Dataset on the RETRO-BMC cruise onboard the R/V Hespérides, April 2017, Brazil-Malvinas Confluence

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

Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Malvinas Current temporal variability and its relationship with water masses in the Southwestern Atlantic

La corriente de Malvinas (CM) está ubicada en el Atlántico Sudoccidental, sobre el talud continental patagónico (TCP). La CM fluye hacia el norte siguiendo el contorno del talud a lo largo de unos 1800 kilómetros hasta aproximadamente 38°S, donde se encuentra con la Corriente de Brasil. El encuentro de ambas corrientes genera la región conocida como Confluencia Brasil-Malvinas (CBM). La CM es la corriente del hemisferio sur que transporta aguas frías subpolares más cerca del ecuador, siendo ésta, una de sus características más relevantes. Asimismo, contribuye al transporte de calor y sal entre distintas latitudes. En su camino hacia el norte, la CM transporta aguas ricas en oxígeno y nutrientes. El oxígeno y los nutrientes se utilizan a lo largo del talud y son los responsables de la gran biomasa de fitoplancton observada en la región. La gran productividad característica del talud se propaga a través de la cadena alimentaria, dando lugar a importantes pesquerías en la región. Las mediciones in-situ registradas sobre la CM se han colectado principalmente en su porción norte, en 40°-41°S, muy cerca de la CBM. El estudio de la CM en dicha región se ve afectado por la variabilidad estacional que caracteriza la CBM. La presente tesis doctoral tiene como objetivo general comprender la variabilidad temporal de la corriente de Malvinas y la estructura de las masas de agua presentes en el talud continental. Para alcanzar dicho objetivo, analizamos los siguientes datos: in-situ, colectados en el marco del proyecto CASSIS (Corrientes del Atlántico Sudoccidental Satélite In Situ, www.cima.fcen.uba.ar/malvinascurrent), hidrográficos históricos registrados en la región y remotos, obtenidos a partir de satélites que miden la altura y la temperatura superficial del mar. El conjunto de datos in-situ se obtuvo a partir de distintos instrumentos que estuvieron fondeados sobre el TCP en 40°-41°S y en 44,7°S entre diciembre 2014 y junio 2017. Las variables oceanográficas analizadas en esta tesis son: temperatura potencial (θ), salinidad (S), presión (P), componente zonal (u) y meridional (v) de la velocidad. La observaciones in-situ colectadas sobre la CM en 40°-41°S entre diciembre 2014 y noviembre 2015 mostraron dos regímenes que denominamos fuerte y débil. Durante el régimen fuerte la CM fluye a lo largo del talud continuamente a través de los fondeos hacia el noreste, mientras que durante los casi 5 meses de duración del régimen débil se presentan con frecuencia reversiones de las velocidades a lo largo del talud. La comparación del nuevo set de datos con series temporales de velocidades registradas durante las últimas tres décadas, en la misma región, muestra que es la primera vez que se observa un período tan extenso de flujo débil. Durante el régimen débil, se observa la presencia de Aguas Modales Subantárticas sobre la isobata de 1800 m a una profundidad promedio de 500 m. Las masas de agua que ocuparon los primeros 1600 m en la columna de agua durante el período fuerte, se hundieron y desplazaron hacia el este durante el período débil. Las velocidades geostróficas y la temperatura superficial del mar muestran claramente que el régimen débil se generó debido a una desviación hacia el este de la CM, aguas arriba de la posición de los fondeos. Las mediciones de corrientes in-situ sobre la CM obtenidas en 44,7°S, entre diciembre 2015 y junio 2017, muestran una corriente con una estructura barotrópica que fluye en dirección norte a lo largo de las isobatas. Las velocidades meridionales registradas en los fondeos Oeste y Este no están correlacionadas. Las mismas muestran oscilaciones de gran amplitud que son coherentes con el pasaje de estructuras de mesoescala sobre los fondeos. Los datos de altimetría satelital, que están altamente correlacionados con los datos de velocidades in-situ filtrados a 20 días (r ~ 0,80), sugieren que la variabilidad de la CM es afectada por anomalías del nivel del mar (ANM) que se propagan a lo largo del talud con velocidades de fase que oscilan entre 0,21 ± 0,04 m s^-1 y 0,14 ± 0,01 m s^-1. Las ANM se propagan hacia el norte siguiendo contornos de vorticidad potencial planetaria a lo largo del talud y sus velocidades de fase disminuyen hacia el este. Las ANM que llegan a 44,7°S podrían originarse al norte de la placa de Scotia y en ~50°S a lo largo de la Escarpa de Malvinas, entre 47,2°O y 39,6°O. A partir de los resultados obtenidos se sugiere que la interacción entre las corrientes y la compleja batimetría en dichas regiones genera inestabilidades que potencian la generación de estructuras de mesoescala que se propagan en la dirección del flujo a lo largo del borde Oeste de la cuenca Argentina, afectando la variabilidad de las velocidades en la CM. Las velocidades de fase observadas en las ANM no corresponden a las velocidades de fase características de ondas atrapadas al talud descriptas en otras regiones. Las periodicidades características de las ANM mencionadas, fueron también observadas en los datos de temperatura potencial registrados por los instrumentos en 44,7°S. Velocidades geostróficas calculadas a partir de datos hidrográficos obtenidos entre el 8 y 10 de junio 2017, muestran que el flujo de la CM en 44,7°S está caracterizado por la presencia de 2 jets principales. A diferencia de los resultados encontrados en 40o-41°S, en 44,7°S no se observa una clara relación entre la variabilidad de la CM y la estructura de las masas de agua presentes en el talud. Un análisis de coherencia realizado combinando las series temporales de u y v versus θ y S derivadas de las mediciones colectadas cerca