ALBERT

Description: High acoustic seafloor-backscatter signals characterize hundreds of patches of methane-derived authigenic carbonates and chemosynthetic communities associated with hydrocarbon seepage on the Nile Deep Sea Fan (NDSF) in the Eastern Mediterranean Sea. During a high-resolution ship-based multibeam survey covering a ~ 225 km**2 large seafloor area in the Central Province of the NDSF we identified 163 high-backscatter patches at water depths between 1500 and 1800 m, and investigated the source, composition, turnover, flux and fate of emitted hydrocarbons. Systematic Parasound single beam echosounder surveys of the water column showed hydroacoustic anomalies (flares), indicative of gas bubble streams, above 8% of the high-backscatter patches. In echosounder records flares disappeared in the water column close to the upper limit of the gas hydrate stability zone located at about 1350 m water depth due to decomposition of gas hydrate skins and subsequent gas dissolution. Visual inspection of three high-backscatter patches demonstrated that sediment cementation has led to the formation of continuous flat pavements of authigenic carbonates typically 100 to 300 m in diameter. Volume estimates, considering results from high-resolution autonomous underwater vehicle (AUV)-based multibeam mapping, were used to calculate the amount of carbonate-bound carbon stored in these slabs. Additionally, the flux of methane bubbles emitted at one high-backscatter patch was estimated (0.23 to 2.3 × 10**6 mol a**-1) by combined AUV flare mapping with visual observations by remotely operated vehicle (ROV). Another high-backscatter patch characterized by single carbonate pieces, which were widely distributed and interspaced with sediments inhabited by thiotrophic, chemosynthetic organisms, was investigated using in situ measurements with a benthic chamber and ex situ sediment core incubation and allowed for estimates of the methane consumption (0.1 to 1 × 10**6 mol a**-1) and dissolved methane flux (2 to 48 × 10**6 mol a**-1). Our comparison of dissolved and gaseous methane fluxes as well as methane-derived carbonate reservoirs demonstrates the need for quantitative assessment of these different methane escape routes and their interaction with the geo-, bio-, and hydrosphere at cold seeps.

Description: Bathymetry based on data recorded during M111 between 10.10.2014 and 01.11.2014 in the eastern Mediterranean Sea. The aim of the cruise was to quantify the deep geometry and architecture of the Calabria subduction zone and Ionian Sea lithosphere and to shed light on the nature of the Ionian Sea with OBS/OBH and deep sea seismics. Additionally the M111 cruise formed the core of an ambitious investigation covering the Ionian Sea and island of Sicily. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de) as responsible party for bathymetry. Description of processed data sources: During the cruise M111 the Kongsberg EM122 multibeam echosounder with a nominal sounding frequency of 12 kHz was utilized. 288 beams (and up to 864 soundings in equidistant and dual swath mode) are formed for each ping with a 1°(Tx)/2°(Rx) footprint while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult https://www.km.kongsberg.com/. The EM122 was recording during the deployment of the OBH/OBS, during seismic surveys and during transits. Responsible person during this cruise / PI: Ingo Klaucke (iklaucke@geomar.de). Description of data processing: Postprocessing and products were conducted by the Seafloor-Imaging & Mapping group of MARUM, responsible person: Paul Wintersteller (seafloor-imaging@marum.de). The open source software MB-System suite (Caress, D.W., and D.N. Chayes, MB-System Version 5.5, open source software distributed from the MBARI and L-DEO web sites, 2000-2012.) was utilized for this purpose. A tide correction was applied, based on the Oregon State University (OSU) tidal prediction software (OTPS) that is retrievable through MB-System. The CTD measurements taken during the M111 cruise were sufficient to represent the changes in the sound velocity throughout the study area. Further roll, pitch and heave corrections were not applied for the M111 data. Bathymetric data has been manually cleaned for existing artefacts with mbeditviz. NetCDF (GMT) grids of the product and the statistics were created using mbgrid. No total propagated uncertainty (TPU) has been calculated to gather vertical or horizontal accuracy. The currently published bathymetric grid of the cruise has a resolution of 70 m. A higher resolution is, at least partly, achievable. The grid extended with _num represents a raster dataset with the statistical number of beams/depths taken into account to create the depth of the cell. The extended _sd-grid contains the standard deviation for each cell. All grids produced are retrievable through the PANGAEA database (www.pangaea.de). Chief Scientist: H. Kopp hkopp@geomar.de CR: https://www.tib.eu/de/suchen/id/awi%3Adoi~10.2312%252Fcr_m111/ CSR: http://www.bsh.de/aktdat/dod/fahrtergebnis/2014/20140277.htm A special thanks goes to the PIs and watch keeper of the hydroacoustic systems during M111: Marzia Rovere, Ingo Klaucke, Anne Krabbenhoeft, Marc-André Gutscher

