Description: Summary The major goal of the RV METEOR cruise M156 to Cape Verdian waters and the Mauritanian upwelling area off West Africa was to contribute to a better quantitative understanding of the effects of mesoscale eddies on CO2 source/sink mechanisms and the biological carbon pump in eastern boundary upwelling areas as well as their effects to the oligotrophic periphery including the deep-sea floor. The cruise M156 (MOSES Eddy Study I) was conducted within the framework of the BMBF funded REEBUS project (Role of Eddies in the Carbon Pump of Eastern Boundary Upwelling Systems) by a consortium of physical, biological (benthic microbiology, bacterial plankton, protists) and biogeochemical oceanographers. Specific aims were i. the quantification of solute and particle fluxes within and at the periphery of eddies; ii. to determine the turnover of carbon species, air-sea gas exchange of CO2, iii. the determination of the protistan and bacterial plankton community structures in the surface layers of an eddy, and iv. to quantify the magnitude and variability of material fluxes to the seabed and turnover in the sediment underneath the eddy passage. To achieve these aims, the cruise had two major observing strategies: i. an intense benthic/pelagic program along the zonal eddy passage at 18°N. Along this corridor ranging from 24°20’ to 16°30’W, five benthic/pelagic stations (E1 to E5) in different water depths and distances from the Mauritanian coast were performed. The motivation for this survey has been to resolve zonal gradients in pelagic element cycling as well as of organic matter degradation and burial in the seabed, which in turn could potentially be linked with changes in eddy induced primary- and export production. ii. the detailed investigation of an individual eddy to investigate physical, biogeochemical and biological processes on meso- to submeso-scales (100km to 10m). Satellite data analysis was performed before and during the cruise to identify a suitable eddy from a combination of sea-level anomaly, ocean color as Chl-a proxy, and sea-surface temperature supplemented with shipboard current velocity measurements. A total of 171 stations were sampled. The water column program consists of 59 CTD casts, 29 MSS and 20 Marine Snow Catcher deployments. For biogeochemical measurements at the sea surface two deployments of a Lagrangian Surface Drifter and one Waveglider deployment were conducted. At the seafloor, we conducted 10 BIGO deployments. Ten seafloor imaging surveys were performed using the towed camera system OFOS, supplemented with 7 Multibeam and 1 Sidescan surveys. In deviation from the cruise proposal, the planned long-term deployment of a Lander, which was planned to record a time series of oxygen fluxes during the passage of an eddy, was not deployed due to a major delay in its design and manufacturing. The planned AUV (Girona 500) deployments at the shallow E5 station close to the Mauritanian coast station did also not take place. Despite moderate weather conditions, all deployments were successful, hence all the data and sample material aimed for has been achieved. It is to expect that as planned all scientific questions can be addressed. Especially in the synthesis of all REEBUS cruises and the consideration of data from earlier cruises (MSM17/4, M107) into this region a high scientific potential can be expected.

