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Dimethylsulfide (DMS) is a climatically active trace gas promoting cloud formation. The biochemical precursor of DMS, dimethylsulfoniopropionate (DMSP), is a phytoplankton metabolite and a source of reduced sulfur for many microbial species. Because of the complex interactions between their many producers and consumers, the dynamics of DMSP and DMS in the ocean are still poorly constrained. In this study we measure particulate DMSP, dissolved DMSP (), and DMS concentrations in seven mesocosms where two consecutive phytoplankton blooms (first, pico- and nano-algae; second, Emiliania huxleyi) were induced by nutrient addition, and we build a mechanistic numerical model to identify the sources and sinks that best account for the observations. The mesocosms were designed as replicates but differ from each other by their E. huxleyi virus abundance due to stochastic differences in initial conditions. The model shows that heterotrophic bacteria cannot be the only consumers of . A fraction of dissolved must be consumed by phytoplankton to avoid excessive accumulation during the first bloom. The induced blooms increase DMS concentration by 220% on average, until an increase in the abundance of DMS-consuming bacteria brings DMS concentration back to its pre-bloom value, after 3 weeks of experiment. Therefore phytoplankton blooms can increase DMS emission to the atmosphere, but only during a transient regime of a few weeks. The model also shows that the DMS yield, production and emission are increased when the coccolithophore bloom is terminated by a viral infection, but decreased if the infection occurs several days before the bloom can reach its maximum

[EN] Since Lovelock and Margulis introduced the Gaia theory in 1974, much progress has been made in the understanding of how the Earth has the ability to self-regulate. In 1987, Charlson et al. proposed that the emission of dimethylsulfide (DMS) by marine algae could impact local climate through the formation of aerosols and their influence on cloud formation. Over time it has been seen that not only DMS can have effects on the climate, but also other volatile organic compounds (VOCS) such as isoprene and iodomethans play a similar role in the formation of tropospheric aerosols, other sulfur-containing volatiles play a role in the formation of stratospheric aerosols, and bromomethans affect the reactivity of the atmosphere. In marine ecosystems, VOCs fulfill various functions, such as being part of defense strategies, protection against oxidative stress, or communication. In recent years it has been shown that coral reefs are producers of VOCs, but the entire collection of volatiles and the formation processes of many of these compounds within the reef remain to be described, as well as whether these processes are essentially biological (pelagic and benthic) or abiotic (driven by solar radiation and water temperature). To this aim, in this thesis we have studied the VOCs in the internal and external waters of the Mo'orea coral reef, in French Polynesia. This is a well-preserved reef, which is characterized by a virtual unidirectional flow of water and with strong currents, so that it allows to study the connection between the incoming waters, from the open ocean, and the inland waters, influenced by the components and processes of the reef. We have described the spatial and temporal variability of a series of VOCs with climate interest (COS, CS2, isoprene, iodometans (CH3I and CH2ClI), bromometans (CHBr3 and CH2BR2 ) a n d DMS) , a n d n o n - v o l a t i l e re l a t e d c ompo u nds , s u c h a s dimethillefoniopropidated (DMSP), acrylate and dimethylphoxide (DMSO, [CAT] Des que Lovelock i Margulis van introduir la teoria de Gaia l'any 1974, s'ha avançat molt en la comprensió de com la Terra té la capacitat d'autoregular-se. El 1987, Charlson et al. va proposar que l'emissió de sulfur de dimetil (DMS) per les algues marines podria afectar el clima local per mitjà de la formació d'aerosols i la influència d'aquests en la formació de núvols. Amb el temps s'ha vist que no només el DMS pot tenir efectes en el clima sinó que també altres compostos orgànics volàtil (VOCs) com l'isoprè i els iodometans tenen un paper similar en la formació d'aerosols troposfèrics, altres volàtils de sofre tenen un paper en la formació d'aerosols estratosfèrics, i els bromometans afecten la reactivitat de l'atmosfera. En els ecosistemes marins, els VOCs compleixen diverses funcions, com la de formar part d'estratègies de defensa, de protecció contra l'estrès oxidatiu, o de comunicació. En els darrers anys s'ha mostrat que els esculls de corall són productors d'alguns VOCs, però encara queda per descriure tota la col·lecció de volàtils i quins són els processos de formació de molts d'aquests compostos dins de l'escull, si són essencialment biològics (pelàgics i bentònics) o abiòtics (governats per la radiació solar o la temperatura de l'aigua). És per això que en aquesta tesi hem estudiat els VOCs en les aigües internes i externes de l'escull de corall de Mo'orea, a la Polinèsia Francesa. Es tracta d'un escull ben conservat, que es caracteriza per un flux d'aigua pràcticament unidireccional i amb corrents forts, de manera que permet estudiar la connexió entre les aigües entrants, provinents de l'oceà obert, i les aigües interiors, influïdes pels components i processos de l’escull. Hem descrit la variabilitat espacial i temporal d'una sèrie de VOCs d'interès climàtic (COS, CS2, isoprè, iodometans (CH3I i CH2ClI), bromometans (CHBr3 i CH2Br2) i DMS), i compostos relacionats no volàtils, com ara dimetilsulfoniopropionat (DMSP), acrilat i dimetilsulfòxid (