del jet principal de la CM en 760 m y en 1042 m de profundidad, mostró coherencias significativas entre las variables analizadas alrededor de 52, 25 y 15 días sólo en ~760 m. Este trabajo de investigación aumenta nuestro conocimiento acerca de la dinámica de la CM. Mejorar la comprensión de la circulación en la cuenca Argentina es un importante punto de partida para poder comprender los procesos físicos que sustentan los ricos ecosistemas presentes en el TCP en futuros trabajos.The Malvinas Current (MC) is located in the Southwestern Atlantic, on the Patagonian slope (PS). The MC flows northward following the contour of the slope for about 1800 kilometers to approximately 38°S, where it meets the Brazil Current (BC). The meeting of both currents generates the region known as the Brazil-Malvinas Confluence (BMC). The MC is the southern hemisphere current that transports subpolar cold waters to the equator. Thus, it contributes to the heat transport between different latitudes. In addition, the MC carries waters rich in oxygen and nutrients. Oxygen and nutrients are used along the slope and are responsible for the large phytoplankton biomass observed in the region. The high productivity characteristic of the slope spreads through the food chain and thus supports important fisheries in the region. In situ measurements along the MC have been collected mostly in its northern portion at 40°-41°S. The study of the MC in this region is affected by the seasonal variability that characterizes the BMC. This doctoral thesis has the general objective of understanding the MC temporal variability and the water masses structure present in the PS. To achieve this objective, we analyzed unpublished in situ currents data obtained in the framework of the French-Argentine CASSIS project (www.cima.fcen.uba.ar/malvinascurrent), historical hydrographic and altimetry data collected in the region. The unpublished in situ data set was registered from different instruments that were anchored across the MC at 40°-41°S and at 44,7°S between December 2014 and June 2017. The oceanographic variables analyzed in this thesis were: potential temperature (θ), salinity (S), pressure (P), zonal (u) and meridional (v) velocity components. The in situ observations collected across the MC at 40°-41°S between December 2014 and November 2015 showed two different regimes that we called strong and weak. During the strong regime the MC flows northeast through the moorings while during the nearly 5 months long weak regime reversals of along-slope velocities are frequently observed. Comparison between the new data set with the previous in situ time series registered during the last three decades in the same region shows that such an extended period of weak flow has not been previously observed. During the weak regime, Sub-Antarctic Mode Water is observed over the 1,800 m isobath at an average depth of 500 m. Water masses occupying the upper 1,600 m during the strong regime deepen and shift eastward during the weak period. Satellite geostrophic velocities and sea surface temperature clearly show that the weak regime is due to a deflection to the east of the MC, upstream of the mooring position. In situ current measurements obtained across the MC at 44.7°S between December 2015 and June 2017 show a current with an equivalent-barotropic structure that flows northward along the isobaths. The meridional velocities at the western and eastern moorings are not correlated and show large amplitude oscillations which are coherent with the passage of mesoscale features over the moorings. Satellite altimetry data, that are highly correlated with 20-day low-pass filtered in situ velocities (r~0.80), show that the MC variability is affected by the propagation of sea level anomalies (SLA) along the Patagonian slope with phase speeds that range between 0.21 ± 0.04 m s^-1 and 0.14 ± 0.01 m s^-1. SLAs propagate northward along the slope following contours of constant planetary potential vorticity and its phase speeds decrease towards the east across the slope. SLA arriving at 44.7°S could originate in the northern flank of the North Scotia Ridge and ~50°S along the Malvinas Escarpment between 47.2°O y 39.6°O. We suggest that the interaction between the currents and the complex bathymetry at those locations generate instabilities that enhance the generation of mesoscale structures that propagate in the flow direction along the western boundary of the Argentine Basin affecting the variability of the MC velocities. The phase speeds of the SLAs observed do not correspond to the phase speeds characteristic of the shelf-break trapped waves described in other regions. The characteristic periodicities of the SLAs were also observed in the potential temperature data registered by the instruments at 44.7°S. Geostrophic velocities calculated from hydrographic data collected between December 2015 and June 2017 show that the MC flow at 44.7°S is characterized by the presence of 2 main jets. Unlike the results found at 40°-41°S, at 44.7°S, a clear relationship between the MC variability and the structure of the water masses present on the slope is not observed. A coherence analysis carried out combining the time series of u and v versus θ and S derived from the measurements collected near the main jet of the MC at 760 m and at 1042 m depth, showed significant coherence between the variables analyzed around 52, 25 and 15 days only in 760 m depth. This research work increased our knowledge about the dynamics of the MC. Improving the understanding of the circulation in the Argentine basin is important to understand the physical processes that sustain the rich ecosystems present in the Patagonian slope in future works.Fil: Paniagua, Guillermina Fernanda. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Malvinas current at 44.7°S: First assessment of velocity temporal variability from in situ data

