ALBERT

Description: Cruise Report POS493 (AUV DeDAVE) – Canary Islands, January 26th to February 1st, 2016 - Test cruise for AUV “DeDAvE” around the Canary Islands

Description: Expedition M143 is a replacement for the originally scheduled expedition to the Marmara Sea to retrieve long term monitoring geodetic equipment. A short proposal to extend bathymetric mapping and imaging of active gas seepage in the Danube Delta region was approved and permission to operate in Romanian waters was successfully secured. Based on the results of mapping completed during the previous expedition M142 and other earlier missions to the same region, a set of survey lines and imaging targets were defined for M143. Objectives for expedition M143 were twofold and include the of use a dedicated 38 kHz single beam echo sounder installed in the moonpool of the research vessel METEOR for gas emission quantification and to complete bathymetric mapping for the detection of sub marine slope failures and mass transport deposits in associated with gas seepage and the occurrence of gas hydrates. During the active data acquisition phase of expedition M143 (December 12 to December 17, 2017) three sub-regions for gas flare imaging were visited (Lander Site from M142, S2 channel eastern flank, and shallow shelf region). A total of 1,189 line kilometers (642 nautical miles) of data were acquired. Out of these, a total of 238 km were acquired using the 38 kHz EK80 and EM710 (and partially EM122) multibeam data. Also, a full calibration of the 38 kHz echo sounder was accomplished and sound velocity data were recorded at the Lander and shallow shelf region survey sites. Bathymetric mapping using both EM systems EM122 and EM710 combined with the PARASOUND sub bottom profiler was completed in two main regions filling in data gaps in the existing multibeam coverage prior to M143. The first region was visited during the initial transit to the study region (December 14) around the region of the S2 channel head in water depths ~120 m. Here, a set of six parallel lines were acquired, totaling 70 km line lengths and covering an area of 11.5 square kilometers. The second region was in the eastern part of the Danube delta region, close to the Ukrainian border. In total 805 line kilometers and 472 square kilometers of multibeam data were acquired.

Description: In the marine environment elevated electrical conductivities may be caused by sulfide mineralizations within the seafloor as well as hot saline pore fluids. Such conductive targets may be studied with suitable electromagnetic systems like the novel coil-system MARTEMIS1, which we previously used to investigate a known zone of sediment covered mineralization at the Palinuro Seamount (cruises POS483 & POS509) and in the vicinity of the TAG hydrothermal mound at the Mid Atlantic Ridge (cruise JC138). Both the Palinuro site as well as the sites in the vicinity of the TAG hydrothermal mound (Shinkai, Double Mound, MIR) are hydrothermally inactive and, thus, allowed to study, how the responses of an inductive EM system is influenced and shaped by mineralizations within the seafloor without having to consider the effect of of heated pore fluids. In the interpretation of the collected data at these inactive sites we learned that the MARTEMIS system is able to detect conductivity anomalies in the vicinity of mineralizations. (...)

Description: The majority of M〉8.5 active plate boundary earthquakes has hypocenters located beneath the oceans in subduction zones. Post-hoc analysis shows that most of the surface deformation related to co-seismic stress release takes place on the seafloor, in many cases unleashing major tsunamis. The structure and morphology of the seafloor and shallow subbottom thus stores crucial information on sub-seafloor processes, such as permanent deformation by seismic slip or aseismic creep within the overriding plate and earthquake and tsunami generation. We have mapped the seafloor seaward of the Northern Chilean coast between about 19°S and 22°S down to the Northern Chile deep sea trench, using the ship-based Multibeam Echosounder EM122, Parasound, and AUV (autonomous underwater vehicle) – in selected subareas - at sufficient resolution to identify active tectonic fault structures and submarine mass wasting structures, to quantitatively assess young and active deformation of the overriding plate in the area, and quantify the extent of recent catastrophic downslope mass movements of sediment. Furthermore, the investigations serve as a site survey for the deployment of the GeoSEA seafloor geodetic array, to be installed immediately after completion of this cruise. The investigations were made timely by the 1st April 2014 Pisagua M=8.2 earthquake, that ruptured the plate interface in the northern part of the area of investigation. The central and southern parts are located in the last remaining locked seimotectonic segment along the Chilean active margin. In addition to providing the first data base for geomorphological and tectonic interpretation of geo-processes at the seafloor, the bathymetric mapping done during SO244 Leg 1 will provide an important data reference for possible post-earthquake surveys once this seismotectonic segment will have broken in the future.