Description: Bathymetry data based on data recorded during M112 between 06.11.2014 and 15.12.2014 and during POS499 between 04.05.2016 and 22.05.2016 in the Mediterranean Sea. The aim of the cruises was to investigate in mud volcanoes of the Calabrian Arc in Italian waters, where 54 potential mud volcanoes have been documented while it remained unclear whether they are still active or not. Therefore, the bathymetric surveys were accompanied with investigations in the water column. Several sound velocity profiles (SVPs) were taken to correct the bathymetry. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de ) as responsible party for bathymetry post-processing and its products. Description of processed data sources at M112: During the cruise M112 the Kongsberg EM122 multibeam echosounder with a nominal sounding frequency of 12 kHz was utilized. 288 beams (and up to 864 soundings in equidistant and dual swath mode) are formed for each ping with a 1°(Tx)/2°(Rx) footprint while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult https://www.km.kongsberg.com/. The EM122 was recording constantly within the permitted areas, either designated to bathymetry surveys or flare imaging-surveys. Responsible person during this cruise / PI: Paul Wintersteller (pwintersteller@marum.de ) and Christian Ferreira (cferreira@marum.de ). Description of processed data sources during POS499: During the RV POSEIDON cruise POS499 the ELAC SB3050 multibeam echo sounder with a nominal sounding frequency of 50 kHz was utilized. 384 beams are formed for each ping while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult http://www.mdsys.co.kr/down/ELAC/SB_3050.pdf. During the POS499 cruise the swath - width has been set to AUTO mode and was commonly observed at around 80°. This given swath ‐ width refers to a coverage of about 1.6 times the water ‐depth and reduces the max. number of beams collected per ping to less than 240. Most of the time the multi‐ping mode has been used with a receiver reception gain value of 45dB. The recorded bathymetry covers in total 880 km and the mapped area is based on the bathymetry results from the M111 & M112 cruises. Responsible person for hydroacoustics during this cruise / PI: Paul Wintersteller (pwintersteller@marum.de ) Description of data processing : Postprocessing and products were conducted by the Seafloor-Imaging & Mapping group of MARUM/FB5, responsible person: Paul Wintersteller (seafloor-imaging@marum.de ). The open source software MB-system suite (Caress, D.W., and D.N. Chayes, MB-System Version 5, Open source software distributed from the MBARI and L-DEO web sites, 2000-2012.) was utilized for this purpose. A tide correction was applied, based on the Oregon State University (OSU) tidal prediction software (OTPS) that is retrievable through MB-System. Tidal changes in the Mediterranean Sea are up to max. 1m. CTD measurements were taken during the M112 and POS499 cruise, and these were sufficient to represent the changes in the sound velocity throughout the study area. Further pitch and heave corrections were not applied for the M112 and POS499 data though a roll off-set of -0.46° was applied for the POS499 data (mbset). Bathymetric data has been manually cleaned for existing artefacts with mbeditviz. NetCDF (GMT) grids of the product and the statistics were created using mbgrid. The currently published merged bathymetric grids of the cruise have a resolution of 30 m. A higher resolution is, at least partly, achievable. The grid extended with _num represents a raster dataset with the statistical number of beams/depths taken into account to create the depth of the cell. The extended _sd -grid contains the standard deviation for each cell. All grids produced are retrievable through the PANGAEA database (www.pangaea.de).

