmental management. In this study video surveys were used to compare the epifauna from sites with contrasting nodule coverage in four license areas. Results showed that epifaunal densities are more than two times higher at dense nodule coverage (〉25 versus ≤10 individuals per 100 m2), and that taxa such as alcyonacean and antipatharian corals are virtually absent from nodule-free areas. Furthermore, surveys conducted along tracks from trawling or experimental mining simulations up to 37 years old, suggest that the removal of epifauna is almost complete and that its full recovery is slow. By highlighting the importance of nodules for the epifaunal biodiversity of this abyssal area, we urge for cautious consideration of the criteria for determining future preservation zones.

Description: New high-precision minor element analysis of the most magnesian olivine cores (Fo85–88) in fifteen high-MgO (Mg#66–74) alkali basalts or trachybasalts from the Quaternary backarc volcanic province, Payenia, of the Andean Southern Volcanic Zone in Argentina displays a clear north-to-south decrease in Mn/Feol. This is interpreted as the transition from mainly peridotite-derived melts in the north to mainly pyroxenite-derived melts in the south. The peridotite–pyroxenite source variation correlates with a transition of rock compositions from arc-type to OIB-type trace element signatures, where samples from the central part of the province are intermediate. The southernmost rocks have, e.g., relatively low La/Nb, Th/Nb and Th/La ratios as well as high Nb/U, Ce/Pb, Ba/Th and Eu/Eu* = 1.08. The northern samples are characterized by the opposite and have Eu/Eu* down to 0.86. Several incompatible trace element ratios in the rocks correlate with Mn/Feol and also reflect mixing of two geochemically distinct mantle sources. The peridotite melt end-member carries an arc signature that cannot solely be explained by fluid enrichment since these melts have relatively low Eu/Eu*, Ba/Th and high Th/La ratios, which suggest a component of upper continental crust (UCC) in the metasomatizing agent of the northern mantle. However, the addition to the mantle source of crustal materials or varying oxidation state cannot explain the variation in Mn and Mn/Fe of the melts and olivines along Payenia. Instead, the correlation between Mn/Feol and whole-rock (wr) trace element compositions is evidence of two-component mixing of melts derived from peridotite mantle source enriched by slab fluids and UCC melts and a pyroxenite mantle source with an EM1-type trace element signature. Very low Ca/Fe ratios (~1.1) in the olivines of the peridotite melt component and lower calculated partition coefficients for Ca in olivine for these samples are suggested to be caused by higher H2O contents in the magmas derived from subduction zone enriched mantle. Well-correlated Mn/Fe ratios in the wr and primitive olivines demonstrate that the Mn/Fewr of these basalts that only fractionated olivine and chromite reflects the Mn/Fe of the primitive melts and can be used as a proxy for the amount of pyroxenite melt in the magmas. Using Mn/Fewr for a large dataset of primitive Payenia rocks, we show that decreasing Mn/Fewr is correlated with decreasing Mn and increasing Zn/Mn as expected for pyroxenite melts.

Description: To perform environmental monitoring of deep-sea drill sites (e.g., gas leakage and seafloor deformation) and for optimal placement of monitoring equipment on the seafloor, the exact fault trace and any possible fault offsets need to known. We mapped the structures around a growth fault near the gas hydrate drill site. Then, based on the contour lines, we derived individual two-dimensional (2D) chirp data and merged 3D volumes. The chirp data revealed a clear growth fault slightly south (about 210 m) of drill site. The fault was mapped across all inlines of the 3D volumes. Fault offsets were determined for five individual layers and a clear change in offset with depth was observed. A reduced offset was noted below layer L2 (~1 m) but it was to 2.5 m for both underlying layers L3 and L4. Based on five piston cores across the survey area between North Zone and South Zone, the linear sedimentation rate for the Holocene showed almost no difference (16.5–16.7 cm/kyr). The rate below the Holocene showed a difference between the North Zone (lower; 12.6–12.8 cm/kyr) and the South Zone (higher; 14.8–16.1 cm/kyr). This change is explained by a sudden reduction of fault activity during the Holocene.

Description: The Ontong Java and Manihiki oceanic plateaus are believed to have formed through high-degree melting of a mantle plume head. Boninite-like, low-Ti basement rocks at Manihiki, however, imply a more complex magma genesis compared with Ontong Java basement lavas that can be generated by ∼30% melting of a primitive mantle source. Here we show that the trace element and isotope compositions of low-Ti Manihiki rocks can best be explained by re-melting of an ultra-depleted source (possibly a common mantle component in the Ontong Java and Manihiki plume sources) re-enriched by ≤1% of an ocean-island-basalt-like melt component. Unlike boninites formed via hydrous flux melting of refractory mantle at subduction zones, these boninite-like intraplate rocks formed through adiabatic decompression melting of refractory plume material that has been metasomatized by ocean-island-basalt-like melts. Our results suggest that caution is required before assuming all Archaean boninites were formed in association with subduction processes.