Biogenic volatile organic compounds (VOCs) play key roles in coral reef ecosystems, where, together with dimethylated sulfur compounds, they are indicators of ecosystem health and are used as defense strategies and infochemicals. Assessment and prediction of the exchange rates of VOCs between the oceans and atmosphere, with implications for atmospheric reactivity and climate, are hampered by poor knowledge of the regulating processes and their temporal variability, including diel cycles. Here, we measured the variation over 36h of the concentrations of DMSPCs (dimethylsulfoniopropionate (DMSP)-related compounds, namely DMSP, dimethylsulfoxide, acrylate, dimethylsulfide, and methanethiol as dimethyl disulfide) and VOCs (COS, CS2, isoprene, the iodomethanes CH3I and CH2ClI, and the bromomethanes CHBr3 and CH2Br2), in surface waters inside the shallow, northern coral-reef lagoon of Mo’orea (French Polynesia) and 4 km offshore, in the tropical open ocean. Comparisons with concurrent measurements of sea surface temperature, solar radiation, biogeochemical variables (nutrients, organic matter), and the abundances and taxonomic affiliations of microbial plankton were conducted with the aim to explain interconnections between DMSPCs, VOCs, and their environment across diel cycles. In open ocean waters, deeper surface mixing and low nutrient levels resulted in low phytoplankton biomass and bacterial activity. Consequently, the diel patterns of VOCs were more dependent on photochemical reactions, with daytime increases for several compounds including dissolved dimethylsulfoxide, COS, CS2, CH3I, and CH2ClI. A eukaryotic phytoplankton assemblage dominated by dinoflagellates and haptophytes provided higher cell-associated DMSP concentrations, yet the occurrence of DMSP degradation products (dimethylsulfide, dimethyl disulfide) was limited by photochemical loss. Conversely, in the shallow back reef lagoon the proximity of seafloor sediments, corals and abundant seaweeds resulted

Algal blooms are hotspots of marine primary production and play central roles in microbial ecology and global elemental cycling. Upon demise of the bloom, organic carbon is partly respired and partly transferred to either higher trophic levels, bacterial biomass production or sinking. Viral infection can lead to bloom termination, but its impact on the fate of carbon remains largely unquantified. Here, we characterize the interplay between viral infection and the composition of a bloom-associated microbiome and consequently the evolving biogeochemical landscape, by conducting a large-scale mesocosm experiment where we monitor seven induced coccolithophore blooms. The blooms show different degrees of viral infection and reveal that only high levels of viral infection are followed by significant shifts in the composition of free-living bacterial and eukaryotic assemblages. Intriguingly, upon viral infection the biomass of eukaryotic heterotrophs (thraustochytrids) rivals that of bacteria as potential recyclers of organic matter. By combining modeling and quantification of active viral infection at a single-cell resolution, we estimate that viral infection causes a 2–4 fold increase in per-cell rates of extracellular carbon release in the form of acidic polysaccharides and particulate inorganic carbon, two major contributors to carbon sinking into the deep ocean. These results reveal the impact of viral infection on the fate of carbon through microbial recyclers of organic matter in large-scale coccolithophore blooms