Description: Bathymetry data based on Multibeam echosounder SB3050 (MBES) was recorded during RV POSEIDON cruise POS462 between 28.10.2013 and 21.11.2013 in the Eastern Mediterranean Sea. The prime objective of the cruise was the investigation of the 'Anaximander Mountains' south of Turkey and therefore to decipher key processes of mud volcanoes, which led to the emission of gas hydrates in shallow marine sediments. During 8 AUV and several MBES surveys, four mud volcanoes were mapped. The detailed mapping of these mud volcanoes and identification of gas hydrate emissions were the main research interests of the hydroacoustic group on board. Additionally samples of the mud volcanoes were taken using a gravity corer and heat/flow measurements were done. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the RV POSEIDON cruise POS462 the ship-mounted ELAC SB3050 multibeam echosounder with a nominal sounding frequency of 50 kHz was utilized. A maximum of 384 beams with a 1.5°(TX)/2°(RX) footprint are formed for each ping while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult http://www.mdsys.co.kr/down/ELAC/SB_3050.pdf. A maximum range of 2000 was achieved, which caused limitations of the mapped area. Due to static beam positions and angles of the ELAC system the number of beams was reduced according to the depth. In shallower parts a maximum of 160/180 beams were produced. In comparison, in deeper parts (1800/2000m), these numbers were reduced by 40 beams. The Hydrostar software by ELAC was used to gather data. Problems with the navigation sensor and motion sensor CODA F180 were reported (further information can be found in the cruise report). Responsible person for hydroacoustic during this cruise / PI: Christian dos Santos Ferreira (cferrei-ra@marum.de) Chief Scientist: Gerhard Bohrmann (gbohrmann@marum.de) CR: http://elib.suub.uni-bremen.de/edocs/00103551-1.pdf CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2013/20130095.htm A special thanks goes to the watchkeeper: Ammar Aljuhne

Description: Bathymetry data based on Multibeam echosounder SB3050 (MBES) was recorded during RV POSEIDON cruise POS462 between 28.10.2013 and 21.11.2013 in the Eastern Mediterranean Sea. The prime objective of the cruise was the investigation of the 'Anaximander Mountains' south of Turkey and therefore to decipher key processes of mud volcanoes, which led to the emission of gas hydrates in shallow marine sediments. During 8 AUV and several MBES surveys, four mud volcanoes were mapped. The detailed mapping of these mud volcanoes and identification of gas hydrate emissions were the main research interests of the hydroacoustic group on board. Additionally samples of the mud volcanoes were taken using a gravity corer and heat/flow measurements were done. CI Citation: Paul Wintersteller (seafloor-imaging@marum.de as responsible party for bathymetry raw data ingest and approval. Description of the data source: During the RV POSEIDON cruise POS460 the ship-mounted ELAC SB3050 multibeam echosounder with a nominal sounding frequency of 50 kHz was utilized. A maximum of 384 beams with a 1.5°(TX)/2°(RX) footprint are formed for each ping while the seafloor is detected using amplitude and phase information for each beam sounding. For further information consult http://www.mdsys.co.kr/down/ELAC/SB_3050.pdf. A maximum range of 2000 was achieved, which caused limitations of the mapped area. Due to static beam positions and angles of the ELAC system the number of beams was reduced according to the depth. In shallower parts a maximum of 160/180 beams were produced. In comparison, in deeper parts (1800/2000m), these numbers were reduced by 40 beams. The Hydrostar software by ELAC was used to gather data. Problems with the navigation sensor and motion sensor CODA F180 were reported (further information can be found in the cruise report). Responsible person for hydroacoustic during this cruise / PI: Christian dos Santos Ferreira (cferreira@marum.de) Description of data processing: Postprocessing and products were conducted by the Seafloor-Imaging & Mapping group of MARUM/FB5, responsible person: Paul Wintersteller (seafloor-imaging@marum.de). The open source software MB-system suite (Caress, D.W., and D.N. Chayes, MB-System Version 5.4., Open source software distributed from the MBARI and L-DEO web sites, 2000-2012.) was utilized for this purpose. No tide correction was applied. Five CTD measurements were taken during the POS462 cruise, and these were sufficient to represent the changes in the sound velocity throughout the study area. Further pitch and heave corrections were not applied for the POS462 data though a roll off-set of 1.5° was applied (mbset). Bathymetric data has been manually cleaned for existing artefacts with mbeditviz. NetCDF (GMT) grids of the product and the statistics were created using mbgrid. No total propagated uncertainty (TPU) has been calculated to gather vertical or horizontal accuracy. The currently published bathymetric grid of the cruise has a resolution of 30 m. The grid extended with _num represents a raster dataset with the statistical number of beams/depths taken into account to create the depth of the cell. The extended _sd -grid contains the standard deviation for each cell. All grids produced are retrievable through the PANGAEA database (www.pangaea.de). Chief Scientist: Gerhard Bohrmann (gbohrmann@marum.de) CR: http://elib.suub.uni-bremen.de/edocs/00103551-1.pdf CSR: https://www2.bsh.de/aktdat/dod/fahrtergebnis/2013/20130095.htm Bathymetric raw-dataset published: not yet A special thanks goes to the watchkeeper: Ammar Aljuhne, Miriam Römer

