ALBERT

Description: RV Sonne cruise 206 started on the 31st of May in Caldera (Costa Rica) and ended there on the 18th of June 2010. An international group of 23 scientists and 2 guests from Costa Rica set out to perform geophysical, biogeochemical, and sedimentological investigations at and around a number of submarine cold seeps that are ubiquitous along this convergent continental margin. The cruise was predominantly conducted as a pre-site survey for IODP (proposal 633Full-2; Costa Rica Mounds) in order to fill existing gaps in the seismic record at two of the proposed drill locations. A 2D seismic survey was conducted running over the large-scale seamount subduction slide “Jaco Scarp” yielding a highly improved image of the structural pattern within the upper 1000 m of the sedimentary sequence. In addition, high-resolution 3D seismic data, roughly covering the uppermost 300 m, could be obtained in the Mound 11/12 area, which will allow for a detailed analysis of the internal structure of these mud volcano-like features and help to understand the complex relation to the upward directed material flow. Moreover, a total number of 36 sediment cores (TV-guided multicorer, gravity corer) were successfully retrieved from active cold seeps and submarine slides and a large number of sub-samples were taken for subsequent geochemical and microbiological analyses. Overall, all major tasks of this cruise could successfully be fulfilled and the results will help to further our understanding of mechanisms controlling fluid flow in the deep subsurface of active continental margins.

Description: The Kieler Wirkstoff-Zentrum KiWiZ (Centre for Marine Natural Products) at IFM-GEOMAR is investigating opportunities to use substances from microbial communties for medical and other applications. The new field of Marine Biotechnology is an emering area in Marine Sciences.

Description: Precise isotope analysis has developed to one of the most important tool in marine geochemistry. Accurate isotope fractionation is used for climate reconstructions for millions years back into the Earth’s history.

Description: The research project SO208 PLUMEFLUX (Propagation of Galápagos Plume Material in the Equatorial East Pacific) is funded by the German Ministry of Education and Research (BMBF) and focusses on seamounts on the Cocos Plate, formed at the East Pacific Rise but presently located off the coast of NW Costa Rica and Nicaragua (Leg 1), and on the Cocos-Nazca-Spreading Center(CNS; Leg 2). The studies conducted on cruise SO208 included multi-beam mapping, sediment echo sounding, hard rock sampling, as well as sedimentological and biological sampling. The major geological targets of Leg 1 were (1) to evaluate if the seamounts off northern Costa Rica and Nicaragua were formed by the Galápagos hotspot and thus to constrain the extent of influence by the Galápagos plume on the upper asthenosphere and lithosphere and (2) to constrain better the material input into the Central American subduction zone. Leg 2 aimed to sample profiles of the seafloor perpendicular to the CNS using the mobile drill Rockdrill 2 of the British Geological Survey, in order to reconstruct plume-ridge interaction in the past to complement morphological, petrological and geochemical studies carried out on previous cruises along the ridge axis (e.g. SO158). The integration of the results with existing data should contribute towards a better understanding of transport processes of plume material in the upper mantle and of the geodynamic evolution of the central East Pacific. The sedimentological studies carried out on both Legs of SO208 focussed on radiolarian assemblages. SO208 startet in Caldera/Costa Rica on July 15th, 2010, and ended in Guayaquil/Ecuador on August 29th, 2010. During Leg 1 nineteen seamounts on the Cocos Plate have been mapped and sampled. Within only 12 days at sea, a total of 41 stations(28 dredges, 2 TV grabs, and 11 multicorers) were carried out. Of these deployments, 23 recovered magmatic rocks, 15 volcaniclastics, and 13 Mn-Fe oxides. The samples comprise mainly pillow and sheet lavas, often with fresh glassy margins, and a wide spectrum of volcaniclastic rocks. Notably, we found several indications for explosive volcanic activity at water depths 〉 3,000 m. Due to a series of unfortunate circumstances beyond our control, the planned Rockdrill 2 deployment on Leg 2 had to be cancelled. Instead we mapped and collected samples via dredging from 60 localities along five profiles perpendicular to CNS. A total of 83 stations (76 dredges, 3 TVgrabs, and 4 multicorers) were carried out. Of these deployments, 59 recovered magmatic rocks, 3 volcaniclastics, 51 volcanic glass, and 6 Mn-Fe oxides, making this a successful cruise despite the Rockdrill problem. The first and most detailed profile (with 23 sampled localities) extended from the ridge axis to the north at ~92°W. The morphology shows alternating regions of abyssal ridges and valleys (possibly reflecting less plume input into the ridge) and thicker elevated bands commonly containing seamounts, some of which are tectonically deformed (possibly reflecting axial ridge type morphology and thus greater plume input into the ridge). The second profile was carried out at the shallowest part of the ridge axis, closest to the hotspot, just to the east of the 91° Transform Fault. The third profile extended 30 km north of the ridge (at ~89°30´W), where a formerly on-axis seamount has been split in half. We want to evaluate how far in the past the unique enriched geochemical anomaly associated with the seamount persisted in the past. Thirteen sites were successfully sampled along a fourth profile at 89°10’W, extending 35 km north and 35 km south of the CNS into crust up to 500,000 yrs old. This site was selected, because a major depleted geochemical anomaly exists at that location. A final short profile was carried out to the north and south and east (on the ridge axis) of a lava plateau at 88°20’W that represents an enriched anomaly along the ridge axis. The morphology of the area studied on Leg 2 strongly suggests that the intensity of interaction of the plume with the ridge has varied considerably over the last several hundred thousand years along the entire part of the ridge that we studied. Geochemical data should allow us to constrain better variations in plume-ridge interaction through time. Biological material was obtained successfully as macrofauna and as sediment samples containing meiofaunal organisms with the help of a geological chain bag dredge, sediment traps, a multicorer and a TV-grab. Macrofaunal organisms were recovered at 93 out of 124 stations, 37 stations revealed sediment samples. During the cruise, a total of 8,598 meiofaunal organisms were centrifuged out of about 45 kg of sediment and sorted to animal group. Foraminifera and Nematoda dominated the meiofauna, followed by Copepoda and at a lower abundance by Tardigrada, Kinorhyncha and Loricifera. We also discovered a highly diverse benthic macrofauna, mainly represented by Porifera, Bryozoa, Annelida, Brachiopoda and even a few monoplacophoran molluscs.

