The South American Climate Change (SACC) Consortium is an initiative sponsored by the IAI through the Cooperative Research Networks (CRN) Program.
The GENERAL PURPOSE of the SACC Consortium is:
To coordinate and enhance human and institutional resources in South American countries, in order to advance the understanding of the coupled effects of global change and climate variability on the oceanic, atmospheric and terrestrial ecosystems of the Western South Atlantic region.
general(see all news) Aug - 14 - 2014 Dr. Hermes W. Mianzan We greatly regret to inform that our dear friend, colleague and co-PI of CRN2076, SGP2076 and CRN3070 Dr. Hermes W. Mianzan passed away on 9 July 2014. Hermes was a delightful person to work with and throughout his career mentored a large number of students in Argentina and abroad. His work spanned from the study of jelly fish to multidisciplinary research of ocean fronts and from subantarctic waters in the southwest Atlantic to global scale problems. His broad view of marine science was unique. Te extrañamos.
general(see all news) Mar - 14 - 2014 Short Course at UBA Biogeochemical cycles in highly productive marine ecosystems by Michele Graco (IMARPE, Peru) and invited professors Marcelo Acha (INIDEP/CONICET), Alejandro Bianchi (SHN/UBA), Laura Bianucci (U. Dalhousie), Elbio Palma (UNS/ISAD/CONICET) and Martin Saraceno (UBA/CIMA/CONICET).
The course reviewed the basis of the biogeochemical process in the ocean and presented examples of highly productive regions focused on the coastal upwelling system off Peru and on the physical and biophysical process on the Patagonian Continental Shelf and Shelf-Break marine ecosystems.The Course was attended by 28 students from Argentina, Brazil, Chile, Peru and Uruguay. Co-sponsored POGO and Universidad de Buenos Aires.
general(see all news) May - 25 - 2013 Multiple Jets A study published in J. Geophysical Research - Oceans by Piola and co-authors proposes that the Malvinas Current is formed by multiple jets. The jets are distinct features of the strong Malvinas Current north of about 50ºS.
Piola, A. R., B. C. Franco, E. D. Palma, y M. Saraceno, 2013, Multiple jets in the Malvinas Current, J. Geophys. Res. Oceans, 118, 2107-2117, doi:10.1002/jgrc.20170.
from the field(see all news) Oct - 18 - 2013 Subtropical Shelf Front cruise completed successfully 12 October 2013
R/V Puerto Deseado (CONICET, Argentina) arrived today in Mar del Plata after successfully completing the field work for the Subtropical Shelf Front survey. The cruise was designed to monitor the export of shelf waters along the STSF and the planktonic species involved. We occupied 55 hydrographic stations including quasi-continuous vertical profiles of temperature, salinity, dissolved oxygen and fluorescence, and collection of water samples for salinity, dissolved oxygen, nutrients, chlorophyll and smaller fractions of phytoplankton. Each profile included current measurements with an acoustic Doppler current meter (ADCP). Twenty five oblique plankton net casts were also obtained. Underway observations included ADCP as well as surface temperature and salinity observations.
Preliminary results allow us to observe Rio de la Plata and distinct varieties of shelf waters being expelled off shelf along the axis of the energetic Brazil-Malvinas Confluence.
from the field(see all news) Oct - 2 - 2013 Multidisciplinary cruise begins today The argentine vessel Puerto Deseado departs this afternoon from Mar del Plata to begin a multidisciplinary research cruise to obtain physical, chemical and biological data in the region of the Subtropical Shelf Front. This region is presumably an export route of subtropical and subantarctic shelf waters to the open ocean. The cruise plan includes fifty seven hydrographic stations and plankton net deployments in Argentine, Uruguayan and Brazilian waters. The scientific crew includes scientists and students from Servicio de Hidrografia Naval, INIDEP and Universidad de Buenos Aires (Argentina), FURG (Brazil) and Universidad de la Republica (Uruguay).