Description: At present, investigations of submarine massive sulfides (SMS) are mostly limited to active systems due to the available methods and technologies, which rely on the detection of water column anomalies (tempera - ture or chemical tracers) and the study of seafloor's morphology. They fail to detect sites where hydrothermal activity has ceased and former landmarks such as black smokers have been eroded or are covered by sediments. During RV Poseidon cruises POS483 (“ElectroPal”) and POS484 (”MARSITE”) we have successfully collected EM and airgun seismic data over an inactive and sediment covered SMS site at Palinuro, which had previously been found by chance in 1986 and was drilled to 5m depth during research cruise M73/2. EM measurements, carried out with the novel system MARTEMIS1, not only showed high conductivities in the vicinity of the SMS deposit, but also revealed a second anomaly, possibly a zone of buried mineralization at greater depth. During cruise POS509 previous measurements were continued and extended to get a full areal coverage of the structure to fully delineate and characterize the SMS sites. EM investigations were accompanied by measurements of the ambient electrical field (→ selfpotential (SP)) and additional geophysical (heat probe) and geological (gravity core) measurements for ground truthing and further structural insight. The combination of experiments proved to be convenient in terms of handling on the ship, as EM experiments on the one hand and measurements with heat probe and gravity coring on the other hand were performed in an alternating manner each other day. This alternating style of experiments gave each method time for adjust - ments and repairs as well as time to take a first look at results so that following investigations could be directly aimed at a specific target. As an example, an anomaly detected in the SP measurements in the NNW was used to guide the last gravity coring, which then found sulfide muds in an area where sulfides were previously not expected.

Description: Poseidon cruise 518 (leg 1 and 2) took place in the framework of the Horizon 2020 project STEMM-CCS of the EU. The project’s main goal is to develop and test strategies and technologies for the monitoring of subseafloor CO2 storage operations. In this context a small research-scale CO2 gas release experiment is planned for 2019 in the vicinity of the Goldeneye platform located in the British EEZ (central North Sea). Cruise POS518 aimed at collecting necessary oceanographic and biogeochemical baseline data for this release experiment. During Leg 1 ROV PHOCA was used to deploy MPI’s tool for high-precision measurements of O2, CO2 and pH in the bottom water at Goldeneye. In addition, ROV push cores and gravity cores were collected in the area for sediment biogeochemical analyses, and video-CTD casts were conducted to study the water column chemistry. The stereo-camera system and a horizontally looking multibeam echosounder, both, for determining gas bubble emissions at the seafloor were deployed at the Figge Maar blowout crater in the German Bight. Investigations were complemented by hydroacoustic surveys detecting gas bubble leakages at several abandoned wells in the North Sea as well as the Figge Maar. Surface water alkalinity as well as CH4, CO2, and water partial pressures in the air above the sea surface were measured continuously during the cruise. During Leg 2 three different benthic lander systems were deployed to obtain baseline data of oceanographic and biogeochemical parameters for a small research-scale CO2 gas release experiment planned for 2019. The first lander was equipped with an acoustic Doppler current profiler (ADCP), a CTD and an O2 optode. It was deployed for 6 days close to Goldeneye to obtain high resolution data which can be linked to the long-term measurements of the NOC-Lander. This lander is equipped with a suite of sensors to monitor temperature, conductivity, pressure, current speed and direction, hydro-acoustic, pH, pCO2, O2 and nutrients over a period of about 10 months with popup telemetry units for data transmission via IRIDIUM satellite telemetry every 3 months. Two short-term deployments of the Biogeochemical Observatory (BIGO) were conducted to study the molar ratio between oxygen and CO2-fluxes at the seafloor. Sediment cores obtained by gravity and multi corer were collected for sediment biogeochemical analyses and video-CTD casts were used to study the chemistry of the water column.