Description: MSM59/1-2, 28.10. - 22.12.2016

Description: MSM59/1-2, 28.10. - 22.12.2016

Description: Deep-water corals can form structurally complex habitats that harbour diverse associated fauna. Although largely hidden from view, these habitats are susceptible to anthropogenic impacts such as fishing with bottom contacting gear. Over the past decades, scientific interest in deep-water corals has intensified and following the discovery of the extent of human impacts to these vulnerable ecosystems, multiple conservation areas have been established. To date, information on coral ecosystem recovery capacity and thus the effectiveness of conservation measures remain scarce. Insights on key ecological traits of deep-water corals can aid marine spatial planning and management of deep-water coral conservation areas. In this thesis, I studied distribution patterns as well as changes in growth and abundance of coral colonies over time in the Northeast Channel Coral Conservation Area (NECCCA) established at the entrance to the Gulf of Maine in 2002. Analyses were based on videos collected by a remotely operated vehicle (ROV) in 2001, 2006, 2010 and 2014. I evaluate the recovery potential of the two dominant coral species in the NECCCA and present how information on distribution, abundance and growth of corals can be used to inform marine spatial planning...

Description: In 2011, twelve ocean bottom stations (OBS) were installed approximately 100 km North of the Gloria Fault during the DOCTAR project (Deep OCean Test ARray). This fault marks the plate boundary between the Eurasian and African plate in the North Eastern Mid Atlantic. The experiment took place in water depth of 4-6 km, 800 km West of the Portuguese coast. The stations were equipped with broad band seismometers which recorded for ten months. We employ P and S receiver functions (RF) to have a closer look at the structure of crust and mantle. The ocean is a quite noisy environment, therefore the number of usable events is low (around 20) compared to RF studies on land. We use several quality criteria (e.g. signal to noise ratio, relative spike position) to select proper processing parameters for the calculation of the RF and carefully reviewed all later on used RF. Despite the low number of events, the usage of an array of OBS with an aperture of 75 km allows us to investigate deeper discontinuities (e.g. in 410 and 660 km depth) compared to single station approaches which are usually employed for OBS. Furthermore, we increase the number of usable events by applying array methods. We use move out corrected and stacked RF to have a closer look at the mantle transition zone, and estimate average depth values for the Moho, the lithosphere asthenosphere boundary (LAB) and the base of the asthenosphere. The Moho lies at depth of 7 km, the LAB at approximately 50 km and the asthenosphere has an approximated thickness of 110 km. We observe a slight increase in the time difference of the mantle discontinuity conversion times compared to PREM. RF give just information regarding the impedance contrast at a discontinuity instead of velocities. We additionally use P wave polarization of teleseismic events to estimate absolute S velocities beneath the single stations. All in all, we use the information gained by the RF analysis, and the analysis of the P wave polarization to construct a 1D velocity model. A comparison with synthetic RF is used to further tune the gained model.

Description: Oxygen minimum zones (OMZs) are often characterized by nitrogen-to-phosphorus (N:P) ratios far lower than the canonical Redfield ratio. Whereas, the importance of variable stoichiometry in phytoplankton has long been recognized, variations in zooplankton stoichiometry have received much less attention. Here we combine observations from two shipboard mesocosm nutrient enrichment experiments with an optimality-based plankton ecosystem model, designed to elucidate the roles of different trophic levels and elemental stoichiometry. Pre-calibrated microzooplankton parameter sets represent foraging strategies of dinoflagellates and ciliates in our model. Our results suggest that remineralization is largely driven by omnivorous ciliates and dinoflagellates, and highlight the importance of intraguild predation. We hypothesize that microzooplankton respond to changes in food quality in terms of nitrogen-to-carbon (N:C) ratios, rather than nitrogen-to-phosphorus (N:P) ratios, by allowing variations in their phosphorus-to-carbon (P:C) ratio. Our results point toward an important biogeochemical role of flexible microzooplankton stoichiometry