general(see all news) Jun - 11 - 2013 New SACC Short Course Biogeochemical cycles in highly productive marine ecosystems
Buenos Aires, 2-14 December 2013
Professor: Michelle Ivette Graco (IMARPE, Peru)
The course is co-sponsored by the Scientific Committee on Oceanic Research, Universidad de Buenos Aires and IAI-CRN3070
More information in
from the field(see all news) Dec - 21 - 2012 New Cruise completed on R/V Alpha-Crucis The 8th SAM cruise was carried out 1-16 December 2012 on board R/V Alpha-Crucis (IOUSP/Brazil). The cruise included a full-depth hydrographic section across the South Atlantic western boundary current, data telemetry from four Pressure Inverted Echosounders (PIES) and deployment at three new sites at 34.5S. These observations are designed to study the variability of the western boundary current transport, a key contributor to the export of deep waters from the Atlantic Ocean and the Atlantic Meridional Circulation (see http://www.aoml.noaa.gov/phod/SAMOC_international/index.php). In addition, we carried out the third occupation of a hydrographic section across the southern Brazil continental shelf, spanning the slope, the Subtropical Shelf Front (STSF) and the Plata plume. These observations are designed to test the hypothesis that the STSF is a main conduit for the export of shelf waters to the deep ocean. See "Export of shelf waters ..." news below (7 May 2012).
from the field(see all news) Jul - 12 - 2012 New SAM cruise completed The 7th SAM cruise was carried out 2-11 July 2012 on board R/V Puerto Deseado (CONICET, Argentina). The cruise included a full-depth hydrographic section across the South Atlantic western boundary current and data telemetry from four Pressure Inverted Echosounders (PIES) at 34.5S. These observations are designed to study the variability of the western boundary current transport, a key contributor to the export of deep waters from the Atlantic Ocean and the Atlantic Meridional Circulation (see http://www.aoml.noaa.gov/phod/SAMOC_international/index.php).
In addition a hydrographic section across the southern Brazil continental shelf, spanning the slope, the Subtropical Shelf Front (STSF) and the Plata plume was occupied. These observations are designed to test the hypothesis that the STSF is a main conduit for the export of shelf waters to the deep ocean. See "Export of shelf waters ..." news below (7 May 2012).
from the field(see all news) May - 10 - 2012 SAM Cruises in the SW South Atlantic Six research cruises have been carried out across the Brazil Current off southern Brazil (34.5ºS). The SAM 05 cruise also included a hydrographic section across the continental shelf. These cruises were carried out by scientists and students from Servicio de Hidrografía Naval (AR), Universidade Federal do Rio Grande (BR), Universidade de Sao Paulo (BR) and Universidad de Buenos Aires (AR).
general(see all news) May - 7 - 2012 Export of shelf waters along the Subtropical Shelf Front: A one way ticket? The IAI has approved a Follow-up extension of CRN2076.
The goal of this research is to determine the mechanisms responsible for the export of shelf waters to the deep ocean and its biological and biogeochemical implications.
Our previous work leads us to believe that the STSF is a preferential site for the detrainment of shelf waters onto the deep ocean. Our studies indicate that deep-ocean waters entrained along the Patagonian and Brazilian shelves are funneled towards this front where they are fluxed offshore. In this CRN2 follow-up we propose to test this hypothesis and some of its biological and biogeochemical implications which may globally significant.
PIs: Alberto R. Piola (AR), H.W. Mianzan (AR), Edmo J.D. Campos (BR), José H. Muelbert (BR), Osmar Moller Jr. (BR), Oscar Pizarro (CL), Ken Brink (USA), Ricardo Matano (USA), Marcelo Barreiro (UY)
documents(see all news) Dec - 26 - 2011 Understanding hake larvae Small planktonic fish larvae are vulnerable to dispersion by turbulent and energetic ocean currents. The hake fishery, the most significant catch in Patagonia depends on the success of larvae survival, and in this region larvae are particularly vulnerable to the strong tidal currents and prevailing winds. It appears that by vertically migrating in the water column hake larvae are able to remain close to their food supply for long enough time to grow. A study lead by Gustavo Alvarez Colombo combines hydroacoustic and in-situ data, together with hydrographic data and numerical simulations to display the larvae distribution patterns and their variability and how the vertical migrations are coupled with the vertical stratification and the circulation.
from the field(see all news) Dec - 23 - 2011 Gear acquired by FURG The Oceanographic Institute at FURG has recently acquired an undulating vehicle for collecting crucial physical and biogeochemical data from an underway vessel. This vehicle will allow the collection of observations with much finer spatial resolution than conventional profiling instruments, which is particularly necessary around ocean fronts.