Description: R/V SONNE cruise SO-233 WALVIS II conducted geological, morphological, and biological studies in the area of the aseismic Walvis Ridge and the adjacent ocean floor (South Atlantic). The Walvis Ridge is a textbook example of a hotspot track connected to a continental flood basalt province and represents the Atlantic “type locality” for the enriched mantle one (EM-I) geochemical endmember in intraplate volcanic rocks. Despite its importance in the global hotspot reference frame, endmember geochemical composition, and uncertainties in its formation and evolution, basement sampling of the Walvis Ridge remained poor to date, in particular along its easternmost 1500 km. The geological studies carried out during SO-233 therefore aimed for extensive multi-beam mapping using a SIMRAD EM 120 echo-sounding system, sediment echo-sounding using a ATLAS PARASOUND sub-bottom profiling system, and hard rock sampling by dredging and TV-grab of the Walvis Ridge and associated features. The major targets of the WALVIS II project are (1) to test for age progressive volcanism along the ridge, (2) to differentiate between classical hotspot and plate fracturing models for its formation, and (3) to constrain the origin, temporal and spatial evolution of melting conditions and source compositions (in particular regarding the EM-I endmember and proposed zonation models of mantle plumes). The biology program conducted on SO-233 comprised sampling of benthic organisms and meiofauna using a TV-multi-corer, a TV-grab, sediment traps installed in the geological dredges, and by collecting marine invertebrates from the hard rocks yielded by dredging. The biological investigations of the WALVIS II project intend to describe the benthic diversity of deep-sea invertebrates of the Walvis Ridge and will help to identify proxies of species connectivity and dispersal between the Walvis Ridge and neighboring ridge like structures (e.g. Agulhas Ridge). Another objective is to test whether connectivity of benthic communities in the Angola and Cape Basins is interrupted by the Walvis Ridge. SO-233 multi-beam mapping revealed that the southern bifurcated section of the Walvis Ridge appears to have formed through the coalescence of former volcanic islands. The new bathymetric data also yielded several evidence for large-scale extensional tectonic movements which are most likely related to the separation of the Walvis Ridge and Rio Grande Rise that were rifted apart by the mid Atlantic Ridge. Seventy-one dredge hauls have been conducted during SO-233. Of these, 28 delivered massive lavas, 24 volcaniclastic rocks including breccias containing lava fragments, 22 sedimentary rocks, and 11 Mn-Fe-oxide crusts and nodules. The volcanic rocks comprise a broad variety of lavas as well as epiclastic, hydroclastic, and pyroclastic rocks. Carbonates dominate among the non-volcanic rocks, many of them represent relicts of fossil coral reefs. Despite technical problems with the EM 120 system and difficult weather and seafloor conditions occasionally constraining rock sampling, SO-233 achieved its major goals, i.e. bathymetric mapping and representative hard rock sampling of all major geomorphological units of the Walvis Ridge and of associated features. The set of rock samples recovered during SO-233 represents the by far most detailed sampling of the Walvis Ridge to date. Out of 91 collecting stations, 80 stations yielded the total amount of 80 kg of sediment from sediment traps in the geological dredges, TV-multi-corer tubes and TV-grab. At 44 stations we could collect macrofaunal organisms, partly in large quantities. Ninety specimens of living brachiopods representing 6 genera were found at all depths and will mainly be used for molecular diversity studies. The remaining living macrofauna was largely composed of sponges, octocorals, some deep water hexacorals, molluscs, polychaetes, bryozoans, cirriped crustaceans and a few isopods and amphipods, mainly occurring in small numbers and medium diversity. The most spectacular finding was a fossil cold water reef mound community, which shows similarities in species composition to North Atlantic cold water reefs and proofs the influence of Antarctic benthos communities on the Walvis Ridge fauna mediated by northbound cold water currents. The samples represent the most diverse collection of benthos organisms ever retrieved from the Walvis Ridge region.

Description: R/V POSEIDON cruise P457 aimed further development of detailed marine tephrochronology of Iceland by sediment coring in order to improve our knowledge of the spatio-temporal evolution of Icelandic volcanism and related hazards. In addition, the marine record contains paleoclimatic information, which may relate recurrent glacier advances and land degradation periods to ocean and atmospheric circulation changes. A minor sub-project should contribute to a better understanding of Surtsey volcanism by investigations of marine Surtsey tephra. P457 conducted extensive sediment echosounding (11 surveys with a total length of c. 425 nm) in order to identify undisturbed sediment sequences for coring. At 20 appropriate sites, P457 deployed gravity and/or gaint box corers to recover ultra-high resolution sediment cores from 〈 100 m to ~1,600 m water depth at the south-western, southern and eastern sectors of the Icelandic shelf and slope. Of these deployments, 9 gravity corers yielded altogether 59.5 m core recovery and 11 box corers recovered surface sediment samples. Additionally 7 CTD/rosette water sampling stations have been performed at shallow sites close to Iceland and at deep sites further offshore in order to determine the REE distributions and the Nd and Hf isotope compositions of the sea water. No equipment was lost or significantly damaged. Cruise P457 was particularly successful in the working areas southwest and south of Iceland but failed to recover long sediment cores in the eastern working areas and at Surtsey. Sand, clayey silt, clayey sandy silt, sandy clayey silt, and volcanic ashes are the dominant lithologies in the P457 sediment cores. Preliminary studies of selected sedimentary records along the Iceland margin from ca. 24°W to 12°W on both sides of Reykjanes Ridge suggest that a correlation of these cores is possible, implying that sedimentary records are undisturbed and of high quality. Notably, distinct volcanic ash layers can apparently be traced in the P457 cores across the working area. Preliminary age models of selected cores show that the sedimentation rates around Iceland are low with only a thin Holocene. Sediment records cover approximately 120.000 years at most.