Description: Male secondary sexual traits are targets of inter- and/or intrasexual selection, but can vary due to a correlation with life-history traits or as by-product of adaptation to distinct environments. Trade-offs contributing to this variation may comprise conspicuousness towards conspecifics versus inconspicuousness towards predators, or between allocating resources into coloration versus the immune system. Here, we examine variation in expression of a carotenoid-based visual signal, anal-fin egg-spots, along a replicate environmental gradient in the haplochromine cichlid fish Astatotilapia burtoni. We quantified egg-spot number, area, and coloration; applied visual models to estimate the trait's conspicuousness when perceived against the surrounding tissue under natural conditions; and used the lymphocyte ratio as a measure for immune activity. We find that (i) males possess larger and more conspicuous egg-spots than females, which is likely explained by their function in sexual selection; (ii) riverine fish generally feature fewer but larger and/or more intensively colored egg-spots, which is probably to maintain signal efficiency in intraspecific interactions in long-wavelength shifted riverine light conditions; and (iii) egg-spot number and relative area correlate with immune defense, suggesting a trade-off in the allocation of carotenoids. Taken together, haplochromine egg-spots feature the potential to adapt to the respective underwater light environment, and are traded-off with investment into the immune system

Description: MSM60 – Kapstadt /Südafrika nach Montevideo/Uruguay 1. Wochenbericht - Maria S Merian MSM60

Description: Different studies on the position of the non-indigenous species Neogobius melanostomus within the coastal food web of the Pomeranian Bay (western Baltic) were performed, resulting in a quantitative and qualitative species list of prey organisms found in the stomachs of the invader and an estimation concerning the importance of round goby as prey for different resident predators. It seems that the colonization process is not fully completed yet, but the results reveal that the species is already established in the food web 16 years after the first observation within the study area. The results show that N. melanostomus feed upon a wide range of different resident organisms. While a direct predation effect on native fish species appears rather unlikely, indirect effects such as competition cannot yet be excluded. In addition, our results reveal an ontogenetic diet shift and that the round goby itself already serves as an important prey for piscivorous fish and seabirds. Finally, we formulate different hypotheses based on our results which will require further research.

Description: The active volcanic island Tristan da Cunha, located at the southwestern and youngest end of the Walvis Ridge - Tristan/Gough hotspot track, is believed to be the surface expression of a huge thermal mantle anomaly. While several criteria for the diagnosis of a classical hotspot track are met, the Tristan region also shows some peculiarities. Consequently it is vigorously debated if the active volcanism in this region is the expression of a deep mantle plume, or if it is caused by shallow plate tectonics and the interaction with the nearby Mid-Atlantic Ridge. Because of a lack of geophysical data in the study area, no model or assumption has been completely confirmed. We present the first amphibian P-wave finite-frequency travel time tomography of the Tristan da Cunha region, based on cross-correlated travel time residuals of teleseismic earthquakes recorded by 24 ocean-bottom seismometers. The data can be used to image a low velocity structure southwest of the island. The feature is cylindrical with a radius of ~ 100 km down to a depth of 250 km. We relate this structure to the origin of Tristan da Cunha and name it the Tristan conduit. Below 250 km the low velocity structure ramifies into narrow veins, each with a radius of ~ 50 km. Furthermore, we imaged a linkage between young seamounts southeast of Tristan da Cunha and the Tristan conduit.

Description: The ocean's potential to export carbon to depth partly depends on the fraction of primary production (PP) sinking out of the euphotic zone (i.e., the e-ratio). Measurements of PP and export flux are often performed simultaneously in the field, although there is a temporal delay between those parameters. Thus, resulting e-ratio estimates often incorrectly assume an instantaneous downward export of PP to export flux. Evaluating results from four mesocosm studies, we find that peaks in organic matter sedimentation lag chlorophyll a peaks by 2 to 15 days. We discuss the implications of these time lags (TLs) for current e-ratio estimates and evaluate potential controls of TL. Our analysis reveals a strong correlation between TL and the duration of chlorophyll a buildup, indicating a dependency of TL on plankton food web dynamics. This study is one step further toward time-corrected e-ratio estimates

Description: Diabetes mellitus is the most serious and prevalent metabolic disorders worldwide, complications of which can decrease significantly the quality of life and contribute to premature death. Resistance to insulin is a predominant pathophysiological factor of Type 2 diabetes (T2D). Protein tyrosine phosphatase 1B (PTP1B) is an important negative factor of insulin signal and a potent therapeutic target in T2D patients. This review highlights recent advances (2012–2015) in research related to the role of PTP1B in signal transduction processes implicated in pathophysiology of T2D, and novel PTP1B inhibitors with an emphasis on their chemical structures and modes of action.