Description: Cruise M160 is part of concerted MOSES/REEBUS Eddy Study featuring three major research expeditions (M156, M160, MSM104). It aims to develop both a qualitative and quantitative understanding of the role of physical-chemical-biological coupling in eddies for the biological pump. The study is part of the MOSES “Ocean Eddies” event chain, which follows three major hypotheses to be addressed by the MOSES/REEBUS field campaigns: (1) Mesoscale and sub-mesoscale eddies play an important role in transferring energy along the energy cascade from the large-scale circulation to dissipation at the molecular level. (2) Mesoscale and sub-mesoscale eddies are important drivers in determining onset, magnitude and characteristics of biological productivity in the ocean and contribute significantly to global primary production and particle export and transfer to the deep ocean. (3) Mesoscale and sub-mesoscale eddies are important for shaping extreme biogeochemical environments (e.g., pH, oxygen) in the oceans, thus acting as a source/sink function for greenhouse gases. In contrast to the other two legs, MOSES Eddy Study II during M160 did not include any benthic work but focused entirely on the pelagic dynamics within eddies. It accomplished a multi-disciplinary, multi-parameter and multi-platform study of two discrete cyclonic eddies in an unprecedented complexity. The pre-cruise search for discrete eddies suitable for detailed study during M160 had already started a few months prior to the cruise. Remote sensing data products (sea surface height, sea surface temperature, ocean color/chlorophyll a) were used in combination with eddy detection algorithms and numerical modelling to identify and track eddies in the entire eddy field off West Africa. In addition, 2 gliders and 1 waveglider had been set out from Mindelo/Cabo Verde for pre-cruise mapping of the potential working area north of the Cabo Verdean archipelago. At the start of M160, a few suitable eddies – mostly of cyclonic type – had been identified, some of which were outside the safe operation range of the motorglider plane. As technical problems delayed the flight operations, the first eddy (center at 14.5°N/25°W) for detailed study was chosen to the southwest of the island of Fogo. It was decided to carry out a first hydrographic survey there followed by the deployment of a suite of instruments (gliders, waveglider, floats, drifter short-term mooring). Such instrumented, we left this first eddy and transited – via a strong anticyclonic feature southwest of the island of Santiago – to the region northeast of the island of Sal, i.e. in the working range of the glider plane. During the transit, a full suite of underway measurements as well as CTD/RO section along 22°W (16°-18.5°N) were carried in search for sub-surface expressions of anticyclonic eddy features. In the northeast, we had identified the second strong cyclonic eddy (center at 18°N/22.5°W) which was chosen for detailed study starting with a complete hydrographic survey (ADCP, CTD/RO, other routine station work). After completion of the mesoscale work program, we identified a strong frontal region at the southwestern rim of the cyclonic eddy, which was chosen for the first sub-mesoscale study with aerial observation component. There, the first dye release experiment was carried out which consisted of the dye release itself followed by an intense multi-platforms study of the vertical and horizontal spreading of the initial dye streak. This work was METEOR-Berichte, Cruise M160, Mindelo – Mindelo, 23.11.2019 4 – 20.12.2019 supported and partly guided by aerial observation of the research motorglider Stemme, which was still somewhat compromised by technical issues and meteorological conditions (high cloud cover, Saharan dust event). Nevertheless, this first dye release experiment was successful and showed rapid movement of the dynamic meandering front. After completion of work on this second eddy and execution of a focused sampling program at the Cape Verde Ocean Observation, RV METEOR returned to the first eddy for continuation of the work started there in the beginning of the cruise. This was accompanied by a relocation of the airbase of Stemme from the international airport of Sal to the domestic airport of Fogo. The further execution of the eddy study at this first eddy, which again included a complete hydrographic survey followed by a mesoscale eddy study with dye release, was therefore possible with aerial observations providing important guidance for work on RV METEOR. Overall, M160 accomplished an extremely intense and complex work program with 212 instrument deployments during station work, 137 h of observation with towed instruments and a wide range of underway measurements throughout the cruise. Up to about 30 individually tracked platforms (Seadrones, glider, wavegliders, drifters, floats) were in the water at the same time providing unprecedented and orchestrated observation capabilities in an eddy. All planned work components were achieved and all working groups acquired the expected numbers of instrument deployments and sampling opportunities.

Description: This document describes the deployment of instrumentation in the Eastern tropical Atlantic area and shows the preliminary data acquired.

Description: Accurate assessment of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere in a changing climate is critical to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe and synthesize data sets and methodology to quantify the five major components of the global carbon budget and their uncertainties. Fossil CO2 emissions (E-FOS) are based on energy statistics and cement production data, while emissions from land-use change (E-LUC), mainly deforestation, are based on land-use and land-use change data and bookkeeping models. Atmospheric CO2 concentration is measured directly, and its growth rate (G(ATM)) is computed from the annual changes in concentration. The ocean CO2 sink (S-OCEAN) is estimated with global ocean biogeochemistry models and observation-based fCO(2) products. The terrestrial CO2 sink (S-LAND) is estimated with dynamic global vegetation models. Additional lines of evidence on land and ocean sinks are provided by atmospheric inversions, atmospheric oxygen measurements, and Earth system models. The resulting carbon budget imbalance (B-IM), the difference between the estimated total emissions and the estimated changes in the atmosphere, ocean, and terrestrial biosphere, is a measure of imperfect data and incomplete understanding of the contemporary carbon cycle. All uncertainties are reported as +/- 1 sigma. For the year 2022, E-FOS increased by 0.9% relative to 2021, with fossil emissions at 9.9 +/- 0.5 GtC yr(-1) (10.2 +/- 0.5 GtC yr(-1) when the cement carbonation sink is not included), and E-LUC was 1.2 +/- 0.7 GtC yr(-1), for a total anthropogenic CO2 emission (including the cement carbonation sink) of 11.1 +/- 0.8 GtC yr(-1) (40.7 +/- 3.2 GtCO(2) yr(-1)). Also, for 2022, G(ATM) was 4.6 +/- 0.2 GtC yr(-1) (2.18 +/- 0.1 ppm yr(-1); ppm denotes parts per million), S-OCEAN was 2.8 +/- 0.4 GtC yr(-1), and S-LAND was 3.8 +/- 0.8 GtC yr(-1), with a B-IM of 0.1 GtC yr(-1) (i.e. total estimated sources marginally too low or sinks marginally too high). The global atmospheric CO2 concentration averaged over 2022 reached 417.1 +/- 0.1 ppm. Preliminary data for 2023 suggest an increase in E-FOS relative to 2022 of +/- 1:1% (0.0% to 2.1 %) globally and atmospheric CO2 concentration reaching 419.3 ppm, 51% above the pre-industrial level (around 278 ppm in 1750). Overall, the mean of and trend in the components of the global carbon budget are consistently estimated over the period 1959-2022, with a near-zero overall budget imbalance, although discrepancies of up to around 1 Gt Cyr(-1) persist for the representation of annual to semi-decadal variability in CO2 fluxes. Comparison of estimates from multiple approaches and observations shows the following: (1) a persistent large uncertainty in the estimate of land-use changes emissions, (2) a low agreement between the different methods on the magnitude of the land CO2 flux in the northern extra-tropics, and (3) a discrepancy between the different methods on the strength of the ocean sink over the last decade. This living-data update documents changes in methods and data sets applied to this most recent global carbon budget as well as evolving community understanding of the global carbon cycle.