Day-night alternation exerts an obvious rhythmic forcing on photochemical and photobiological processes, which may result in diel oscillations of the chemical-microbe networks, with consequences for biogeochemical fluxes. In the case of the algal metabolite DMSP and the trace gas DMS, previous studies have revealed that their local diel balance in the surface ocean depends on the fine interplay between microbial activities and physical forcing. We investigated the diel patterns in the production and loss rates of DMSP and DMS, sampling in lagrangian mode every 4 hours over 48 hours in open surface waters of the NW Mediterranean Sea. Incubations under natural full light and darkness allowed determination of microbial DMSP consumption rates (radioisotope addition), DMS production and consumption rates (inhibitor addition), and DMS photolysis rates (filtered seawater). These were compared with the variability of bacterial heterotrophic production and the diel transcription patterns of the known relevant genes

The ability of marine bacteria to direct their movement in response to chemical gradients influences inter-species interactions, nutrient turnover, and ecosystem productivity. While many bacteria are chemotactic towards small metabolites, marine organic matter is predominantly composed of large molecules and polymers. Yet, the signalling role of these large molecules is largely unknown. Using in situ and laboratory-based chemotaxis assays, we show that marine bacteria are strongly attracted to the abundant algal polysaccharides laminarin and alginate. Unexpectedly, these polysaccharides elicited stronger chemoattraction than their oligo- and monosaccharide constituents. Furthermore, chemotaxis towards laminarin was strongly enhanced by dimethylsulfoniopropionate (DMSP), another ubiquitous algal-derived metabolite. Our results indicate that DMSP acts as a methyl donor for marine bacteria, increasing their gradient detection capacity and facilitating their access to polysaccharide patches. We demonstrate that marine bacteria are capable of strong chemotaxis towards large soluble polysaccharides and uncover a new ecological role for DMSP in enhancing this attraction. These navigation behaviours may contribute to the rapid turnover of polymers in the ocean, with important consequences for marine carbon cycling

Isoprene contributes to the formation of ozone and secondary organic aerosol in the atmosphere, and thus influences cloud albedo and climate. Isoprene is ubiquitous in the surface open ocean where it is produced by phytoplankton, however emissions from the global ocean are poorly constrained, in part due to a lack of knowledge of oceanic sink or degradation terms. Here, we present analyses of ship-based seawater incubation experiments with samples from the Mediterranean, Atlantic, tropical Pacific and circum-Antarctic and Subantarctic oceans to determine chemical and biological isoprene consumption in the surface ocean. We find the total isoprene loss to be comprised of a constant chemical loss rate of 0.05¿±¿0.01 d-1 and a biological consumption rate that varied between 0 and 0.59 d-1 (median 0.03 d-1) and was correlated with chlorophyll-a concentration. We suggest that isoprene consumption rates in the surface ocean are of similar magnitude or greater than ventilation rates to the atmosphere, especially in chlorophyll-a rich waters., Postprint (published version)