Description: Tectonically induced changes in oceanic seaways had profound effects on global and regional climate during the Late Neogene. The constriction of the Central American Seaway reached a critical threshold during the early Pliocene ~4.8–4 million years (Ma) ago. Model simulations indicate the strengthening of the Atlantic Meridional Overturning Circulation (AMOC) with a signature warming response in the Northern Hemisphere and cooling in the Southern Hemisphere. Subsequently, between ~4–3 Ma, the constriction of the Indonesian Seaway impacted regional climate and might have accelerated the Northern Hemisphere Glaciation. We here present Pliocene Atlantic interhemispheric sea surface temperature and salinity gradients (deduced from foraminiferal Mg/Ca and stable oxygen isotopes, δ18O) in combination with a recently published benthic stable carbon isotope (δ13C) record from the southernmost extent of North Atlantic Deep Water to reconstruct gateway-related changes in the AMOC mode. After an early reduction of the AMOC at ~5.3 Ma, we show in agreement with model simulations of the impacts of Central American Seaway closure a strengthened AMOC with a global climate signature. During ~3.8–3 Ma, we suggest a weakening of the AMOC in line with the global cooling trend, with possible contributions from the constriction of the Indonesian Seaway.

Description: The cruise P474 was accomplished as part of the national research program “Entwicklung eines standardisierten Verfahrens zur flächendeckenden Erfassung und Beschreibung der sedimentologischen Eigenschaften und Prozesse auf der Meeresbodenoberfläche in der ausschliesslichen Wirtschaftszone (AWZ) von Nord- und Ostsee“ (SEDINO). The performed worked served to investigate the stability of sediment distribution patterns and the impact on benthic habitats in the North Sea.

Description: The effect of the environmental factors on permafrost has been studied. Three main factors, namely: the air temperature, the accumulated amounts of solid precipitation, and the vegetation dynamics, which govern the state of the frozen ground at time scales from few years to decades, are identified. The quantitative evaluation of their effect on the soil temperature variations and the construction of the conceptual model for predicting permafrost dynamics under the current and expected for the future climatic conditions, which accounts for the cumulative effect of major governing factors, have been carried out.

Description: MSM60 – Kapstadt /Südafrika nach Montevideo/Uruguay 3. Wochenbericht - Maria S Merian MSM60

Description: Studied samples of ikaite have been collected in the southern part of the Laptevs’ sea in 2008. XRD analysis data have shown that by destruction ikaite is transformed into calcite and waterite pha- ses. Isotopic composition of carbon (d13C) and oxygen (d18O) in the sample composed of the ikaite, calcite and vaterite mixture was –31.0 and –0.39 ‰, respectively, and after the complete destruction of ikaite it has become –29.0 and 0.67 ‰ VPDB, respectively. Calculated theoretical values of d18O in porous water, from which ikaite has formed in equilibrium conditions, vary from 4.0 to –2.8 ‰ VSMOW. It evidences the weak influence of the Lena river water upon formation of the studied sam- ple. The result of the balance calculations points that organic matter was the principal source of car- bon in ikaite (88—92 %), with supplementary supply from methane (8—12 %).

Description: International Ocean Discovery Program (IODP) Expedition 352 recovered a high-fidelity record of volcanism related to subduction initiation in the Bonin fore-arc. Two sites (U1440 and U1441) located in deep water nearer to the trench recovered basalts and related rocks; two sites (U1439 and U1442) located in shallower water further from the trench recovered boninites and related rocks. Drilling in both areas ended in dolerites inferred to be sheeted intrusive rocks. The basalts apparently erupted immediately after subduction initiation and have compositions similar to those of the most depleted basalts generated by rapid sea-floor spreading at mid-ocean ridges, with little or no slab input. Subsequent melting to generate boninites involved more depleted mantle and hotter and deeper subducted components as subduction progressed and volcanism migrated away from the trench. This volcanic sequence is akin to that recorded by many ophiolites, supporting a direct link between subduction initiation, fore-arc spreading, and ophiolite genesis.

Description: (22.01.-30.01.2017)

Description: The South American continent as we know it formed during the break-up of West Gondwana between 150 and 110 million years ago, when the South Atlantic Rift system evolved into the South Atlantic ocean. Using state-of-the-art global tectonic reconstructions in conjunction with numerical and analytical modelling, we investigate the geodynamics of rift systems as they evolve into an ocean basin. We find that rifts initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. In case of the split between South America and Africa, the divergence rate increased from initially 5 to 7 millimetres per year to over 40 millimetres per year within few million years. Intriguingly, abrupt rift acceleration did not only occur during the splitting of West Gondwana, but also during the separation of Australia and Antarctica, North America and Greenland, Africa and South America, in the North Atlantic or the South China Sea. We elucidate the underlying process by reproducing the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The mechanical models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength–velocity feedback similar to a rope that snaps when pulled apart. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time.