International audienceWe report current meter measurements obtained by four moorings deployed across the Malvinas Current (MC) at 44.7ºS during 18 months between December 2015-June 2017. Previous measurements of the MC strength have been reported only close to the Brazil-Malvinas Confluence, hindering the interpretation of the flow variability. The record-length time averaged velocities and variance ellipses indicate a strong northward along-isobath flow with an equivalent-barotropic structure. The meridional velocities at the western and eastern moorings are not correlated and show large amplitude oscillations which are coherent with the passage of mesoscale features over the moorings. Satellite altimetry data, that are highly correlated with 20-day low-pass filtered in situ velocities (r~0.80), show that the MC variability is affected by the propagation of sea level anomalies (SLA) along the Patagonian slope with phase speeds that range between 0.21 ± 0.04 m s-1 and 0.14 ± 0.01 m s-1. SLAs propagate northward along the slope following contours of constant potential vorticity and its phase speeds decrease towards the east across the slope. SLAs that mostly affect the western mooring originate in the northern flank of the North Scotia Ridge while SLAs that mostly affect the eastern mooring originate along the Malvinas Escarpment, along the northern edge of the Malvinas Plateau. We suggest that the interaction between eddies and the complex bathymetry at those locations generate instabilities that enhance the generation of mesoscale structures that propagate in the flow direction along the western boundary of the Argentine Basin affecting the variability of the MC velocities

Malvinas Current at 40°S–41°S: first assessment of temperature and salinity temporal variability

International audienceThe temporal variability of 11 months of in situ velocity, temperature, and salinity data collected at five moorings deployed at 40°S–41°S across the shelf-break in the Southwestern Atlantic is analyzed. Two distinct regimes characterized by strong and weak along-slope velocities are present. During the strong regime the Malvinas Current flows northward through the moorings while during the nearly 5months long weak regime reversals of the along-slope velocities are frequently observed. Comparison with the previous in situ time series obtained in the same region shows that such an extended period of weak flow has not been previously observed. During the weak regime, Sub-Antarctic Mode Water is observed over the 1,800 m isobath at an average depth of 500 m. Water masses occupying the upper 1,600 m during the strong regime deepen and shift eastward during the weak period. Satellite geostrophic velocities and sea surface temperature clearly show that the weak regime is due to a deflection to the east of the Malvinas Current, upstream of the mooring position. Analysis of the vertical structure of the currents indicate that during the weak regime the flow weakens mostly at the surface and presents a very small vertical shear. In contrast, during the strong regime currents are surface-intensified. The change in the structure of the cur-rents at the mooring location impacts the relationship between in situ and altimetry-derived currents: during the weak regime altimetry adequately represents (rmsd 12 cm/s) in situ currents in the whole water column, while during strong regime rmsd are larger than 15 cm/s below 600 m depth

On the Wind Contribution to the Variability of Ocean Currents Over Wide Continental Shelves: A Case Study on the Northern Argentine Continental Shelf

