Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration... more Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration is extremely low. They are suspected to be expanding in response to global warming. However, currently, the mechanisms by which OMZ varies in response to climate variability are still uncertain. Here, the variability of the subtropical OMZ off central Chile of a regional coupled physical–biogeochemical regional model simulation was analyzed for the period 2000–2008, noting that its fluctuations were significant despite the relatively weak amplitude of the El Niño/Southern Oscillation (ENSO). In particular, the interannual variability in the OMZ volume (OMZVOL, defined as the volume with dissolved oxygen concentration (DO) ≤ 45μM) was approximately 38% larger than that of the seasonal cycle, with maximum and minimum anomalies of OMZVOL taking place during two cold La Niña (LN) years (2001 and 2007). The model analyses further reveal that these anomalies resulted from a combined effect of...
IntroductionOn-going climate change is now recognized to yield physiological stresses on marine s... more IntroductionOn-going climate change is now recognized to yield physiological stresses on marine species, with potentially detrimental effects on ecosystems. Here, we evaluate the prospect of using climate velocities (CV) of the metabolic index (Φ) for assessing changes in habitat in the South East Pacific.MethodsOur approach is based on a species with mean ecophysiotype (i.e. model species) and the use of a global Earth System Model simulation (CESM-LE) under RCP 8.5 scenario. The SEP is chosen as a case study as it hosts an Oxygen Minimum Zone and seamounts systems sustaining local communities through artisanal fisheries.Results and DiscussionOur results indicate that CVΦ pattern is mainly constrained by the oxygen distribution and that its sign is affected by contrasting oxygen trends (including a re-oxygenation in the upper OMZ) and warming. We further show that CVΦ is weakly dependent on physiological traits composing Φ, which conveys to this metrics some value for inferring the...
The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to globa... more The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to global ocean productivity and provide critical ecosystem services to human society. The impact of climate change on EBUSs and the ecosystems they support is thus a subject of considerable interest. Here, we review hypotheses of climate-driven change in the physics, biogeochemistry, and ecology of EBUSs; describe observed changes over recent decades; and present projected changes over the twenty-first century. Similarities in historical and projected change among EBUSs include a trend toward upwelling intensification in poleward regions, mitigatedwarming in near-coastal regions where upwelling intensifies, and enhanced water-column stratification and a shoaling mixed layer. However, there remains significant uncertainty in how EBUSs will evolve with climate change, particularly in how the sometimes competing changes in upwelling intensity, source-water chemistry, and stratification will affect...
In this paper, we outline the need for a coordinated international effort toward the building of ... more In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO2DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO2DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO2DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO2DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O2 changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data syn...
La distribucion y variabilidad de la Zona Minimo de Oxigeno (ZMO) localizada frente a Chile centr... more La distribucion y variabilidad de la Zona Minimo de Oxigeno (ZMO) localizada frente a Chile central esta fuertemente asociada a la variabilidad del Agua Ecuatorial Subsuperficial y a la surgencia costera desarrollada frente a Chile. A su vez, estos procesos estan relacionado con el transporte hacia el sur de la Corriente Subsuperficial Peru-Chile (CSPC) que fluye a lo largo del talud y plataforma continental de Chile. El objetivo de este estudio es documentar la variabilidad estacional del oxigeno disuelto (OD) entre 0-45 μ M frente a la costa central de Chile y analizar su relacion con la CSPC. Para este fin, se utiliza una simulacion numerica fisica-biogeoquimica de alta resolucion (1/12°) que acopla el modelo hidrodinamico ROMS con el modelo biogeoquimico BioEBUS. La validacion del modelo con observaciones in-situ y una base de datos climatologica (CARS-2009), indican una buena representacion de los principales aspectos de la variabilidad espacio-temporal de la region de estudio....
While observations suggest a long-term expansion of the Oxygen Minimum Zone (OMZ) in the South Ea... more While observations suggest a long-term expansion of the Oxygen Minimum Zone (OMZ) in the South Eastern Pacific (SEP), it also exhibits a large interannual to decadal variability in its upper and lower limits. The uncertainty of the fate of the SEP OMZ in a warmer climate as simulated by Earth system models also questions to which extent natural variability in the OMZ can obscure the detection of externally forced trends. Here we analyze long-term simulations from a hierarchy of models of the OMZ off Peru and Chile and show that a significant share of the variability is not linearly related to climate modes (including ENSO), suggesting that it originates from internal dynamics associated to both local non-linear physical and biogeochemical processes. Still the OMZ volume tends to shrink during strong Eastern Pacific El Nino while it expands during La Nina and Central Pacific El Nino events. It is shown in particular that La Nina and strong El Nino events significantly modulate the OM...