Description: Cruise P453 & P458 with R/V POSEIDON aim to conduct 3D wide-angle ocean bottom recording (OBR) data during the acquisition of 3D multichannel seismic (MCS) reflection data (D. Sawyer, Rice University & T.J. Reston, Birmingham) and to analyze and interpret a highresolution densely sampled 2D OBR wide-angle profile. The primary goal of the wide-angle data will be to provide an accurate and detailed 3D P-wave velocity model for the 3D reflection data. Particularly the densely sampled 2D profile will help to determine the degree of thinning within the crust and the degree of serpentinisation of the uppermost mantle. The collection of 3D MCS data gives the unique opportunity to obtain densely sampled water column reflection data and to analyze spatial and temporal (4D) variations of the internal wave field which will yield new understanding and insights into water mass mixing processes offshore west Iberia. Contemporaneously hydrographic data will be collected to calibrate and analyze the oceanic thermohaline structures originating from the interaction between Atlantic waters and the Mediterranean Sea Outflow.

Description: The R/V SONNE expedition SO265 is the central activity of the research project "Shatsky Evolution" that is funded by the Federal Ministry of Education and Research and conducted by the GEOMAR Helmholtz Centre for Ocean Research Kiel in collaboration with international partners. The goal of the project is the investigation of the late stage evolution of Shatsky Rise, a vast, submarine volcanic plateau (Large Igneous Province) in the northwest Pacific. In particular, the project aims to investigate the transition from plateau volcanism (the main body of Shatsky Rise) to postulated hotspot track volcanism (Papanin Ridge and/or Ojin Rise seamounts). Applied methods included bathymetric mapping with the ship's own multi-beam echosounder (KONGSBERG EM 122), subbottom profiling (ATLAS PARASOUND DS P70), and rock sampling with chain bag dredges. The main working areas were the Papanin Ridge (the northern extension of Shatsky Rise) and the Ojin Rise Seamount Province (a broad belt of individual seamounts to the east of Shatsky Rise). Dredge hauls were conducted between ~36°N and ~44°N and ~163°E and ~170°E covering the entire geographic extent of both working areas. A third working area, the northern part of Shatsky Rise dominated by its Shirshov Massif, served as a contingency area and only a few dredge hauls were conducted there. In addition, sampling was successfully executed at Hokkaido Trough (45°06'N, 162°27'E), located ~320 km northwest of Papanin Ridge. A total of 72 dredge hauls in average water depths of 4,640 m were carried out during SO265. Of these, 49 (= 68%) delivered in situ volcanic rocks samples. No deployed equipment was lost or damaged. Post-cruise investigations at GEOMAR and cooperating institutions will include volcanological/petrological, geochronological, and geochemical studies. Furthermore, macro-benthic organisms were collected from the surfaces of the recovered rocks to study the diversity of deep-see invertebrates, and sediment sampling (by small sediment traps installed in the dredges) was conducted for meiofauna studies.

Description: The R/V SONNE expedition SO-249 is part of the research project BERING, conducted in the framework of the Russian-German Agreement on Marine and Polar Research and in close cooperation with U.S. American colleagues. The overarching goal of BERING is to elucidate the magmatic and tectonic evolution of the Bering Sea and its margins over the past ≥50 m.y. In particular, BERING investigates the physical and chemical conditions that control the development of subduction zones, including subduction initiation, evolution of mature arc systems, and the impact of subduction volcanism on the environment. R/V SONNE cruise SO- 249 BERING conducted geological, morphological, and biological studies in the in western the Aleutians, the Pacific seafloor subducting beneath the Aleutians and northern Kamchatka, and in the western Bering Sea. Besides extensive multi-beam mapping and sediment echo-sounder profiling, total of 150 dredge hauls have been conducted on the two legs of cruise SO-249. Of these, 91 delivered massive magmatic and/or metamorphic rocks, 34 volcaniclastic rocks including breccias containing lava fragments, 64 sedimentary rocks, and 19 Mn-Fe-Oxide crusts and nodules. No equipment was lost or seriously damaged. SO-249 achieved its major goals and the SO-249 sample set represents the most detailed sampling of the working areas to date. The on shore work program at Russian, German, and U.S.-American institutions includes geochronological, petrological and geochemical studies on igneous samples obtained during the cruise. The results of BERING will be integrated with those of previous campaigns (e.g. KOMEX, KALMAR), and work carried out within the World Oceans and GeoPRISMS initiatives. The main goal of biological sampling was to survey the benthic biodiversity in the study area. In addition, fresh specimens pertaining to specific taxa (Cnidaria, Brachiopoda, Cephalopoda, Echinodermata) were collected to supplement ongoing research projects. Of the 150 dredges taken, 150 (100%) contained sediment and 112 (74.7%) contained macrofauna. In addition to the 150 sediment samples, almost 1,500 single benthic, benthopelagic, and pelagic macrofaunal organisms were obtained. The majority of the objectives of biological sampling were reached, in particular with regard to obtaining fresh tissue for immunohistochemical, genomic, and transcriptomic analysis from various brachiopod and ophiuroid species.