Here Osmar Moller proudly stands by the new Acrobat during tests conducted off New Bedford, MA. The instrument is manudatured by Sea Sciences, Inc.,
general(see all news) Dec - 23 - 2011 PhD Thesis defended at University of Paris Alejandro Bianchi (SHN/UBA) defended his PhD thesis at University of Paris. His research is focused on the sea-air CO2 fluxes in the Patagonia continental shelf based on shipborne observations, and on how these fluxes depend on the environmental variables and physical and biological processes.
general(see all news) Dec - 21 - 2011 SACC at COP-17 Edmo Campos and Alberto Piola, together with Pedro Monteiro (CSIR, South Africa), Christopher Sabine (NOAA/PMEL, USA) and Ione Anderson (IAI) integrated the panel during a side event organized by IAI during the 17th Conference of the Parties (COP17) to the United Nations Framework Convention on Climate Change (UNFCCC).
general(see all news) Oct - 21 - 2011 POSITION ANNOUNCEMENT The Universidade Federal do Rio Grande (FURG) - Instituto de Oceanografia /Rio Grande-RS announces the opening of two teaching positions at the Adjunct Professor level in the fields of Marine Geology and Physical Oceanography.
Applications open between 24 October and 7 November 2011
Details can be found at http://www.sarh.furg.br/arquivos/editais/002846.pdf
A UNIVERSIDADE FEDERAL DO RIO GRANDE-FURG/ Instituto de Oceanografia /Rio Grande-RS abre Concurso para Professor Adjunto nas áreas de:
GEOLOGIA GERAL (1 vaga) e OCEANOGRAFIA FÍSICA (1 vaga) .
INSCRIÇÕES: de 24/10/2011 até 07/11/2011
O Edital completo pode ser acessado em: http://www.sarh.furg.br/arquivos/editais/002846.pdf
fellowships(see all news) Apr - 15 - 2011 Graduate thesis defended at UBA Laura A. Ruiz Etcheverry presented his graduate dissertation entitled Sobre la utilización de los datos de altimetría satelital en la Plataforma Continental Argentina. The work was carried out at Universidad de Buenos Aires, Argentina, under the advise of Dr. Martín Sarraceno.
fellowships(see all news) 14 Sep 2010 Graduate thesis defended at UBA Ramiro Ferrari presented his graduate dissertation entitled Clasificación de masas de agua a partir de sus propiedades ópticas al Norte de 37ºS en el Atlántico Sudoccidental. The work was carried out at Universidad de Buenos Aires, Argentina, under the advise of Dr. Silvia Romero. Ramiro is going to persue his doctoral degree at Université de Paris (VI).
fellowships(see all news) 02 Sep 2010 Masters Thesis defended at FURG Paula Costa Campos presented her Master´s dissertation entitled Oceanographic variability in Santa Marta Cape. The work was carried out at Universidade Federal do Rio Grande (FURG), Brazil, under the advise of Dr. Osmar Moller Jr.
fellowships(see all news) 19 Feb 2008 Drifting away... UPDATED SEP2009
Surface drifters provide the best direct observations of the surface circulation on a global scale. Uriel Zajaczkovski used drifters to estimate horizontal diffusivities in the South Atlantic, and their relation to the general circulation. Uriel is currently a graduate student at Scripps Institution of Oceanography.
fellowships(see all news) 09 Jan 2008 News from Tallahassee UPDATED AUG 2009
Jose Luiz Azevedo completed his doctoral degree at FURG, Brazil under the advise of M. Mata (FURG) and D. Nof (FSU, USA). Ze Luiz holds a teaching position at FURG.
Jose Luiz has worked with models designed to understand the role of Agulhas rings arriving at the western boundary of the South Atlantic on the transport of the Brazil Current, and how this process may impact on the detachment of eddies in the Brazil-Malvinas Confluence (BMC). The BMC presents one of the most energetic mesoscale fields in the World Ocean. As illustrated in the Figure below, among other effects, BMC eddies significantly enhance the ocean productivity in the SW Atlantic, which also spreads eastward towards the basin interior.
from the field(see all news) 09 Feb 2009 Ocean Mixing R/V Roger Revelle is conducting a purposeful tracer experiment in the SE Pacific as part of the DIMES project. For more information follow: http://dimes.ucsd.edu/
from the field(see all news) 21 Dec 2008 Valdes Front survey R/V Capitan Canepa from Instituto Nacional de Investigacion y Desarrollo Pesquero has completed a survey of the Valdes Front. The Valdes front, the interface between well mixed coastal waters and stratified mid-shelf waters, is a productive hotspot in the northern Patagonia summers.
Members of the SACC-C project carried out a cruise to the Península Valdés region (Patagonia) on the research vessel B.I.P. Capitán Cánepa (INIDEP) between 12 and 22 December 2008. The cruise had financial support from the Instituto Nacional de Investigación y Desarrollo Pesquero (INIDEP), and its main objective was to obtain a snapshot of biological and physical processes at a tidal front. The high tidal energy dissipation in this region generates a strong and productive front, where also red-tide episodes occur frequently. Previous studies focused separately on frontal physics and/or biology, but there was a lack of a joint view on bio-physical relationships.