Shallow-water coral reefs hold large quantities of acrylate and its precursor dimethylsulfoniopropionate (DMSP), but production and removal processes for these compounds are poorly characterized. Here we determined the concentrations and cycling of acrylate and DMSP in a transect from a coral reef ecosystem to the open ocean, 2 km beyond the reef in Mo’orea, French Polynesia, during April 2018. Concentrations of dissolved acrylate and DMSP were low throughout the reef-ocean transect, ranging from 0.8–3.9 nM and 0.2–3.0 nM, respectively, with no difference observed between the coral reef and open ocean when comparing mean concentrations (± std dev) of dissolved acrylate (1.7 ± 0.7 vs 2.3 ± 0.8 nM) or DMSP (0.9 ± 0.7 vs 1.3 ± 0.6 nM). In the coral reef, dissolved acrylate was rapidly taken up by the heterotrophic community with a fast turnover time averaging ~ 6 h, six times faster than in the open ocean, and nearly as fast as the average turnover time of dissolved DMSP (~ 3 h). A clear diel trend was observed for the heterotrophic consumption of dissolved acrylate and DMSP in the coral reef, with higher uptake rate constants during daylight hours, synchronized with the larger daytime release of acrylate and DMSP from the coral compared to the nighttime release of these compounds. We also measured photochemical production rates of acrylate in Mo’orean waters, but rates were one to two orders of magnitude slower compared to its rates of biological consumption. Coral and macroalgae were the main sources of dissolved acrylate and DMSP to the reef ecosystem. Our results indicate there is rapid turnover of acrylate and DMSP in the coral reef with a tight coupling between production and removal pathways that maintain dissolved concentrations of these two compounds at very low levels. These algal and coral-derived substrates serve as important chemical links between the coral and heterotrophic communities, two fundamental components in the ecological network in coral reefs

Volatile organic compounds (VOCs) are constituents of marine ecosystems including coral reefs, where they are sources of atmospheric reactivity, indicators of ecosystem state, components of defense strategies, and infochemicals. Most VOCs result from sunlight-related processes; however, their light-driven dynamics are still poorly understood. We studied the spatial variability of a suite of VOCs, including dimethylsulfide (DMS), and the other dimethylsulfoniopropionate-derived compounds (DMSPCs), namely, DMSP, acrylate, and dimethylsulfoxide (DMSO), in waters around colonies of two scleractinian corals (Acropora pulchra and Pocillopora sp.) and the brown seaweed Turbinaria ornata in Mo’orean reefs, French Polynesia. Concentration gradients indicated that the corals were sources of DMSPCs, but less or null sources of VOCs other than DMS, while the seaweed was a source of DMSPCs, carbonyl sulfide (COS), and poly-halomethanes. A focused study was conducted around an A. pulchra colony where VOC and DMSPC concentrations and free-living microorganism abundances were monitored every 6 h over 30 h. DMSPC concentrations near the polyps paralleled sunlight intensity, with large diurnal increases and nocturnal decrease. rDNA metabarcoding and metagenomics allowed the determination of microbial diversity and the relative abundance of target functional genes. Seawater near coral polyps was enriched in DMS as the only VOC, plus DMSP, acrylate, and DMSO, with a large increase during the day, coinciding with high abundances of symbiodiniacean sequences. Only 10 cm below, near the coral skeleton colonized by a turf alga, DMSPC concentrations were much lower and the microbial community was significantly different. Two meters down current from the coral, DMSPCs decreased further and the microbial community was more similar to that near the polyps than that near the turf alga. Several DMSP cycling genes were enriched in near-polyp with respect to down-current waters, namely, the eukary

Isoprene contributes to the formation of ozone and secondary organic aerosol in the atmosphere, and thus influences cloud albedo and climate. Isoprene is ubiquitous in the surface open ocean where it is produced by phytoplankton, however emissions from the global ocean are poorly constrained, in part due to a lack of knowledge of oceanic sink or degradation terms. Here, we present analyses of ship-based seawater incubation experiments with samples from the Mediterranean, Atlantic, tropical Pacific and circum-Antarctic and Subantarctic oceans to determine chemical and biological isoprene consumption in the surface ocean. We find the total isoprene loss to be comprised of a constant chemical loss rate of 0.05 ± 0.01 d−1 and a biological consumption rate that varied between 0 and 0.59 d−1 (median 0.03 d−1) and was correlated with chlorophyll-a concentration. We suggest that isoprene consumption rates in the surface ocean are of similar magnitude or greater than ventilation rates to the atmosphere, especially in chlorophyll-a rich waters