Description: Discrete samples for dissolved oxygen (DO), nutrients, dissolved inorganic carbon (DIC) and total alkalinity (TA) were taken from CTD rosette casts during the RV METEOR cruise M160 in the Cape Verde region. This cruise was part of the REEBUS project focusing on researching oceanic eddies generated in the Mauritanian upwelling system. Therefore, the majority of the samples were either taken within or in close proximity to oceanic eddies. Dissolved oxygen, determined via Winkler titration, and nutrient samples, analysed with a SEAL Analytical QuAAtro AutoAnalyzer, were both measured on the vessel within 24 hours of sampling. Samples for DIC and TA analysis were taken in Duran glass bottles, poisoned with Mercury(II) chloride and stored to be analysed at GEOMAR using a SOMMA and VINDTA 3S respectively.

Description: Underway data for dissolved oxygen, total dissolved gas pressure, fluorescence and turbidity have been collected along the track of the RV METEOR cruise M160 around the Cape Verde archipelago. Water was pumped from the moon pool at 5 m depth into an insulated box, where the sensors were located. Discrete samples for dissolved oxygen were taken from the water stream and analysed on board by Winkler titration to correct the sensor data. Salinity data used for corrections and conversions was taken from the shipside TSG measurements at 5m depth.

Description: In the framework of the EuroSea project (Task 7.3), a demonstration mission in the Tropical Atlantic has been conducted to enhance and optimize the network design of the Tropical Atlantic Observing System (TAOS) following an integrative multi-platform approach. One Gen6 Saildrone Explorer USV equipped with a CTD, wind, and carbon measurements systems sailed to the Cape Verde region where it acquired data between September 2021 and February 2023. Objectives for this mission include developing an integrated multi-platform approach to improving carbon monitoring, data quality, and regional upscaling from moored instrumentation, biogeochemical Argo floats, autonomous surface observation, and remote sensing products.

Description: In the framework of the EuroSea project (Task 7.3), a demonstration mission in the Tropical Atlantic has been conducted to enhance and optimize the network design of the Tropical Atlantic Observing System (TAOS) following an integrative multi-platform approach. One Gen6 Saildrone Explorer USV equipped with a CTD, wind, and carbon measurements systems sailed to the Cape Verde region where it acquired data between September 2021 and February 2023. Objectives for this mission include developing an integrated multi-platform approach to improving carbon monitoring, data quality, and regional upscaling from moored instrumentation, biogeochemical Argo floats, autonomous surface observation, and remote sensing products.

Description: In the framework of the EuroSea project (Task 7.3), a demonstration mission in the Tropical Atlantic has been conducted to enhance and optimize the network design of the Tropical Atlantic Observing System (TAOS) following an integrative multi-platform approach. One Gen6 Saildrone Explorer USV equipped with a CTD, wind, and carbon measurements systems sailed to the Cape Verde region where it acquired data between September 2021 and February 2023. Objectives for this mission include developing an integrated multi-platform approach to improving carbon monitoring, data quality, and regional upscaling from moored instrumentation, biogeochemical Argo floats, autonomous surface observation, and remote sensing products. The ASVCO2 system (pCO2 sensor type) on the SailDrone is equipped with on-board reference gas containers to calibrate itself before and after each measurement, and readings of zero gas and reference gas values (that span the ocean pCO2 values of the location where the system is deployed) are made immediately before the calibration.