Samples and measurements during the cruise were obtained along a cross-front transect covering the homogeneous, transitional, and stratified regions of the tidal front. The transect was performed twice, during daytime and night, in order to study vertical migrations along a daily cycle. Tasks on board included physical oceanography (CTD; thermosalinographer); water sampling (niskin bottles) for photosynthetic pigments, nutrients and bacteriological studies; acoustic records (200 KHz) to study plankton and fish distributions; stratified sampling (multi-net) for micro- and mesozooplankton; hyperbenthos sampling (plankton sledge); benthos sampling (grab); and juvenile fishe (mini-trawl). Specimens from different communities were collected to describe the trophic web using N and C stable isotopes, and to study putative toxicity due to red-tides. Studies will be performed by several research groups from INIDEP and Universidad Nacional de Mar del Plata (Argentina). The final product of this cooperative effort will be a conceptual model of the frontal functioning.
from the field(see all news) 14 Dec 2008 Chasing coccolitophores in Patagonia R/V Roger Revelle is sailing in good weather conditions on the Patagonia shelf searching for coccolitophores. Silvia Romero (SHN/UBA/AR) and Daniel Valla (undergraduate student UBA/AR, photo) are participating in the expedition.
The cruise is led by Dr. William (Barney) M. Balch from the Bigelow Laboratory of Ocean Sciences and includes various ancillary components, with participation of scientists from several fields of oceanography. Please visit http://www.bigelow.org/about/senior-research-scientists/balch.php
To learn more about the expedition visit http://www.bigelow.org/docs/Balch%20%23%20OCE-0728582.pdf
Take a fresh look at R/V Roger Revelle activities:
from the field(see all news) 02 Nov 2007 Acoustic jelly fish survey Hermes Mianzan and Marcelo Acha (INIDEP) visited the Dauphin Island Sea Lab to conduct a survey of jelly fish in collaboration with William Graham. Increased jelly fish abundance, reported in several marine ecosystems is though to be a consequence of overfishing.
The survey, carried out 5-13 October, was designed to investigate the behavior of jelly fish and aggregations around fronts in the Mobile Bay estuary. Adrian Maridolas and Gustavo Alvarez Colombo, who use acoustic methods to track marine species at INIDEP also participated in the survey.
The research cruises were carried out on R/V E. O. Wilson using a SIMRAD EY500 portable echosounder and a 38 kHz split-beam transducer. The study focused on the distribution of Aurelia sp., surveying along transects and occupying fixed stations. On stations, a video camera was mounted jointly with the echosounder to corroborate the identification of the acoustic targets. Results are being analyzed at INIDEP and Dauphin Island Sea Lab. We look forward to learn about the findings fo this exciting research and to further applications in the western South Atlantic.
from the field(see all news) 31 Oct 2007 Mooring deployment off Rio Grande Osmar Moller reports from Rio Grande
Mooring deployment off Rio Grande
An acoustic current profiler (ADP) Sontek 1,0MHz was deployed at 25 m depth at 32o 14.9 S - 051 o 45.1W on 10 October as part of SACC’s observing program. The area known as “Parcel do Carpinteiro” is a reef which of irregular bottom topography formed by beach rocks, gravel and sand, avoided by trawlers. The ADP was installed within a Floatation Technology Trawl Resistant Bottom Mount and fitted with a Benthos acoustic release.
The ADCP is fitted with temperature and pressure sensors and was set to record current velocity and direction in 1 m height cells. Every vertical profile corresponds to the average of 120 pings emitted during 2 minutes. The operation was carried out with the research vessel “Atlântico Sul” from FURG with the participation of Argentinean researchers from INIDEP coordinated by SACC. Raul Reta and Alvaro Cubiella participated in the deployment cruise and visited FURG to learn about the mooring design and deployment efforts being carried out by Osmar Moller´s group. These current meter observations are key to understanding the role of the mid-shelf circulation in the large seasonal and shorter time scale variations of the shelf ecosystem revealed by satellite data.
To view Alvaro Cubiella´s report (in Spanish), please follow this link
Undergraduate and graduate students from FURG also participated for training. Two divers examined the bottom conditions before the deployment and the mooring afterwards.
This is the second ADCP mooring installed in the coastal area off Rio Grande. Last year, in October, the same equipment was deployed in an area located further south and successfully recovered by the end of February. Current velocity and direction data were of good quality but the pressure sensor did not work well and the equipment was sent to the manufacturer for service. Because of intense fouling we plan to recover the equipment for service at two month intervals and hope to maintain it at this location for at least one year.