Description: El Niño-Southern Oscillation (ENSO) is the strongest natural climate phenomenon on timescales from months to a few years. Sucessfully modelling and subsequently forecasting ENSO is still a challenge although significant progess has been made during the past decades. IFM-GEOMAR scientists developed a new model which is currently being tested for ENSO applications.

Description: Marine scientists studying the seafloor always have to deal with the fact that the research vessel they are sailing with will be separated from the object they wish to study by several kilometers of water. Technological developments are helping IFM-GEOMAR scientists to overcome this problem and producing astounding results.

Description: Tectonic stresses lead to the deformation of the Earth’s crust and upper mantle. They are the driving force behind plate motion and mountain building, and they control earthquake distribution and intensity. These stresses can be measured from deformation microstructures of previously deeply buried rocks using paleo-piezometers. A new assessment of microstructural data from naturally deformed quartz-bearing rocks indicates that the mechanism of recrystallization fundamentally affects the piezometers. Our findings point out major inaccuracies of stress estimates published in the last 40 years, and it prepares the field for a new piezometer generation that will provide a significantly improved assessment of the stress states in lithospheric plates and plate boundaries.

Description: Changing environmental conditions, worldwide transport by commerical ships provide the basis for the increasing rates of marine invasions with substantial impact of marine ecosystems. Here we focus on the comb jelly Mnemiopsis leidyi one of the most prominent marine invaders. worldwide.

Description: Human-induced climate change is causing a warming of the surface ocean. Due to widely differing temperature sensitivities of key biological processes, this may have profound implications for marine food web interactions and the biogeochemical cycling of key elements such as carbon. Using a novel indoor-mesocosm approach, we show that rising sea surface temperature shifts the balance between photosynthetic production and respiratory consumption of organic carbon in a plankton community. This may weaken the ocean’s capacity to sequester atmospheric CO2, hence providing a positive feedback to anthropogenic climate change.

Description: Port calls: Saßnitz

Description: Kiel – Visby – Ventspils ‐ Kiel: 29. 05. – 21. 06. 2010 Cruise ALKOR 355 (AL‐355) was carried out within the framework of the EU FP‐7 project “HYPOX” (In situ monitoring of oxygen depletion in hypoxic ecosystems of coastal and open seas, and land‐locked water bodies). The scientific objectives focused on redox‐dependent nutrient and nitrogen cycles in the benthic boundary layer of the suboxic to anoxic Gotland Basin. The scientific party comprised of scientist from the IFM‐GEOMAR, Kiel (Germany). Main objectives were to study release rates and inventories of nutrients and nitrogen compounds under varying degrees of bottom water oxygenation in the anoxic to suboxic eastern Gotland Basin (central Baltic). Another goal was to quantify source/sink mechanisms of the benthic boundary layer for nitrogen species and nutrients under changing oxygen conditions to assess potential feedbacks on the upper mixed layer processes. In order to obtain these goal, we monitored the water column, sampled surface sediments and deployed several landers along a transect from oxygenated to suboxic and anoxic to sulfide benthic boundary layer conditions in the Latvian EEZ of the eastern Gotland Basin in a depth range from 49m to 235m.