Description: Flow-through pCO2, Temp/Sal, and O2 measurements across the Atlantic (Meteor M133 cruise 2016/17) from Cape Town, SA to Stanley, The Falkland Islands. Surface water flow-through system set up on R.V. Meteor M133 (15.12.2016 - 13.01.2017), across the Atlantic. All sensors ran on the same water in a complete flow-through sensor set-up. Depth of pumps: 5.7m from the moon pool Flow rate: ~ 5-6 L/min All data was processed following Canning et al., 2020 (In Review). Sensor data in separate files. Sensors: pCO2: CONTROS HydroC CO2 FT - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany; now -4H-JENA engineering GmbH, Jena, Germany O2: CONTROS HydroFlash O2 - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany SBE 45 Micro Thermosalinograph - Sea-Bird Electronics, Bellevue, USA D-SHIP data from the ships SBE 38 and 21 for sea surface temperature and salinity. Latitude and longitude also from the D-SHIP. All sensors combined together in the same flow-through set-up.

Description: Flow-through pCO2, Temp/Sal, and O2 measurements across the Atlantic (Meteor M133 cruise 2016/17) from Cape Town, SA to Stanley, The Falkland Islands. Surface water flow-through system set up on R.V. Meteor M133 (15.12.2016 - 13.01.2017), across the Atlantic. All sensors ran on the same water in a complete flow-through sensor set-up. Depth of pumps: 5.7m from the moon pool Flow rate: ~ 5-6 L/min All data was processed following Canning et al., 2020 (In Review). Sensor data in separate files. Sensors: pCO2: CONTROS HydroC CO2 FT - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany; now -4H-JENA engineering GmbH, Jena, Germany O2: CONTROS HydroFlash O2 - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany SBE 45 Micro Thermosalinograph - Sea-Bird Electronics, Bellevue, USA D-SHIP data from the ships SBE 38 and 21 for sea surface temperature and salinity. Latitude and longitude also from the D-SHIP. All sensors combined together in the same flow-through set-up.

Description: Flow-through pCO2, Temp/Sal, and O2 measurements across the Atlantic (Meteor M133 cruise 2016/17) from Cape Town, SA to Stanley, The Falkland Islands. Surface water flow-through system set up on R.V. Meteor M133 (15.12.2016 - 13.01.2017), across the Atlantic. All sensors ran on the same water in a complete flow-through sensor set-up. Depth of pumps: 5.7m from the moon pool Flow rate: ~ 5-6 L/min All data was processed following Canning et al., 2020 (In Review). Sensor data in separate files. Sensors: pCO2: CONTROS HydroC CO2 FT - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany; now -4H-JENA engineering GmbH, Jena, Germany O2: CONTROS HydroFlash O2 - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany SBE 45 Micro Thermosalinograph - Sea-Bird Electronics, Bellevue, USA D-SHIP data from the ships SBE 38 and 21 for sea surface temperature and salinity. Latitude and longitude also from the D-SHIP. All sensors combined together in the same flow-through set-up.

Description: Flow-through pCO2, pCH4 Temp/Sal, and O2 measurements in the western Baltic Sea during SCOR cruise (separate to the intercalibration exercise). Surface water flow-through sensor system set up on R.V. Elisabeth Mann Borgese (15.10.2016 - 22.10.2016). All sensors ran on the same water in a complete flow-through sensor set-up at a resolution of 1 minute. Depth of pumps: 3m Flow rate: ~ 5-6 L/min All data was processed following Canning et al., 2020 (In Review). Sensor data in separate files. Sensors: pCO2: CONTROS HydroC CO2 FT - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany; now -4H-JENA engineering GmbH, Jena, Germany O2: CONTROS HydroFlash O2 - formerly Kongsberg Maritime Contros GmbH, Kiel, Germany SBE 45 Micro Thermosalinograph - Sea-Bird Electronics, Bellevue, USA Temperature, salinity, latitude and longitude included are also from the D-SHIP. Only half the cruise dataset for pCH4 due to internal issue with the sensor (see Canning et al., 2020).