Posted on 31 Oct 2007
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from the field(see all news) 09 Jul 2007 Zeca Muelbert reports from Dichato, Chile The 5th SACC short course is underway at the Estación de Biología Marina, Universidad de Concepción, Concepción (Dichato), Chile. It has been a hands on experience for 26 students from Argentina, Brazil, Colombia, Chile, Mexico, Peru, Uruguay and USA.
News from the field (Zeca Muelbert reports from Dichato, Chile)
The course topic is centered on Physical and Biological Ocean Models. The first part of the course, coupling Hidrodynamic and Biogeochemical Models, is being thought by Dr. Vincent Ecehvin, LOCEAN, Université Pierre et Marie Curie, France. In his part of the course Dr. Ecehvin is combining the Regional Ocean Model System (ROMS) with Nutrient-Phytoplankton-Zooplankton-Detritus models and PISCES.
The second part of the course will start next week. Dr. Carolina Parada, University of Washington, USA, will demonstrate the use of Individual Based (IBM) Models.
from the field(see all news) 21 Jul 2007 Training in color image processing at SHN Silvia Romero trains students in satellite derived ocean color image processing at SHN.
Silvia Romero (center), former SACC Fellow and currently completing her PhD at Universidad de Buenos Aires, trains Magdalena Carranza (left) and Paula Costa Campos (right) in satellite derived ocean color image processing at SHN.
Magdalena is an UBA-AR undergraduate working on environmental indices of Patagonian seas shelf and shelf break fronts.
Paula is a FURG undergraduate visiting SHN as part of her degree, and working on wind induced upwelling events in the vicinity of Cabo Santa Marta Grande, off southern Brazil. Color images provide key information on phytoplankton abundance in these productive ocean environments. The main goal of SACC is to better understand the role of physical forcings in maintaining ocean fronts productive.
general(see all news) 09 Jul 2007 5th SACC International Short Course The 5th SACC International Short Course began on Tuesday 3 July at the Marine Biology Station of the University of Concepción, in Dichato,
The 5th SACC International Short Course began on Tuesday 3 July at the Marine Biology Station of the University of Concepción, in Dichato,
Chile. The course is being financed by CRN2076 and funds from the
COPAS, Proyecto Anillo and IRD.
Twenty six students from Argentina, Brazil, Chile, Colombia, Mexico,
Perú, Uruguay and USA are being trained in aspects of Physical and
Biological Ocean Modeling, which are being taught by Drs. Carolina
Parada Veliz (University of Washington) and Vincent Echevin (University
general(see all news) 24 Oct 2007 Minerva up and running Sun Microsystems cluster Minerva installed at Universidad del Sur
The new nine-processor cluster was acquired using funds from grants from IAI CRN2076, ANPCyT PICT 04-25533 and CONICET PIP6138. The cluster is being used to carry out high-resolution numerical simulations of the ocean circulation in the western South Atlantic. This activity is lead by Elbio Palma (UNS) and Ricardo Matano (OSU).
general(see all news) 24 Oct 2007 Thesis presented at UBA Fernanda Jardon, completed her oceanography undergraduate studies at UBA, where she presented her dissertation entitled "Evidence of fluxes across the Patagonia continental shelf break"
Fernanda used salinity data and space-time variations of satellite derived sea surface temperature near the Patagonia shelf break. She found a salinity minimum region (SMR) in the vicinity of 45-46ºS, which suggests that low salinity waters from the Patagonian shelf are exported offshore. Also at the SMR cross-shelf temperature gradients are weaker than further north and further south. These results are in qualitative agreement with predictions from numerical simulations. This research is relevant to the understanding of cross shore mass, buoyancy and nutrient fluxes around the productive Patagonia shelf break front.
Fernanda has now started to work on her PhD at LOCEAN, University of Paris, we wish her a productive and enjoyable time in Paris!
general(see all news) 24 Jan 2008 How many fronts are there? A study by Barbara Franco and co-authors published this week in Geophysical Research Letters describes a previously undocumented multifrontal structure along the Patagonian shelf break
to see article follow this link:
The study reveals a multiple frontal structure along the Patagonia shelf break. The fronts appear to be linked to multiple branches of the Malvinas Current. The analysis also reveals the frequent development of a band of relatively cold waters inshore of the shelf break, presumably associated with an outer shelf jet.