The processes maintaining the Oxygen Minimum Zone (OMZ) of the Eastern Tropical Pacific are still... more The processes maintaining the Oxygen Minimum Zone (OMZ) of the Eastern Tropical Pacific are still uncertain. This region is embedded into the so-called shadow zone of the eastern Pacific so that the weak thermocline ventilation is the background mechanism that explains to some extent its mean spatial structure. However biogeochemical processes take place in regions where the environment is highly variable leading to characteristic vertical scales of variability of the minimum O2 concentration that do not necessarily reflects the ocean dynamics. This can be the case for instance near the coast in the vicinity of the thermocline which is connected to the remote equatorial variability (Kelvin wave) or/and locally wind forced. Here we document the vertical structure variability of the OMZ from regional biogeochemical coupled model simulations. We use the linear formalism of the ocean dynamics to define metrics of the O2 vertical structure variability in order to compare the different ti...
1 Laboratoire d’Etudes en Géophysique et Océanographie SpatialesLEGOS, UMR5566-CNRS /IRD/UT/CNES,... more 1 Laboratoire d’Etudes en Géophysique et Océanographie SpatialesLEGOS, UMR5566-CNRS /IRD/UT/CNES, Toulouse, France 2 Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile 3 Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile 4 Millennium Nucleus for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Coquimbo, Chile 5 Instituto Geofísico del Perú, Lima, Perú
Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, b... more Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. These changes have accelerated consumption of oxygen by microbial respiration, reduced solubility of oxygen in water, and reduced the rate of oxygen resupply from the atmosphere to the ocean interior, with a wide range of biological and ecological consequences. Further research is needed to understand and predict long-term, global- and regional-scale oxygen changes and their effects on marine and estuarine fisheries and ecosystems.
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…
Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration... more Oxygen minimum zones (OMZs) are extended oceanic regions for which dissolved oxygen concentration is extremely low. They are suspected to be expanding in response to global warming. However, currently, the mechanisms by which OMZ varies in response to climate variability are still uncertain. Here, the variability of the subtropical OMZ off central Chile of a regional coupled physical–biogeochemical regional model simulation was analyzed for the period 2000–2008, noting that its fluctuations were significant despite the relatively weak amplitude of the El Niño/Southern Oscillation (ENSO). In particular, the interannual variability in the OMZ volume (OMZVOL, defined as the volume with dissolved oxygen concentration (DO) ≤ 45μM) was approximately 38% larger than that of the seasonal cycle, with maximum and minimum anomalies of OMZVOL taking place during two cold La Niña (LN) years (2001 and 2007). The model analyses further reveal that these anomalies resulted from a combined effect of...
IntroductionOn-going climate change is now recognized to yield physiological stresses on marine s... more IntroductionOn-going climate change is now recognized to yield physiological stresses on marine species, with potentially detrimental effects on ecosystems. Here, we evaluate the prospect of using climate velocities (CV) of the metabolic index (Φ) for assessing changes in habitat in the South East Pacific.MethodsOur approach is based on a species with mean ecophysiotype (i.e. model species) and the use of a global Earth System Model simulation (CESM-LE) under RCP 8.5 scenario. The SEP is chosen as a case study as it hosts an Oxygen Minimum Zone and seamounts systems sustaining local communities through artisanal fisheries.Results and DiscussionOur results indicate that CVΦ pattern is mainly constrained by the oxygen distribution and that its sign is affected by contrasting oxygen trends (including a re-oxygenation in the upper OMZ) and warming. We further show that CVΦ is weakly dependent on physiological traits composing Φ, which conveys to this metrics some value for inferring the...
The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to globa... more The world's eastern boundary upwelling systems (EBUSs) contribute disproportionately to global ocean productivity and provide critical ecosystem services to human society. The impact of climate change on EBUSs and the ecosystems they support is thus a subject of considerable interest. Here, we review hypotheses of climate-driven change in the physics, biogeochemistry, and ecology of EBUSs; describe observed changes over recent decades; and present projected changes over the twenty-first century. Similarities in historical and projected change among EBUSs include a trend toward upwelling intensification in poleward regions, mitigatedwarming in near-coastal regions where upwelling intensifies, and enhanced water-column stratification and a shoaling mixed layer. However, there remains significant uncertainty in how EBUSs will evolve with climate change, particularly in how the sometimes competing changes in upwelling intensity, source-water chemistry, and stratification will affect...
