ALBERT

Description: Dissolved Organic Matter, Cell Abundance and Extracellular Enzyme Rates and Bacterial Production from several cruises and experiments from 2008-2018

Description: A Hydrobios Multinet Midi with an aperture of 0.25 m2 and 5 nets (mesh size 200 μm) was deployed for vertically stratified hauls on several cruises, mostly in paired day-night hauls to quantify diel vertical migration. Standard depths used for these deployments were 1000-600-300-200-100-0 m. On M93, a Multinet Maxi (9 nets, 333 μm mesh) was used instead. Samples were fixated in 4% formaldehyde in seawater solution, scanned at GEOMAR or at OSCM, and analyzed using automated imaging software (Gorsky et al., 2010) allowing taxonomical classification as well as the estimation of taxon-specific biomass (Lehette and Hernandez-Leon, 2006) and metabolic rates.

Description: To expand the ecological knowledge on fragile organisms (such as giant rhizaria, medusae, ctenophores, and siphonophores) in situ imaging techniques were employed in addition to net sampling. An Underwater Vision Profiler 5 (UVP5; Picheral et al., 2010) was routinely mounted on the CTD/rosette during most SFB 754 cruises since 2012. During the cruises in 2012 and 2013 a UVP5 was used that was kindly provided by the Laboratoire d'Océangraphie de Villefranche-sur-Mer. The instrument consists of one down facing HD camera in a steel pressure case and two red LED lights which illuminate a 0.88 to 0.93 l volume (depending on the actual set-up). During the downcast, the UVP5 takes 3-20 pictures of the illuminated field per second. For each picture, the particles are counted and sized immediately and the data is stored in the instrument for later analysis.

Description: Zooplankton metabolic rates (oxygen respiration and ammonium excretion) at different temperatures, oxygen, and carbon dioxide partial pressures (Kiko et al., 2015; 2016) were measured during three cruises. Zooplankton was collected by different nets and the entire catch immediately transferred to 10 l beakers containing pre-cooled seawater. Diel vertical migrators were sampled at the surface at night. Individuals for respiration rate measurements were isolated immediately and maintained in filtered seawater for 1 to 13 hours at the chosen experimental temperature (13, 18 or 23°C). Only animals appearing unharmed and fit were used for experiments. Water for the respiration and excretion rate trials was UV-treated, filtered over a 0.2 µm sterile filter, and supplemented with antibiotics (25 mg l-1 ampicillin and 25 mg l-1 streptomycin). Subsequently, the water was bubbled with different Gas mixtures (N2, O2, CO2, see Kiko et al., 2016 for details) adjusted to the chosen pO2 and pCO2 levels.

Description: One of the objectives of the SFB 754 was the reconstruction of the factors controlling the intensity and the spatial extent of the OMZ in the Eastern Tropical Pacific, specifically off Peru, since the Last Glacial Maximum (21000 years ago). For the purpose of these paleoceanographic studies, long gravity cores were recovered during four scientific expeditions (M77/1, M77/2, M92, and M135; see Figure 4). During the cruises M77/1 and M77/2 in 2008, 51 sediment cores were retrieved below and in the centre of the OMZ, from ~17° S to the equator (Pfannkuche et al., 2011; see Figure 4). Most of the records collected in the core of the OMZ (i.e. ~200 to ~500 m depth), from ~8 to 15° S, show sedimentary discontinuities during the Holocene (last 11700 years), which preclude high resolution paleoceanographic reconstructions in this area (Erdem et al., 2016; Salvatteci et al., 2014, 2016). Based on the information collected during M77/1 and M77/2 and also on the scientific literature, cruise M135 aimed specifically at finding the most complete Holocene sequence in the Eastern Tropical South Pacific. For this purpose, a detailed paleoceanographic survey took place at ~17° S, an area that is less affected by processes that can produce sediment discontinuities. Six sediment cores were retrieved, two of which contained the most complete sediment sequences for the last 10 000 years (Salvatteci et al., 2019).