The RETRO-BMC oceanographic cruise was designed to characterize the spatial structures and variability of the Brazil-Malvinas Confluence (BMC) region. The cruise was carried in April 2017 on board the R/V Hespérides, departing from Ushuaia (Argentina) and arriving to Santos (Brazil). There were a total of 33 hydrographic stations, carried out between 13 and 25 April 2017. All stations were offshore from the continental platform and within 42ºS-36ºS and 58ºW-52ºW. Conductivity-temperature-depth (CTD) data were obtained with a SeaBird 911 Plus multi-parametric probe, with redundant salinity and temperature sensors, and additional dissolved oxygen (SBE-43) and fluorescence and turbidity (Wetlabs AFL-NTU-RTD) sensors. Water velocity data was obtained at the stations with a lowered acoustic Doppler current profiler (LADCP) and along the ship’s track with the vessel-mounted ADCP (VADCP). During the entire ship’s track inside the study region, the VADCP gathered velocity data in low-range mode (one velocity profile every 2 min between about 20 and 800 m at 8-m depth bins) and a thermosalinograph gathered salinity and temperature data (every 5 s at a depth of 5 m). The LADCP was attached, together with the CTD, to a 12-liters 24-Niskin-bottle rosette that was used to gather water samples at discrete depths, which were frozen and later analyzed to determine the concentration of inorganic nutrients. In addition, two high-resolution three-dimensional surveys were carried out at the Confluence front with a SeaSoar covering the area between 40.6-39.0°S and 55.6°W-53.8°W. The first transect was completed between the 16 and 17 April, 46 hours covering 620 km, while the second sampled 751 km between the 19 and 21 April 2017, during 52 hours. The SeaSoar was equipped with a SeaBird 911 CTD with the same sensors as in the hydrographic stations, and recorded data in a sawtooth pattern between 5 and 360 m, with a horizontal spacing between apogees of 4 km. Finally, five subsurface drif

The encountering of the subtropical Brazil Current (BC) and the subantarctic Malvinas Current (MC) along the western margin of the Argentine Basin forms the Brazil-Malvinas Confluence (BMC), one of the most intense open-ocean fronts in the world ocean and a site for the formation of intermediate water masses. Here, we provide a comprehensive description of the BMC based on physical and biogeochemical data – hydrographic stations, profiling floats and subsurface drifters – gathered in March 2015. We use these data in order to characterize the impinging and outflowing currents and to describe the cross- and along-frontal thermohaline structure. In addition, we compare the in-situ measurements with both climatological data and the Mercator Ocean eddy-resolving reanalysis. The hydrographic sections illustrate the contrasting properties between the two western boundary currents: warm, salty, nutrient- and oxygen-poor oligotrophic subtropical waters carried southward by the BC and the cold, fresh, oxygen- and nutrient-rich subantarctic waters carried northward by the MC. The frontal system is also characterized by the presence of thermohaline intrusions, with the cross-frontal gradients and along-front velocities sharpening as the colliding currents shape the frontal system. We also observe brackish waters spreading on top of the frontal jet as a result of both the confluence dynamics and off-shelf advection favored by north-easterly winds. These low-salinity waters are positively correlated with surface ageostrophic speeds over the frontal jet. The cruise data illustrates the high regional and mesoscale variability as compared with climatological conditions, and further document the submesoscale subsurface complexity, which is not properly captured by available operational models

Fluorescent Dissolved Organic Matter (FDOM) composition is known to be subjected to modification by multiple processes, both biotic and abiotic. This work examines the combined effect of sunlight exposure and phytoplankton nutritional state on the evolution of FDOM composition along a 23-day mesocosm experiment, carried out at the University of Bergen Mesocosm Centre (Norway) during late spring 2018. The experiment setup consisted on seven 11 m3 bags, three of which were covered with a transparent plastic lid that limited UV-radiation. All bags were enriched with nitrate and phosphate at different ratios and frequency throughout the experiment and the surrounding fjord water was used as a control. Multiple optical parameters were examined daily along with various biogeochemical variables (Chlorophyll-a, DOC and nutrient concentration and phytoplankton composition). Thanks to the experimental design, we were able to attribute changes in FDOM composition to both biotic and abiotic effects. Photobleaching played a major role in the exposed bags, reducing significantly the humic-like components fluorescence (peaks A, C & M), while the production of protein-like components (peaks T & B) was mainly controlled by the nutritional state of the phytoplankton community. Phytoplankton responded to sunlight and nutrient limitation stress by increasing the production of humic-like components as a photoprotection strategy. These findings underline the importance of considering not only environmental and biological factors but also their possible synergetic effects to better understand the forces driving FDOM composition dynamics