Description: The Atacama Fault System (AFS) is an active trench-parallel fault system, located in the forearc of N-Chile directly above the subduction zone interface. Due to its well-exposed position in the hyper arid forearc of N-Chile it is the perfect target to investigate the interaction between the deformation cycle in the overriding forearc and the subduction zone seismic cycle of the underlying megathrust. Although the AFS and large parts of the upper crust are devoid of any noteworthy seismicity or historically documented earthquakes, at least three M=7 earthquakes in the past 10 ky have been documented in the paleoseismological record, demonstrating the potential of large events in the future. We apply a two-fold approach to explore fault activation and reactivation patterns through time and to investigate the triggering potential of upper crustal faults. 1) A new methodology using high-resolution topographic data allows us to investigate the number of past earthquakes for any given segment of the fault system as well as the amount of vertical displacement of the last increment. This provides us with a detailed dataset of past earthquake rupture of upper plate faults which is potentially linked to large subduction zone earthquakes. 2) The IPOC Creepmeter array provides us with high-resolution time series of fault displacement accumulation for eleven stations along the four most active branches of the AFS.

Description: Die Aufgaben des Fraunhofer IGD im Rahmen des Projektes FLEXMOT waren die Entwicklung von Modulen für den Datenempfang, die Datenverwaltung und die Datenvisualisierung. Seit der gemeinsamen Festlegung durch alle Projektpartner im Konsortialmeeting am 29.10.2013 zeichnete das Fraunhofer IGD auch für das Gesamtprojektmanagement verantwortlich. Dies beinhaltete die organisatorischen und koordinierenden Aufgaben innerhalb des Konsortiums. Das Vorhaben wurde vor dem Hintergrund gestartet, dass durch die wachsende Expansion der Offshore-Exploration der Öl & Gas-Industrie, dem wachsenden gesellschaftlichen Umweltbewusstsein und Großunfällen wie dem Macondo-Blowout 2010 im Golf von Mexiko (Deep Horizon Unglück) offenbar wurde, wie groß der Bedarf für Umweltmonitoring-Technik ist, die besser und schneller einsetzbar, rekonfigurierbar und benutzbar sind (modulares Grundkonzept, geringe Rüstzeiten, lange Standzeiten) und zugleich größere Bereiche abdecken und eine schnelle Datenverfügbarkeit bieten. Daher initiierte der Hersteller von Gas-Sensorik Contros GmbH aus Kiel, der über entsprechendes Branchen-KnowHow und Kontakte im Öl&Gas-Bereich verfügte, zusammen mit den Unternehmen Oktopus GmbH und LEONI Special Cables GmbH und den Wissenschaftspartnern GEOMAR (Kiel) und Fraunhofer IGD (Rostock) das Projekt FlexMoT. Durch dieses Konsortium war sichergestellt, dass alle Bereiche (Mechanik, Sensorik, Prozess-KnowHow, Software für Datenmanagement und -auswertung und wissenschaftliche Unterwasser-Expertise) im Projekt vorhanden waren. Zudem war der anvisierte industrielle Markt für funktionierende und langzeittaugliche Monitoringinstrumente aufgrund der hohen Ölpreise sehr vielversprechend. Ziel war es, ein entsprechendes flexibles und modulares System zu entwickeln, welches die entscheidenden Schwächen bisheriger System umgeht und auch für den Einsatz durch nichtwissenschaftliche Anwender (Industriekunden) geeignet ist. Im Projekt sollte zum einen eine Erprobung der Entwicklungen auf ihre Unterwasser- und Einsatztauglichkeit hin stattfinden. Zum andere sollte die Funktionstüchtigkeit des Gesamtsystems nachgewiesen werden. Für diese Feldtests war es notwendig, mit einem geeigneten Schiff im angestrebten Einsatzumfeld, der Nordsee, und in typischen Wassertiefen der Kontinentalschelf-Offshore-Förderung zu testen. Das GEOMAR organisierte und stellte dafür das Forschungsschiff FS ALKOR und Schiffszeiten sowie wissenschaftliches Equipment für die Referenzmessungen zur Verfügung.

Description: Maria S. Merian MSM61 (Mindelo – Las Palmas) 18.02.2017 - 27.02.2017 Tropischer Ostatlantik