The shelf break front off Patagonia is associated with a major upwelling system supporting a wide range of marine species. Our study suggests that the multiple fronts may have a significant impact on the ecology of a variety of species. Similar flow structures in other sub-polar western boundary currents may exist.
Barbara is a former SACC Fellow and currently a CONICET doctoral Fellow working in her PhD at Universidad de Buenos Aires. She is currently studying particle drift schemes in numerical simulations for larval drift applications
general(see all news) 14 Mar 2008 Thesis presented at UBA Chlorophyll concentration is an indirect measure of phytoplankton abundance. Its distribution and variability are important because phytoplankton growth absorbs CO2 from the atmosphere. Phytoplankton is also at the base of the oceanic food chain, all marine life depends directly or indirectly on phytoplankton.
Silvia´s work describes the seasonal and interannual chlorophyll variations in surface waters of the western South Atlantic. The work reveals that though there is large chlorophyll variability from seasonal to interannual time scales, chlorophyll blooms frequently occur on the same locations. High-chlorophyll regions are mostly observed close to water mass or vertical stratification transitions, referred to as ocean fronts, which are associated to bottom topography features. As expected, high CO2 absorption from the atmosphere occur at or near these fronts.
Silvia is an Associate Scientist at Servicio de Hidrografía Naval and Teaching Assistant at Universidad de Buenos Aires.
general(see all news) 04 Apr 2008 CO2, winds and phytoplankton Moira Luz Clara defended her undergraduate thesis at UBA
Her work describes the space-time variability of ocean-atmosphere CO2 fluxes determined by different flux parameterizations, and their relation to satellite derived surface chlorophyll variability.
general(see all news) 27 May 2008 Scallops and Ocean Fronts Recent work by Cecilia Mauna (INIDEP, AR) and collaborators describes the tight relationship between Patagonian scallop banks and the variability of frontal regimes of the productive Patagonia shelf break.
The new manuscript entitled "Cross-frontal variations in recruitment and adult abundance of the Patagonian scallop (Zygochlamys patagonica) in the SW Atlantic Shelf Break Front", by Cecilia Mauna and collaborators has been accepted for publication in the ICES Journal of Marine Science. The results are directly related to findings recently reported by Franco et al. (Geophys. Res. Letters, 2008). The Patagonian scallop is a high quality fishery, one of the few globally that has received a seal of endorsement for a sustainable fishery by the Marine Stewardship Council. For more information, contact Cecilia at: firstname.lastname@example.org
general(see all news) 23 Jun 2008 Seminar at UBA Thursday 18 June Jorge Sarmiento (Princeton University) gave a seminar at UBA on the CO2 balance in the atmosphere-land-ocean system.
general(see all news) 29 Jun 2008 Turbid waters A paper by Mariana Framinan, former SACC Fellow and co-authors in press in Jour. Geophysical Res. reports on the fine scale velocity structure near the Rio de la Plata Turbidity front. For info contact email@example.com
Framiñan MB, A Valle-Levinson, HH Sepúlveda and OB Brown, TIDAL VARIATIONS OF FLOW CONVERGENCE, SHEAR AND STRATIFICATION AT THE RIO DE LA PLATA ESTUARY TURBIDITY FRONT
Intratidal variability of density and velocity fields is investigated at the turbidity front of the Río de la Plata Estuary, South America. Current velocity and temperature-salinity profiles collected in August 1999 along a repeated transect crossing the front, are analyzed. Horizontal and vertical gradients, stability of the front, convergence zones, and transverse flow associated to the frontal boundary are described. Strong horizontal convergence of the across-front velocity and build up of along-front velocity shear were observed at the front. In the proximity of the front, enhanced transverse (or along-front) flow created jet-like structures at the surface and near the bottom flowing in opposite directions. These structures persisted throughout the tidal cycle and were advected upstream (downstream) by the flood (ebb) current through a distance of ~10 km. During peak flood, the upper layer flow reversed from its predominant downstream direction and upstream flow occupied the entire water column; outside the peak flood, two-layer estuarine circulation dominated. Changes in density field were observed in response to tidal straining, tidal advection and wind-induced mixing, but stratification remained throughout the tidal cycle. This work demonstrates the large spatial variability of the velocity field at the turbidity front; it provides evidence of enhanced transverse circulation along the frontal boundary; and reveals the importance of advective and frictional intratidal processes in the dynamics of the central part of the estuary.
general(see all news) 29 Jun 2008 New southwest Atlantic model A paper by Elbio Palma and co-authors in press in Jour.Geophysical Res. presents new circulation model results from Tierra del Fuego to Cabo Frio. The authors highlight the significant role of the western boudnary currents on the shelf circulation.