This dataset, gathered during the RETRO-BMC cruise, reports multiple-scale measurements at the Confluence of the Brazil and Malvinas Currents. The cruise was carried out between 8 and 28 April 2017 onboard R/V Hespérides, departing from Ushuaia and arriving to Santos. Along its track, the vessel recorded near-surface temperature and salinity, as well as the horizontal flow from 20 m down to about 800 m. A total of 33 hydrographic stations were completed in a region off the Patagonian Shelf, within 41.2°S–35.9°S and out to 53.0°W. At each station, a multiparametric probe and velocity sensors were deployed inside the frame of a rosette used to collect water samples at selected depths; these samples were later used for several water analyses, including inorganic nutrient concentrations. Microstructure measurements were carried out in 11 of these hydrographic stations. In addition, two high-resolution three-dimensional surveys were conducted with an instrumented undulating vehicle between 40.6°S–39.0°S and 55.6°W–53.8°W. Lastly, eight high-frequency vertical profilers were deployed in the region and five position-transmitting drifters were launched. These data allow the description of the Confluence from the regional scale to the microscale, and provide a view of the variability of the frontal region on time scales from days to weeks

Començarem el programa de diumenge a l’Escola Antoni Brusi i veurem com experimenten amb l’aigua i els corrents oceànics com a ‘Petits Oceanògrafs’, un projecte de l’Institut de Ciències del Mar del CSIC

Para hablar sobre InMre, una revista de divulgación científica redactada por investigadores especializados enel mundo marino, Carles Mesa conversa con su creadora, Marta Masteu Navarro, doctoranda del Instituto de Ciencias del Mar (ICM-CSIC) de Barcelona

Hasta hace poco el mundo occidental ha vivido de espaldas al mar, era el vertedero de los países desarrollados. Recientemente la sociedad se ha dado cuenta de que si queremos un futuro mejor para nuestro planeta tenemos que cuidar el océano, y que mejor manera de cuidarlo que conociéndolo. Pero no sirve conocerlo de cualquier forma, es importante que la información que llega a la sociedad sea cierta y fiable. Con éste propósito nace InMare, la revista de divulgación marina redactada por especialistas del sector. Si al creciente interés por el océano le sumamos que hoy en día la divulgación es una pieza clave en la carrera de cualquier científico, tenemos la combinación perfecta. Un espacio a disposición de los científicos para hacer llegar su ciencia a todo el mundo

Satellite infrared radiometers have unveiled the existence of distinct turbulence regimes in the upper ocean. These regimes have different contributions on the vertical transport of nutrients, heat, and climatically important gases between the oceanic upper layers and the ocean interior; and contain information about the dynamics in the mixed layer. The main difficulty is to define descriptors able to univocally identify such turbulence regimes and quantify the dynamical characteristics of the upper ocean. In this study, we have investigated the capability of different descriptors to characterize turbulence regimes from the observations of infrared Sea Surface Temperatures (SST) provided by the AATSR sensor (Envisat). First, data have been divided into granules adapted to the observed cloud coverage with a maximum size of 512 by 512 pixels (i.e. 512 km by 512 km). These granules have been classified into two groups: one characterized by the presence of submesoscale instabilities (~ 5-10 km) and one characterized by the presence of vortices and filaments. Then, for all the granules of each group we have explored the statistical and geometrical properties of SST using spectral analysis and the curvature of SST fronts completed with the analysis of the multifractal properties of SST images obtained from singularity analysis. Results have shown that the both groups of images were characterized by similar spectral slopes. On the contrary, the characteristics of the singularity spectra of both groups were different indicating different inttermitencies and allowing to identify the distinct dynamical regimes

