ALBERT

Description: Autonomous gliders were deployed during several cruises but also as stand-alone missions independent from large research vessels (see Table C5). Two different generations of Teledyne Webb Research Slocum gliders were used, G1 and G2. All gliders were equipped with Seabird CTD systems, G1 gliders with an unpumped and G2 gliders with a pumped version, respectively. An Aanderaa optode was present on all gliders to observe dissolved oxygen concentrations. Optical fluorescence and backscatter sensors manufactured by Wetlabs were also present on all gliders albeit in different configurations. They allowed the determination of CHL-a (excitation and emission wavelengths of 470 and 695 nm, respectively) and CDOM (excitation and emission wavelengths of 370 and 460 nm, respectively) concentrations and the turbidity (scattering wavelength of 470 nm) of the waters. All glider data was processed using a GEOMAR-developed software (Thomsen et al., 2016) resulting in gridded fields for all observed variables. During a small number of glider deployments, a Seabird/Satlantic SUNA Nitrate sensor was attached to a glider. SUNA data was again processed following the procedures outlined in Sakamoto et al. (2009) and Sakamoto et al. (2017) and calibrated against Nitrate measurements from nearby CTDO casts with discrete Nitrate measurements. Microstructure sensors were also attached to gliders on several deployments (see the following section).

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: 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: lmost all long-term moored observations of the SFB 754 were conducted in the tropical Atlantic between the equator and 18° N, except for one mooring that was deployed in the tropical South Pacific (see Table C4). Moorings were typically equipped with instruments recording pressure, temperature, conductivity, dissolved oxygen and current velocity. The moorings at 17.6° N, 24.2° W which have been deployed in the same location for several periods were additionally equipped with biogeochemical sensors recording variables such as partial pressure of CO2 (pCO2), fluorescence, and particle fluxes. Instruments with pressure, temperature, conductivity and oxygen sensors were calibrated in situ immediately prior to and after a mooring deployment period by attaching them to the CTD frame during CTDO casts. Correction terms were then developed from the difference between the sensor readings and the calibrated CTDO data during several minute long calibration stops. These correction terms were then applied to the full deployment periods. This ensured best data quality with recognition of potential sensor drifts and also allowed for the estimation of calibration and measurement errors (Hahn et al. 2014, Bittig et al. 2018, Berx et al. 2019). Moored Acoustic Doppler Current Profiler bin depths were corrected using the sound speed at instrument depth following the approach by Shcherbina et al. (2005). Velocities were not corrected, but respective measurement errors were assumed as described in Hahn et al. (2014). For all instruments within a mooring that did not record pressure, full deployment pressure time series were estimated by linearly interpolating between the instruments having a pressure sensor.

Description: Nutrient, transient tracer and N2O water column measurements

Description: Continuous measurements of the climate-relevant trace gases carbon dioxide (CO2), nitrous oxide (N2O), and carbon monoxide (CO) in the surface ocean and overlying atmosphere were conducted during 9 SFB 754 cruises (see Table C14) spanning the North, South and equatorial Atlantic, as well as the South and equatorial Pacific. To this end, laser spectroscopy-based gas analyzers coupled to air-water equilibration chambers were used. For details of the analytical systems the reader is referred to the descriptions provided by Arévalo-Martínez et al. (2013) and Arévalo-Martínez et al. (2019). All trace gas measurements were quality-controlled to achieve the international standards for marine CO2 (Bender et al., 2002), N2O (Bange et al., 2019), and atmospheric CO (Zellweger et al., 2019; to date there is no accepted standard for seawater measurements). The final quality-controlled data is available through the Surface Ocean CO2 Atlas (SOCAT, https://www.socat.info/) and the Marine CH4-N2O database (MEMENTO, https://memento.geomar.de/) as well as on Pangaea

Description: Particulate organic matter (POM) distribution in the water column as on several cruises determined after filtration onto pre-combusted, acid-washed GF/F filters (Franz et al., 2012a). Particulate organic phosphorus (POP) collected on GF/F filters was determined colorimetrically. Samples for phytoplankton pigment concentrations were collected by filtration of seawater from the CTD/rosette through GF/F filters, and stored at -80°C immediately after filtration. Transparent exopolymer particles (TEP) and Coomassie stainable particles were filtered under low pressure (〈 150 mbar) onto 25 mm Nuclepore membrane filters (0.4 μm pore size, Whatman Ltd.) and stained with Alcian Blue and Coomassie Brilliant Blue, respectively. Export flux of was characterized using surface-tethered sediment traps (Engel et al., 2017), with Particle Interceptor-Traps (PIT) following Knauer et al. (1979).

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