Palma, E.D., R.P. Matano and A.R. Piola, A Numerical Study of the Southwestern Atlantic Shelf Circulation, Journal of Geophysical Research.
This article discusses the results of a suite of numerical simulations of the oceanic circulation in the southwestern Atlantic shelf region that are aimed to characterize its mean circulation, seasonal variability and to determine the dynamical mechanisms controlling them. Our experiments indicate that south of 40°S the mean circulation is dominated by a general northeastward flow in the southern portion of the shelf, which is controlled by the discharges from the Magellan Straits, tidal mixing, wind forcing and the offshore influence of the Malvinas Current farther north. The region from 40°S to 33°S presents the highest seasonal variability, with intrusions of cold subantarctic waters and the northward expansion of mixtures of the Río de la Plata waters in late fall and a slower retraction of the plume during spring-summer. Wind stress variability seems to be the primarily forcing mechanism for the plume dynamics. These model results are in reasonable agreement with observations and previous model results. The present solutions also reveal important additional features of the shelf response. The alongshelf circulation, for example, is largely driven by the western boundary currents in the middle and outer shelf, with induced transports that are three times larger than in experiments forced by winds and tides. The analysis also indicates that the upstream influence of the Malvinas Current is felt well beyond its retroflection point in the form of a northward middle-shelf current and that the interaction of the Brazil Current with the brazilian shelf topography is primarily responsible for inducing steady shelf-break upwelling.
general(see all news) 01 Jul 2008 Plata Special Issue A Special Issue of Continental Shelf Research publishes twelve articles reporting findings of the physical, biological, chemical and geological studies carried out as part of the Plata Project. The Plata project was sponsored by the IAI through CRN061 and CRN2076, the US Office of Naval Research and various Argentine, Brazilian and Uruguayan funding agencies.
PLATA: A synoptic characterization of the southwest Atlantic shelf under influence of the Plata River and Patos Lagoon outflows
Edmo J.D. Campos, Alberto R. Piola, Ricardo P. Matano, Jerry L. Miller
Space-time variability of the Plata plume inferred from ocean color
Alberto R. Piola, Silvia I. Romero, Uriel Zajaczkovski
Variability of chlorophyll-a from ocean color images in the La Plata continental shelf region
Carlos A.E. Garcia, Virginia M.T. Garcia
An overview of physical and ecological processes in the Rio de la Plata Estuary
E. Marcelo Acha, Hermes Mianzan, Raúl Guerrero, José Carreto, Diego Giberto, Norma Montoya, Mario Carignan
Algal pigment patterns and phytoplankton assemblages in different water masses of the Río de la Plata maritime front
José I. Carreto, Nora Montoya, Rut Akselman, Mario O. Carignan, Ricardo I. Silva, Daniel A. Cucchi Colleoni
The effects of river discharge and seasonal winds on the shelf off southeastern South America
Osmar O. Möller Jr., Alberto R. Piola, Ana Cristina Freitas, Edmo J.D. Campos
Patos Lagoon outflow within the Río de la Plata plume using an airborne salinity mapper: Observing an embedded plume
Derek Burrage, Joel Wesson, Carlos Martinez, Tabare Pérez, Osmar Möller Jr., Alberto Piola
Variability of the subtropical shelf front off eastern South America: Winter 2003 and summer 2004
Alberto R. Piola, Osmar O. Möller Jr., Raúl A. Guerrero, Edmo J.D. Campos
Nutrient distributions over the Southwestern South Atlantic continental shelf from Mar del Plata (Argentina) to Itajaí (Brazil): Winter–summer aspects
Elisabete S. Braga, Vitor C. Chiozzini, Gláucia B.B. Berbel, João C.C. Maluf, Valquíria M.C. Aguiar, Marcela Charo, Daniel Molina, Sílvia I. Romero, Beatriz B. Eichler
Biological, physical and chemical properties at the Subtropical Shelf Front Zone in the SW Atlantic Continental Shelf
José H. Muelbert, Marcelo Acha, Hermes Mianzan, Raúl Guerrero, Raúl Reta, Elisabete S. Braga, Virginia M.T. Garcia, Alejandro Berasategui, Mónica Gomez-Erache, Fernando Ramírez
Benthic foraminiferal assemblages of the South Brazil: Relationship to water masses and nutrient distributions
P.P.B. Eichler, B.K. Sen Gupta, B.B. Eichler, E.S. Braga, E.J. Campos
A note on a mineralogical analysis of the sediments associated with the Plata River and Patos Lagoon outflows
Edmo J.D. Campos, Swapna Mulkherjee, Alberto R. Piola, Flavio M.S. de Carvalho
general(see all news) 17 Jul 2008 Submesoscale Turbulence in northern Patagonia A study by X. Capet, E. Campos and A. Paiva, suggests sub-mesoscale turbulence may be ubiquitous in the northern Patagonia continental shelf. Enhanced mixing associated with these scales may have important implications for the marine environment.