Description: We are providing records of Globorotalia crassaformis as a new late Quaternary biostratigraphic marker for the southeastern Brazilian margin.

Description: High-frequency data collected continuously over a multiyear time frame are required for investigating the various agents that drive ecological and hydrodynamic processes in estuaries. Here, we present water quality and current in-situ observations from a fixed monitoring station operating from 2008 to 2014 in the lower Guadiana Estuary, southern Portugal (37°11.30' N, 7°24.67' W). The data were recorded by a multi-parametric probe providing hourly records (temperature, salinity, chlorophyll, dissolved oxygen, turbidity, and pH) at a water depth of ~1 m, and by a bottom-mounted acoustic Doppler current profiler measuring the pressure, near-bottom temperature, and flow velocity through the water column every 15 min. The time-series data, in particular the probe ones, present substantial gaps arising from equipment failure and maintenance, which are ineluctable with this type of observations in harsh environments. However, prolonged (months-long) periods of multi-parametric observations during contrasted external forcing conditions are available. The raw data are reported together with flags indicating the quality status of each record. River discharge data from two hydrographic stations located near the estuary head are also provided to support data analysis and interpretation.

Description: This data collection belongs to an article in preparation: Structure and composition of the ichthyofauna of the Praquiquara igarapé, Atlantic Northeast Atlantic Hydrographic Region of Brazil.

Description: Western boundary upwelling systems such as those found in the southeastern Brazilian margin (SBM) are promoted by special atmospheric and oceanographic interactions with topography of the coastline. In order to investigate the evolution of the upwelling system in SBM over the past 110 kyr, the abundance of Globigerina bulloides (a planktonic foraminiferal species typically associated with upwelling waters) from two marine cores was combined with estimates of upper water thermal structure derived from Modern Analog Technique based on planktonic foraminifera. High abundances (up to 35%) of large specimens of G. bulloides (〉= 250 µm) associated with cooling subsurface waters reveal the occurrence of an intense coastal upwelling system between 110 kyr and 88 kyr. Changes in coastline orientation due to lower sea level stand (20-70 m lower than today) and a longer season of vigorous Brazil Current (BC) and prevailing northeasterly winds maintained permanently the cold and nutrient-rich South Atlantic Central Waters (SACW) over the shelf promoting the strongest upwelling system of the Brazilian coast over the past 110 kyr. At 88 kyr, a sharp reduction of 14% in abundance of G. bulloides and a 2.6 °C warming of the water column indicates an abrupt weakening of the coastal upwelling, probably caused by a disturbance in SACW formation. During the last glaciation, longer current winter-like conditions of prevailing southwesterly winds and a weakened Brazil Current suppressed the upwelling system in SBM. At this time, constant and relatively high abundance of G. bulloides (up to 10%) suggest that the coastal upwelling was restricted to a short period of months year-round, when the BC and northeasterly winds were relatively vigorous despite the glacial context. The predominance of warm and oligotrophic Tropical Waters due to the shutdown of coastal upwelling in northern SBM was inferred for the last 20 kyr. Despite vigorous northeasterly winds and BC strength, high sea level stand during the Holocene submersed the Abrolhos Bank (AB) leading to a new coastline configuration. Presently, the interaction between the AB and the BC generated a new oceanographic feature in SBM, the Vitoria Eddy, with very limited efficiency in producing a strong upwelling such as the one recorded in the past.