Description: The need to cover established and emerging Essential Ocean Variables (EOVs) as defined by the Global Ocean Observing System (GOOS) calls for the development and refinement of the available sensors and samplers, specifically for biogeochemical and biology/ecosystem observations. For several of these EOVs as well as for microplastics as a relatively novel variable of particular societal concern, technological progress has been made as part of AtlantOS. This involves the samplers and sensors and the platforms to use them from as such as well as the required methodologies for obtaining relevant and well-validated results and disseminate data according to the FAIR principles. For biological observations, a main focus was on automated sampling of particles and water samples. While active, pump-based samplers for particles in the water column have been available for many years, it turned out that they were not yet fully mature for operational sampling of zooplankton, microorganisms (e.g., bacteria, archaea, phytoplankton and other eukaryotic unicellular organisms), and microplastics. AtlantOS partners joined forces with manufacturers to overcome limitations with respect to quantitative filtering without leakage, avoidance of plastic contamination and the option for preservation with appropriate agents. Technical solutions were identified and partly tested but could not in all cases be fully implemented in the time frame of the project. Technologies for automated water sampling proved to be more mature and samplers could already be successfully included in observation programs. For both water and particle samples only very few manufacturers offer off-the-shelf solutions which slows down innovation and adaption to user’s needs and may impede successful implementation of appropriate instruments on a larger scale. Particle traps are well-established and operational passive samplers of sinking particles that are widely used for phytoplankton and particulate matter observations based on microscopic sorting and chemical analyses. Using legacy samples collected in the Arctic it could be demonstrated that the same samples can also be used for omics-based observations allowing to address the emerging EOV ‘Microbe biomass and diversity’ and also contributing to the ‘Phytoplankton biomass and diversity’ EOV. Applied to legacy samples also from other sites, this holds the potential to assess past microbial communities of the Atlantic that could serve as a baseline for comparisons to recent communities that are subject to global change. Significant progress was achieved in building capacities for the implementation of omics-based observations of marine organisms into recent and future observation programs. The feasibility of samplers and different preservation agents was tested and a comparison of different methods for omics-based investigations of microbial communities was conducted. The Global Omics Observatory Network (GLOMICON) was established to better connect the institutes and initiatives that are active in the field. As part of GLOMICON, solutions were implemented that allow for a registration of omics observatories and for the sharing of protocols and bioinformatics code. Irrespective of these achievements, major steps still need to be taken to consolidate and standardize approaches in this rapidly evolving field and to establish operational and well-integrated omics-observations as part of an Atlantic Ocean Observation System. For biogeochemical observations, the focus was placed on sensors for oxygen and marine CO2 system parameters (pCO2, total alkalinity) and their readiness for integration into classical as well as emerging biogeochemical observation platforms. For oxygen, the situation is very favourable as the oxygen optode technology and the best practices routines developed around it can be considered fully operational. There are no obstacles for the D3.17 „OceanSITES Innovation Report“ 5 integration of oxygen optodes into the full range of autonomous ocean observation platforms (mooring, drifter, glider, wave gliders, floats, voluntary observing ship etc.). For marine CO2 system parameters, work carried out in AtlantOS focussed the CO2 partial pressure (pCO2) and total alkalinity (TA). With respect to pCO2 it can be stated, that the membraneequilibration sensors with NDIR detection have clearly matured to a level that they can be used routinely on a range of platforms (mooring, wave glider, voluntary observing ship) with an accuracy of ~1% under well-constrained operation conditions and with rigorous data processing routines. Major limitations still exist, however, for this sensor technology on moving platforms (long sensor response time) and platforms with stringent payload and energy limitations (float, glider etc.). In contrast, the pCO2 (as well as pH) optode technology, in which significant hopes lie, has not been forthcoming and existing products still do not meet the quality requirements for open ocean applications. For TA, our intensive testing both in the laboratory and in the field has led to significant improvement of the commercially available system, which now can be considered operational. It allows high-quality autonomous bench-top measurements (e.g., on voluntary observing ships). Ideas for a submersible version of the system are in early stages and would need significant design and testing efforts. With respect to the possibilities of oxygen and carbon measurements from novel autonomous observation platforms, our work in AltantOS has shown very promising applications on profiling Argo floats, submersible winch systems with upper ocean profilers as well as wave gliders. On all these platforms, we were able to successfully implement oxygen and carbon measurements for high-quality observations.

Description: Innovation and improvement report on the extension of capabilities to measure emerging EOVs including metagenomics across different observational platforms with links to MicroB3 best practice.