Description: One of the objectives of the SFB 754 was the reconstruction of the factors controlling the intensity and the spatial extent of the OMZ in the Eastern Tropical Pacific, specifically off Peru, since the Last Glacial Maximum (21000 years ago). For the purpose of these paleoceanographic studies, long gravity cores were recovered during four scientific expeditions (M77/1, M77/2, M92, and M135; see Figure 4). During the cruises M77/1 and M77/2 in 2008, 51 sediment cores were retrieved below and in the centre of the OMZ, from ~17° S to the equator (Pfannkuche et al., 2011; see Figure 4). Most of the records collected in the core of the OMZ (i.e. ~200 to ~500 m depth), from ~8 to 15° S, show sedimentary discontinuities during the Holocene (last 11700 years), which preclude high resolution paleoceanographic reconstructions in this area (Erdem et al., 2016; Salvatteci et al., 2014, 2016). Based on the information collected during M77/1 and M77/2 and also on the scientific literature, cruise M135 aimed specifically at finding the most complete Holocene sequence in the Eastern Tropical South Pacific. For this purpose, a detailed paleoceanographic survey took place at ~17° S, an area that is less affected by processes that can produce sediment discontinuities. Six sediment cores were retrieved, two of which contained the most complete sediment sequences for the last 10 000 years (Salvatteci et al., 2019).

Description: One of the objectives of the SFB 754 was the reconstruction of the factors controlling the intensity and the spatial extent of the OMZ in the Eastern Tropical Pacific, specifically off Peru, since the Last Glacial Maximum (21000 years ago). For the purpose of these paleoceanographic studies, long gravity cores were recovered during four scientific expeditions (M77/1, M77/2, M92, and M135; see Figure 4). During the cruises M77/1 and M77/2 in 2008, 51 sediment cores were retrieved below and in the centre of the OMZ, from ~17° S to the equator (Pfannkuche et al., 2011; see Figure 4). Most of the records collected in the core of the OMZ (i.e. ~200 to ~500 m depth), from ~8 to 15° S, show sedimentary discontinuities during the Holocene (last 11700 years), which preclude high resolution paleoceanographic reconstructions in this area (Erdem et al., 2016; Salvatteci et al., 2014, 2016). Based on the information collected during M77/1 and M77/2 and also on the scientific literature, cruise M135 aimed specifically at finding the most complete Holocene sequence in the Eastern Tropical South Pacific. For this purpose, a detailed paleoceanographic survey took place at ~17° S, an area that is less affected by processes that can produce sediment discontinuities. Six sediment cores were retrieved, two of which contained the most complete sediment sequences for the last 10 000 years (Salvatteci et al., 2019). In addition, core tops of near sediment surface cores from multi-corers (MUCs) have been used to establish local calibrations for several paleoproxies, such as redox-sensitive elements in foraminifera (i.e. Mn/Ca, I/Ca and Fe/Ca), foraminiferal assemblages, and stable Mo and N isotopes

Description: Trace metal clean sampling equipment was deployed on a sub-set of cruises to facilitate the observation of contamination prone chemical parameters. All trace metal sample collection, handling, and analysis was conducted in accordance with GEOTRACES protocols which have been updated through the SFB754 program (Cutter et al., 2014). For cruises with extensive trace metal work, the deployment of an over-pressured clean container on deck facilitated sampling and collection of trace metal and other contamination-prone samples at sea. For cruises from 2008 to 2013, PTFE-coated 8 l GO-FLO bottles (General Oceanics) were mounted on a Kevlar wire with sample handling and preservation as per Chever et al. (2015). From 2014 onwards, 24 Ocean Test Equipment (OTE) samplers were deployed mounted on a powder coated sampling CTD (Sea-Bird SBE25) rosette using a Kevlar conducting cable with sample handling and preservation as per Rapp et al. (2019).

Description: Seawater samples for stable isotopes measurements of dissolved silicate (δ30Si), nitrate (δ15NO3-) and nitrite (δ15NO2-) were taken from the CTD/rosette on a number of SFB 754 cruises. Seawater samples for Rare Earth Element (REE) concentrations and neodymium (Nd) isotopes were taken during M77/3, M77/4 (Grasse et al., 2012) and during M90 in the Panama Basin (Grasse et al., 2017).

Description: SADCP data were acquired on 33 of the research cruises On FS Meteor, FS Maria S. Merian and FS Sonne II two Teledyne RDI Ocean Surveyor systems with 38 and 75 kHz transmission frequency were used, while on NO l'Atalante a single 75 kHz system was used. All data was processed with a software package developed at GEOMAR following the GO-SHIP standards (Firing and Hummon, 2010). The data was subsequently averaged over one minute intervals, converted to a NetCDF based format and published. For a small number of cruises, the signal strength information of the SADCP data has also been used to estimate the backscatter in the ocean. These data sets were processed following Mullinson (2017) and published separately from the regular SADCP data (see also Table C7).