International audienceThe southwestern Atlantic Ocean has one of the largest and most productive continental shelves of the southern hemisphere. Despite its relevance, its circulation patterns have been largely inferred from hydrographic observations and numerical models. Here we describe the variability of the shelf circulation based on the analysis of 11 months of multilevel currents measured by two bottom-mounted acoustic Doppler current profilers deployed over the continental shelf at 39°S. The record-length mean is 12 and 13 cm/s in the upper layer and decreases to 6 and 8 cm/s near the bottom, at the deployment nearer and further from the coast, respectively. The mean flow direction is toward the NE, following the orientation of the isobaths. Measurements at both sites show that the alongshore barotropic component accounts for 83% of the variability observed and are well correlated (0.86), suggesting a relatively uniform flow, which is presumably driven by large-scale forcing. Indeed, large-scale wind stress patterns dominate the temporal variability of the in situ currents and the passage of atmospheric fronts induces significant changes in the observed currents at all depths. We found that for 12% of the measurements the currents reverse the direction to the SW in response to these atmospheric patterns. Furthermore, the analysis of sea surface height reconstructed from bottom pressure measurements at both sites and from a coastal tide gauge reveals that the variability of the alongshore currents is driven by the cross-shore pressure gradients generated by the alongshore wind stress

Argentine continental shelf currents 2015-2017 from upward-looking ADCPs

Zonal and meridional velocities each 4 m in the vertical from upward-looking ADCPs with a 30 minutes temporal resolution measured in two locations of the Argentine continental shelf along 44.7°S from 2015 to 2017 (several papers under review).Fil: Saraceno, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Provost, Christine. Sorbonne University; FranciaFil: Piola, Alberto Ricardo. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval. Departamento Oceanografía; ArgentinaFil: Guerrero, Raul Alfredo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Ferrari, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Paniagua, Guillermina Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Lago, Loreley Selene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Artana, Camila Indira. Sorbonne University; Franci

Malvinas Current 2015-2017: Mooring velocities

This study is a contribution to the CASSIS MALVINAS CURRENT project, funded by EUMETSAT/CNES DSP/OT/07-2118 and DSP/OT/07-4571, CONICET-FYPF PIO 133-20130100242. We particularly thank the support of the following institutions: SHN, Mincyt, INIDEP, CONICET, UBA, Prefectura Naval Argentina, Puerto Deseado crew, CNRS, Sorbonne Université LOCEAN, LOPS and DT-INSU.Fil: Saraceno, Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: provost, christine. No especifíca;Fil: Piola, Alberto Ricardo. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Guerrero, Raul Alfredo. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Ferrari, Ramiro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Paniagua, Guillermina Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Lago, Loreley Selene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Artana, Camila Indira. No especifíca

Zooplankton community modulated by spatial and tidal changes in the Bahía Blanca Estuary, Argentina

The variability of the zooplankton community over a spatial and a tidal scale, the relationship between physico-chemical variables, and the abundance of zooplankton were studied in the temperate and turbid Bahía Blanca Estuary (Southwestern Atlantic, Argentina). Samples were taken by pumps during 12-h tidal cycles, at 3-h intervals, from two depths and three sites across the main channel in the inner and middle estuary zones. The zooplankton was dominated by the copepods Acartia tonsa and Euterpina acutifrons, and larvae of the invasive Pacific oyster Crassostrea gigas. The physico-chemical variables that most influenced the zooplankton community were salinity, temperature, suspended particulate matter, and chlorophyll a Most taxa showed higher abundances in the inner estuary, which corresponds to a turbid and shallow area. The abundance of A. tonsa was higher in the inner estuary while that of E. acutifrons was higher in the middle estuary. This spatial distribution is consistent with the tidal distribution of these species as in the inner estuary the abundance of A. tonsa peaked at ebb tide and that of E. acutifrons peaked at flood tide. Significant differences in the zooplankton community structure both across the channel and between depths were detected by multivariate analyses, but no clear patterns were found in the abundance of each taxon by a species-level analysis. The results provide insight into the patterns of zooplankton distribution and abundance in a temperate, turbid, and human-impacted coastal ecosystem, considering different spatial and short-term scales. These results will be useful to design efficient sampling programmes in highly dynamic environments.Fil: Chazarreta, Carlo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Dutto, María Sofía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Berasategui, Anabela Anhi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Paniagua, Guillermina Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Centro de Investigaciones del Mar y la Atmósfera. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Centro de Investigaciones del Mar y la Atmósfera; ArgentinaFil: Fritz, Laura Jesica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Cuadrado, Diana Graciela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; ArgentinaFil: Hoffmeyer, Monica Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentin