In addition to being one of the most productive upwelling systems, the oceanic region off Peru is... more In addition to being one of the most productive upwelling systems, the oceanic region off Peru is embedded in one of the most extensive Oxygen Minimum Zones (OMZs) of the world ocean. The dynamics of the OMZ off Peru remain uncertain, partly due to the scarcity of data and to the ubiquitous role of mesoscale activity on the circulation and biogeochemistry. Here we use a high-resolution coupled physical/biogeochemical model simulation to investigate the seasonal variability of the OMZ off Peru. The focus is on characterizing the seasonal cycle in Dissolved…
An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) req... more An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air–sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO<sub>2</sub> (…
The Southern Ocean is thought to be a sink of atmospheric CO2 although the uptake magnitude is st... more The Southern Ocean is thought to be a sink of atmospheric CO2 although the uptake magnitude is still a matter of debate. We report the first estimates of ocean-atmosphere CO2 fluxes from the Weddell Sea west of 30°W based on observations collected in the austral summers between 2001 and 2005. . The data consists of high-resolution sea surface temperature, salinity, carbonate system (pCO2, TCO2, Alkalinity), dissolved O2 and nutrients (nitrates, phosphates and silicates), phytoplankton taxonomy and biomass (total Chl-a for three size class, < 0.5μm, >10μm and 5μm< Chl-a
ABSTRACT We study the variability of the Eastern Tropical Pacific Oxygen Minimum Zone (OMZ) devel... more ABSTRACT We study the variability of the Eastern Tropical Pacific Oxygen Minimum Zone (OMZ) developed off Peru, using Lagrangian tools based on the dynamical systems theory. We focus on the identification of dynamical mechanisms, pathways and barriers to transport water masses with high/low oxygen content inside and outside the OMZ, using the concept of Lagrangian coherent structures (LCS) and residence times. The finite-size Lyapunov exponent (FSLE) is used to identify the relevant LCSs within the OMZ area. Our preliminary results show that the core of the OMZ is characterized by weak circulation while the boundaries of the OMZ have shorter residence times with a complex spatial distribution, consisting of filaments with low and high residence time. Incursions of low residence time into the OMZ core also present a filament shape. In addition, the middepth mean FSLE and dissolved O2 fields indicate a clear correlation between the northern and southern OMZ boundaries and high mean FSLE zones. These zones, so-called &#39;corridors&#39;, are thought to signal the pathways of mesoscale eddies from where they were originated - the coastal upwelling areas. The instantaneous FSLE field is organized into thin regions of high values within a low FSLE background field. These high FSLE regions are related to the boundaries of mesoscale and submesoscale eddies and fronts occupying the Eastern Tropical Pacific, released in the near shore upwelling zones. On the boundaries of the OMZ, these high FSLE lines are seen to separate waters with dissimilar dissolved oxygen content. Eddies of extreme low dissolved oxygen concentrations that penetrate the OMZ tend to remain coherent and do not mix with the surrounding waters; this is due to the existence of LCSs that form barriers around the eddies. This mechanism could contribute to the maintenance of the OMZ off Peru.
To elucidate the different oceanographic and biogeochemical conditions controlling N2O cycling an... more To elucidate the different oceanographic and biogeochemical conditions controlling N2O cycling and its exchange across the air–sea interface, N2O, O2, nutrients, and other hydrographic variables were measured monthly at a fixed station located on the continental shelf at ∼36°S. Sampling lasted one year and included upwelling (53% of the time, principally in austral summer) and non-upwelling periods (47% of the
Environmental context Understanding the exchange of energy, gases and particles at the ocean–atmo... more Environmental context Understanding the exchange of energy, gases and particles at the ocean–atmosphere interface is critical for the development of robust predictions of, and response to, future climate change. The international Surface Ocean–Lower Atmosphere Study (SOLAS) coordinates multi-disciplinary ocean–atmosphere research projects that quantify and characterise this exchange. This article details five new SOLAS research strategies – upwellings and associated oxygen minimum zones, sea ice, marine aerosols, atmospheric nutrient supply and ship emissions – that aim to improve knowledge in these critical areas. This review focuses on critical issues in ocean–atmosphere exchange that will be addressed by new research strategies developed by the international Surface Ocean–Lower Atmosphere Study (SOLAS) research community. Eastern boundary upwelling systems are important sites for CO2 and trace gas emission to the atmosphere, and the proposed research will examine how heterotrophi...
The oxygen minimum zones (OMZs) are recognized as intense sources of N2O greenhouse gas (GHG) and... more The oxygen minimum zones (OMZs) are recognized as intense sources of N2O greenhouse gas (GHG) and could also be potential sources of CO2, the most important GHG for the present climate change. This study evaluates, for one of the most intense and shallow ...
In addition to being one of the most productive upwelling systems, the oceanic region off Peru is... more In addition to being one of the most productive upwelling systems, the oceanic region off Peru is embedded in one of the most extensive Oxygen Minimum Zones (OMZs) of the world ocean. The dynamics of the OMZ off Peru remain uncertain, partly due to the scarcity of data and to the ubiquitous role of mesoscale activity on the circulation and biogeochemistry. Here we use a high-resolution coupled physical/biogeochemical model simulation to investigate the seasonal variability of the OMZ off Peru. The focus is on characterizing the seasonal cycle in Dissolved…
An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) req... more An accurate quantification of the role of the ocean as source/sink of greenhouse gases (GHGs) requires to access the high-resolution of the GHG air–sea flux at the interface. In this paper we present a novel method to reconstruct maps of surface ocean partial pressure of CO<sub>2</sub> (…
The Southern Ocean is thought to be a sink of atmospheric CO2 although the uptake magnitude is st... more The Southern Ocean is thought to be a sink of atmospheric CO2 although the uptake magnitude is still a matter of debate. We report the first estimates of ocean-atmosphere CO2 fluxes from the Weddell Sea west of 30°W based on observations collected in the austral summers between 2001 and 2005. . The data consists of high-resolution sea surface temperature, salinity, carbonate system (pCO2, TCO2, Alkalinity), dissolved O2 and nutrients (nitrates, phosphates and silicates), phytoplankton taxonomy and biomass (total Chl-a for three size class, < 0.5μm, >10μm and 5μm< Chl-a
ABSTRACT We study the variability of the Eastern Tropical Pacific Oxygen Minimum Zone (OMZ) devel... more ABSTRACT We study the variability of the Eastern Tropical Pacific Oxygen Minimum Zone (OMZ) developed off Peru, using Lagrangian tools based on the dynamical systems theory. We focus on the identification of dynamical mechanisms, pathways and barriers to transport water masses with high/low oxygen content inside and outside the OMZ, using the concept of Lagrangian coherent structures (LCS) and residence times. The finite-size Lyapunov exponent (FSLE) is used to identify the relevant LCSs within the OMZ area. Our preliminary results show that the core of the OMZ is characterized by weak circulation while the boundaries of the OMZ have shorter residence times with a complex spatial distribution, consisting of filaments with low and high residence time. Incursions of low residence time into the OMZ core also present a filament shape. In addition, the middepth mean FSLE and dissolved O2 fields indicate a clear correlation between the northern and southern OMZ boundaries and high mean FSLE zones. These zones, so-called &#39;corridors&#39;, are thought to signal the pathways of mesoscale eddies from where they were originated - the coastal upwelling areas. The instantaneous FSLE field is organized into thin regions of high values within a low FSLE background field. These high FSLE regions are related to the boundaries of mesoscale and submesoscale eddies and fronts occupying the Eastern Tropical Pacific, released in the near shore upwelling zones. On the boundaries of the OMZ, these high FSLE lines are seen to separate waters with dissimilar dissolved oxygen content. Eddies of extreme low dissolved oxygen concentrations that penetrate the OMZ tend to remain coherent and do not mix with the surrounding waters; this is due to the existence of LCSs that form barriers around the eddies. This mechanism could contribute to the maintenance of the OMZ off Peru.
To elucidate the different oceanographic and biogeochemical conditions controlling N2O cycling an... more To elucidate the different oceanographic and biogeochemical conditions controlling N2O cycling and its exchange across the air–sea interface, N2O, O2, nutrients, and other hydrographic variables were measured monthly at a fixed station located on the continental shelf at ∼36°S. Sampling lasted one year and included upwelling (53% of the time, principally in austral summer) and non-upwelling periods (47% of the
Environmental context Understanding the exchange of energy, gases and particles at the ocean–atmo... more Environmental context Understanding the exchange of energy, gases and particles at the ocean–atmosphere interface is critical for the development of robust predictions of, and response to, future climate change. The international Surface Ocean–Lower Atmosphere Study (SOLAS) coordinates multi-disciplinary ocean–atmosphere research projects that quantify and characterise this exchange. This article details five new SOLAS research strategies – upwellings and associated oxygen minimum zones, sea ice, marine aerosols, atmospheric nutrient supply and ship emissions – that aim to improve knowledge in these critical areas. This review focuses on critical issues in ocean–atmosphere exchange that will be addressed by new research strategies developed by the international Surface Ocean–Lower Atmosphere Study (SOLAS) research community. Eastern boundary upwelling systems are important sites for CO2 and trace gas emission to the atmosphere, and the proposed research will examine how heterotrophi...
The oxygen minimum zones (OMZs) are recognized as intense sources of N2O greenhouse gas (GHG) and... more The oxygen minimum zones (OMZs) are recognized as intense sources of N2O greenhouse gas (GHG) and could also be potential sources of CO2, the most important GHG for the present climate change. This study evaluates, for one of the most intense and shallow ...
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Papers by A. Paulmier