Capet, X., E.J.D. Campos and A.M. Pavia, Submesoscale Activity over the Argentinian Shelf, /Geophysical Research Letters/, in press.
Submesoscale activity over the Argentinian shelf is investigated by means of high resolution primitive equation numerical solutions. These reveal energetic turbulent activity (visually similar to the one occasionally seen in satellite images) at scales O(5 km) in fall and winter that is linked to mixed layer baroclinic instability. The air-sea heat flux responsible for (i) deepening the upper ocean boundary layer (at these seasons) and (ii) maintaining a cross shelf background density gradient is the key environmental parameter controlling submesoscale activity. Implications of submesoscale turbulence are investigated. Its mixing efficiency estimated by computing a diffusivity coefficient is above 30 m2 s-1 away from the shallowest regions. Aggregation of surface buoyant material by submesoscale currents occurs within hours and is presumably important to the ecosystem.
general(see all news) 24 Apr 2009 Southwest Atlantic Greenhouse An article by Alejandro Bianchi and co-authors published in Journal of Geophysical Research (Oceans) reports on the annual sea-air CO2 balance based on data from 22 cruises.
Alejandro A. Bianchi, Diana Ruiz Pino, Hernán G. Isbert, Ana P.Osiroff, Valeria Segura, Vivian Lutz, Carlos F. Balestrini and Alberto R. Piola
Sea-air differences of of CO2 partial pressures (ΔpCO2) and fluxes over the Patagonia continental shelf and shelf break are estimated based on near surface observations collected between 2000 and 2006. Chlorophyll a (Chl a) surface distributions and the thermohaline structure across ocean fronts in the shelf are also analyzed based on the above mentioned data set. From spring to autumn, the near shore waters act as a source of CO2, while the rest of the shelf is a CO2 sink, leading to highly negative areal means of sea-air CO2 flux (-4.6mmol•m-2•d-1) and ΔpCO2 (-39 μatm). In winter sea-air ΔpCO2 and CO2 fluxes are close to equilibrium. Sea-air ΔpCO2 and Chl a in the shelf are negatively correlated, suggesting that photosynthesis is one of the main processes acting in the CO2 sequestration. The annual areal mean ΔpCO2 sea-air CO2 flux balance are -3.7mmol•m-2•d-1 and -31μatm respectively. Thus, the Patagonia Sea is one of the strongest CO2 sinks in the World Ocean.
general(see all news) 13 Jun 2009 SACC Human Dimensions Workshop Impacts of changes in the environment on the artisanal fisheries of the Patos Lagoon were discussed during a Workshop held at FURG.
SACC hosted the workshop "Climate change, oceanographic variability and the artisanal fisheries in the SW Atlantic: a human dimension approach". The WS was held in Rio Grande (Brazil) with participants from Argentina, Brazil and Uruguay. The main objective of the WS was to enhance data exchange, understanding and cooperation between natural and social science components of SACC. At the WS, participants shared experiences from similar studies in the region and explore future collaboration.
general(see all news) 10 Jul 2009 Zooplankton and Climate Change - Short Course Scaling the effects of climate change on marine zooplankton a short course being held at USP - Ubatuba
The 9th SACC - CRN2076 Short Course entitled “Scaling the effects of climate change on marine zooplankton” took place from 1 to 10 July 2009 at the Integrated Laboratory on Oceanic Processes, Oceanographic Institute, University of São Paulo, Ubatuba, Brazil. Course instructors were Prof. J. Rudi Strickler from University of Wisconsin Milwaukee and Dr. Rubens Lopes from IOUSP. The course had 30 participants from several IAI ratified member countries including Argentina, Brazil, Chile, Colombia, Peru, and United States, in addition to Poland.
general(see all news) 16 Dec 2009 Recovering historical data Efforts are being conducted to recover historical data stored in obsolete media. Marcela Charo from Servicio de Hidrografía Naval, Argentina, is seen here classifying old 5.25 inch diskettes, where raw ocean profiler (CTD) data were stored in the 1980´s.