Any ocean perturbation tends towards an equilibrium situation where the vertical balance is hydrostatic and the dominant horizontal forces are pressure gradients and Coriolis force, the so called geostrophic balance. Any motion that represents a desviation from this balance is named ageostrophic. At spatial and temporal scales of order 10-100 km (mesoscale) and longer, these desviations are small except within boundary layers related to the sea-surface wind stress and the sea-bottom friction. At shorter scales (submesoscale), however, they may represent a major part of the motion: these ageostrophic movements correspond to high Rossby values (the ratio of the inertial period, of order 1 day, and the advective time scale) and are usually accompanied by significant vertical motions. The Brazil-Malvinas Confluence (BMC) region is located approximately 200-400 km offshore from Rio de la Plata, where the Brazil Current (BC) and Malvinas Current (MC) collide [1]. This clash leads to the generation of very energetic mesoscale and submesoscale features, as well as to different kinds of propagating waves. During March 2015, the R/V Hespérides sampled the BMC with several high resolution transects of the BMC frontal region (Figure 1), including velocity, temperature and salinity measurements (TIC-MOC cruise). These field data is complemented with data from satellites, the Argo program and the Copernicus operational model. Here we present the results of the data analysis, including the determination of vertical velocities as obtained solving the Omega equation. The BMC turns out to be a region with very energetic ageostrophic motions, characterized by a surface filament and subsurface thermohaline intrusions, as well as substantial vertical velocities

La campaña RETRO‐MC se realizó a bordo del BIO Hespérides con salida de Ushuaia el 8 de abril y llegada a Santos el 28 de abril de 2017. La campaña se hizo en dos fases, una primera fase de 24 horas de trabajo (8 y 9 de abril) en el Canal de Beagle y una segunda fase de 12 días de trabajo (13 a 24 de abril) en la Confluencia de Brasil‐Malvinas

Recent studies have shown that sea surface temperature (SST) and surface wind speed (SWS) are directly related at ocean mesoscales (10-100 km). Here we examine this relationship in the Brazil-Malvinas Confluence region, where we find one of the most intense regional-scale SST gradients in the world's oceans. We analyze SST and SWS collected in situ during an oceanographic cruise done in March 2015. Data is processed to emphasize the variability of SST and SWS associated with oceanic fronts, both at regional and mesoscalar scales, taking into account the latitudinal SST gradients, the passage of atmospheric synoptic disturbances, and the diurnal variability of SWS. We observe that SST has an influence on SWS - a temperature raise of 1ºC involves a wind-speed increase of 0.36 m s-1, with a correlation coefficient of 0.43 and a 95% confidence level - a relationship that is corroborated using wind data from the European Copernicus Project. Finally, we assess the influence of SST on the lower atmosphere through the changes in sensible and latent heat fluxes across the front. The results point at the existence of significant coupling between the upper ocean and the lower atmosphere

Estudis recents han demostrat que, a escales oceàniques mesoescalars (10-100 km), existeix una relació directe entre la temperatura superficial de l’oceà (SST) i el vent en superfície. En aquest estudi s’examina aquesta relació en la regió de Confluència de Brasil-Malvines (CBM), que és una de les conques oceàniques amb els gradients d’SST més intensos, mitjançant l’anàlisi de dades in-situ d’SST i vent en superfície recollides durant una campanya oceanogràfica realitzada el març del 2015. Les dades són curosament tractades per tal d’emfatitzar la variabilitat d’SST i vent associades a les estructures mesoescalars, tenint en compte els gradients latitudinals d’SST a gran escala, el passatge de pertorbacions sinòptiques atmosfèriques i la variabilitat diürna del camp de vents. Després de minimitzar tots aquests efectes, s’observa que l’SST efectivament influencia el vent en superfície, de -1 manera que un augment d’SST en 1°C comporta un increment en el vent superficial de 0,36 m s , amb un coeficient de correlació de 0,43 amb un 95% d’interval de confiança. Podem concloure que en zones frontals intenses, com ara la regió de CBM, existeixen mecanismes complexes d’acoblament entre l’oceà i l’atmosfera