Description: Ocean warming severely impacts oxygen distribution, because it reduces oxygen solubility and increases stratification in the upper ocean. Quantifying changes of oxygen levels will improve the understanding of chemical, biological and physical processes, especially in Oxygen Minimum Zones characterized by intensification and spatial expansion. Despite existing optical sensors (optodes) that accurately measure ocean oxygen levels, users wish for an improved spatial and temporal measurement resolution from profiling platforms. We demonstrate the utility of a novel, commercially-available optode that shows a temperature-dependent response time (t63%) of about 4 seconds, which is significantly faster compared to other optical oxygen sensors. This optode can be used on a wide range of observation platforms such as ships, time-series stations, unmanned surface vehicles and autonomous underwater platforms such as floats and gliders. We aim to characterize this optode regarding oxygen, temperature, salinity and pressure dependence, long-term stability and drift, response time and air-calibration compatibility. Results build on data from laboratory experiments and field deployments in the Tropical and Southern Atlantic. Underway, mooring, float and CTD-cast applications promise high quality observations including fast oxygen level changes on small scales. We will conclude with a status update on our general optode technology developments.

Description: Carbon dioxide (CO2) and methane (CH4) are major greenhouse gases (GHG) and have been under constant monitoring for decades. Both gases have significantly increased in recent years due to anthropogenic activities. This has huge detrimental repercussions within natural systems including the warming of the planet. Although these GHG are extremely significant, there are also vast areas of study with little to no data in regards to emissions and budgets. These gaps are mainly within the aquatic regions (or the Land Ocean Aquatic Continuum (LOAC)). As a consequence, there can be large discrepancies between budget numbers and in turn, scaling and future predictions. In order to combine oceanographic and limnological methods this thesis presents a novel sensor package and show its application in multiple campaigns across the entire LOAC. The sensor set-up contained the oceanographic sensors HydroC CO2 FT (pCO2), HydroC CH4 FT (CH4), HydroFlash O2 (O2) and a thermosalinograph for temperature and conductivity measuring continuously, all simultaneously. We extensively mapped ocean to inland regions. The results first describe the processes to enable the set-up to be used across the LOAC boundary over 3 seasons. Extensive corrections were needed for the data to be fully appreciated for all salinities specifically in fresh inland waters. The data was then split between CO2 and CH4, where, in inland waters, further analyses were performed. The area of interest was the Danube Delta, which was found to be continuously supersaturated in regards to CH4 and fluctuating between a source and sink for CO2. Extraction of TA was possible, using the sensors continuous data by applying a simple model. In this extraction and the continuous data, large spatial-variability was observed and further analysed allowed for diel cycle extractions, which are usually disregarded in budgets and measurements. In channels, CH4 concentrations and fluxes were found to potentially be underestimated by up to +25% and +20% respectively when not including a full diel cycle. In lakes however, we found the opposite, with an overestimation in concentration and fluxes (+3.3% and +4.2%) when not considering the diel cycle, although this greatly depends on time of the sampling.

Description: Large amounts of methane (CH4) could be released as a result of the gradual or abrupt thawing of Arctic permafrost due to global warming. Once available, this potent greenhouse gas is emitted into the atmosphere or transported laterally into aquatic ecosystems via hydrologic connectivity at the surface or via groundwaters. While high northern latitudes contribute up to 5 % of total global CH4 emissions, the specific contribution of Arctic rivers and streams is largely unknown. We analyzed high-resolution continuous CH4 concentrations measured between 15 and 17 June 2019 (late freshet) in a ∼120 km transect of the Kolyma River in northeast Siberia. The average partial pressure of CH4 (pCH4) in tributaries (66.8–206.8 µatm) was 2–7 times higher than in the main river channel (28.3 µatm). In the main channel, CH4 was up to 1600 % supersaturated with respect to atmospheric equilibrium. Key sites along the riverbank and at tributary confluences accounted for 10 % of the navigated transect and had the highest pCH4 (41 ± 7 µatm) and CH4 emissions (0.03 ± 0.004 ) compared to other sites in the main channel, contributing between 14 % to 17 % of the total CH4 flux in the transect. These key sites were characterized by warm waters (T〉14.5 ∘C) and low specific conductivities (κ〈88 µS cm−1). The distribution of CH4 in the river could be linked statistically to T and κ of the water and to their proximity to the shore z, and these parameters served as predictors of CH4 concentrations in unsampled river areas. The abundance of CH4-consuming bacteria and CH4-producing archaea in the river was similar to those previously detected in nearby soils and was also strongly correlated to T and κ. These findings imply that the source of riverine CH4 is closely related with sites near land. The average total CH4 flux density in the river section was 0.02 ± 0.006 , equivalent to an annual CH4 flux of 1.24×107 g CH4 yr−1 emitted during a 146 d open water season. Our study highlights the importance of high-resolution continuous CH4 measurements in Arctic rivers for identifying spatial and temporal variations, as well as providing a glimpse of the magnitude of riverine CH4 emissions in the Arctic and their potential relevance to regional CH4 budgets.