Abstract.Water column data of carbon and carbon-relevant parameters have been collected and merged into a new database called CARINA (CARbon IN the Atlantic). In order to provide a consistent data set, all data have been examined for systematic biases and adjusted if necessary (secondary quality control (QC)). The CARINA data set is divided into three regions: the Arctic/Nordic Seas, the Atlantic region and the Southern Ocean. Here we present the CFC data for the Atlantic region, including the chlorofluorocarbons CFC-11, CFC-12 and CFC-113 as well as carbon tetrachloride (CCl 4 ). The methods applied for the secondary quality control, a crossover analyses, the investigation of CFC ratios in the ocean and the CFC surface saturation are presented. Based on the results, the CFC data of some cruises are adjusted by a certain factor or given a "poor" quality flag.

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The breaking of internal waves results in diapycnal mixing which plays an important role in different climate relevant processes such as the transport of heat, freshwater, nutrients, pollutants, and dissolved gases. Thus, it is necessary to study the physics that drives diapycnal mixing to adequately represent the ocean's role in the climate system and to construct realistic climate models. Approximately 2 TW are needed to maintain the abyssal stratification of which internal tides contribute the main share, about 0.5-1.5 TW

Low‐mode internal waves propagate over large distances and provide energy for turbulent mixing when they break far from their generation sites. A realistic representation of the oceanic energy cycle in ocean and climate models requires a consistent implementation of their generation, propagation, and dissipation. Here we combine the long‐term mean energy flux from satellite altimetry with results from a 1/10° global ocean general circulation model that resolves the low modes of internal waves and in situ observations of stratification and horizontal currents to study energy flux and dissipation along a 1000 km internal tide beam in the eastern North Atlantic. Internal wave fluxes were estimated from twelve 36‐ to 48‐hr stations in along‐ and across‐beam direction to resolve both the inertial period and tidal cycle. The observed internal tide energy fluxes range from 5.9 kW m−1 near the generation sites to 0.5 kW m−1 at distant stations. Estimates of energy dissipation come from both finestructure and upper ocean microstructure profiles and range, vertically integrated, from 0.5 to 3.3 mW m−2 along the beam. Overall, the in situ observations confirm the internal tide pattern derived from satellite altimetry, but the in situ energy fluxes are more variable and decrease less monotonically along the beam. Internal tides in the model propagate over shorter distances compared to results from altimetry and in situ measurements, but more spatial details close the main generation sites are resolved.

The oceanic crust is initially cooled and deep-sea chemosynthetic ecosystems are largely fed by hydrothermal circulation and venting on the seafloor. Much of this venting takes place at midocean ridges and in order to make realistic models of the crust´s thermal budget and to understand chemosynthetic biogeography it is important to have a detailed inventory of vent sites. Until recently, a major gap in this inventory was the Mid-Atlantic Ridge south of 13°S, a key region for vent fauna biogeography as it is the corridor linking the Atlantic to the Indian and Pacific Oceans. In spring 2013 we systematically surveyed the axial region between 13°S and 33°S for hydrothermal signals in the water column, using turbidity, oxidation-reduction-potential (ORP) and noble gases as indicators. Standard conductivity-temperature-depth (CTD) rosette water-sampler deployments were complimented by a novel autonomous underwater vehicle (AUV) deployment strategy, in which the AUV made single-pass, segment-scale (up to 100 km long) dives close to the seafloor to detect small vents. The ca. 2100 km-long survey covered 16 ridge segments and we identified previously unknown hydrothermal plumes above ten segments that point to 14 new hydrothermal vent fields. The majority of plumes are located at high-relief segment centers, where magmatism is robust. A wide gap in the distribution of vents in the 19°S-23°S region coincides with the Rio de Janeiro Transform, the maximum southward progression of North Atlantic Deep Waters and the maximum northwards extent of 3 He-enriched waters with Pacific origins. Crossflowing currents in the transform and the large gap between adjacent vents may prevent a meridional connection between the vent fauna communities in the North Atlantic and along the Antarctic Ridges. This makes the region a prime target for future biogeographical studies.

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Five years of continuous mooring data combined with conductivity-temperature-depth (CTD)/lowered acoustic Doppler current profiler (LADCP) measurements from five cruises are used to investigate the influence of the deep western boundary current (DWBC) on the internal wave field and associated vertical mixing at the continental slope at 168N in the western Atlantic. The mooring data include 2-hourly rotor current-meter measurements and temperature/conductivity time series with a high temporal resolution of 5-20 min. Thus, the data resolve time scales ranging from the low-frequency variability of the large-scale DWBC that generates internal waves due to interactions with the topography to frequencies greater than that of internal waves that are associated with vertical mixing. Estimates of the vertical mixing induced by the breaking of the observed internal waves show elevated diapycnal diffusivities of up to 10 23 6 0.4 3 10 23 m 2 s 21 in the bottommost 1500 m during times of a strong DWBC (maximum velocities at the mooring site up to 50 cm s 21 ) whereas vertical mixing rates are about an order of magnitude lower (1.6 3 10 24 6 0.6 3 10 24 m 2 s 21 ) during weak flow. During periods of a strong DWBC, spectra of horizontal velocity and internal wave available potential energy change substantially at depths below 1200 m and show a strong increase in variance particularly in the near-inertial frequency band. Low-frequency, near-inertial waves generated by topography/DWBC interaction on the slope to the west of the moorings can potentially cause this observed wave intensification; ray paths estimated for these waves agree well with the observed spectral changes at different depths. Variability in the high-frequency range, considered as a proxy for turbulent mixing, is significantly correlated with the DWBC strength above the continental slope.

Internal gravity waves are disturbances that occur in the stratified ocean and can travel hundreds to thousands of kilometers away from their generation sites (e.g., Alford, 2003b). Internal wave breaking leads to turbulent diapycnal mixing, which plays an important role in different climate relevant processes, such as the transport of heat, freshwater, nutrients, pollutants, and dissolved gases (e.g., MacKinnon et al., 2017). Diapycnal mixing is thought to provide considerable energy to maintain the abyssal stratification and is a major driver of the global meridional overturning circulation (MOC) (Munk & Wunsch, 1998;Wunsch & Ferrari, 2004). It has been demonstrated that the global MOC is sensitive to the strength and spatial distribu-