In this paper, we outline the need for a coordinated international effort toward the building of ... more In this paper, we outline the need for a coordinated international effort toward the building of an open-access Global Ocean Oxygen Database and ATlas (GO2DAT) complying with the FAIR principles (Findable, Accessible, Interoperable, and Reusable). GO2DAT will combine data from the coastal and open ocean, as measured by the chemical Winkler titration method or by sensors (e.g., optodes, electrodes) from Eulerian and Lagrangian platforms (e.g., ships, moorings, profiling floats, gliders, ships of opportunities, marine mammals, cabled observatories). GO2DAT will further adopt a community-agreed, fully documented metadata format and a consistent quality control (QC) procedure and quality flagging (QF) system. GO2DAT will serve to support the development of advanced data analysis and biogeochemical models for improving our mapping, understanding and forecasting capabilities for ocean O2 changes and deoxygenation trends. It will offer the opportunity to develop quality-controlled data syn...
La distribucion y variabilidad de la Zona Minimo de Oxigeno (ZMO) localizada frente a Chile centr... more La distribucion y variabilidad de la Zona Minimo de Oxigeno (ZMO) localizada frente a Chile central esta fuertemente asociada a la variabilidad del Agua Ecuatorial Subsuperficial y a la surgencia costera desarrollada frente a Chile. A su vez, estos procesos estan relacionado con el transporte hacia el sur de la Corriente Subsuperficial Peru-Chile (CSPC) que fluye a lo largo del talud y plataforma continental de Chile. El objetivo de este estudio es documentar la variabilidad estacional del oxigeno disuelto (OD) entre 0-45 μ M frente a la costa central de Chile y analizar su relacion con la CSPC. Para este fin, se utiliza una simulacion numerica fisica-biogeoquimica de alta resolucion (1/12°) que acopla el modelo hidrodinamico ROMS con el modelo biogeoquimico BioEBUS. La validacion del modelo con observaciones in-situ y una base de datos climatologica (CARS-2009), indican una buena representacion de los principales aspectos de la variabilidad espacio-temporal de la region de estudio....
While observations suggest a long-term expansion of the Oxygen Minimum Zone (OMZ) in the South Ea... more While observations suggest a long-term expansion of the Oxygen Minimum Zone (OMZ) in the South Eastern Pacific (SEP), it also exhibits a large interannual to decadal variability in its upper and lower limits. The uncertainty of the fate of the SEP OMZ in a warmer climate as simulated by Earth system models also questions to which extent natural variability in the OMZ can obscure the detection of externally forced trends. Here we analyze long-term simulations from a hierarchy of models of the OMZ off Peru and Chile and show that a significant share of the variability is not linearly related to climate modes (including ENSO), suggesting that it originates from internal dynamics associated to both local non-linear physical and biogeochemical processes. Still the OMZ volume tends to shrink during strong Eastern Pacific El Nino while it expands during La Nina and Central Pacific El Nino events. It is shown in particular that La Nina and strong El Nino events significantly modulate the OM...
The processes maintaining the Oxygen Minimum Zone (OMZ) of the Eastern Tropical Pacific are still... more The processes maintaining the Oxygen Minimum Zone (OMZ) of the Eastern Tropical Pacific are still uncertain. This region is embedded into the so-called shadow zone of the eastern Pacific so that the weak thermocline ventilation is the background mechanism that explains to some extent its mean spatial structure. However biogeochemical processes take place in regions where the environment is highly variable leading to characteristic vertical scales of variability of the minimum O2 concentration that do not necessarily reflects the ocean dynamics. This can be the case for instance near the coast in the vicinity of the thermocline which is connected to the remote equatorial variability (Kelvin wave) or/and locally wind forced. Here we document the vertical structure variability of the OMZ from regional biogeochemical coupled model simulations. We use the linear formalism of the ocean dynamics to define metrics of the O2 vertical structure variability in order to compare the different ti...
1 Laboratoire d’Etudes en Géophysique et Océanographie SpatialesLEGOS, UMR5566-CNRS /IRD/UT/CNES,... more 1 Laboratoire d’Etudes en Géophysique et Océanographie SpatialesLEGOS, UMR5566-CNRS /IRD/UT/CNES, Toulouse, France 2 Centro de Estudios Avanzados en Zonas Áridas, La Serena, Chile 3 Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile 4 Millennium Nucleus for Ecology and Sustainable Management of Oceanic Islands (ESMOI), Coquimbo, Chile 5 Instituto Geofísico del Perú, Lima, Perú
Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, b... more Oxygen is fundamental to life. Not only is it essential for the survival of individual animals, but it regulates global cycles of major nutrients and carbon. The oxygen content of the open ocean and coastal waters has been declining for at least the past half-century, largely because of human activities that have increased global temperatures and nutrients discharged to coastal waters. These changes have accelerated consumption of oxygen by microbial respiration, reduced solubility of oxygen in water, and reduced the rate of oxygen resupply from the atmosphere to the ocean interior, with a wide range of biological and ecological consequences. Further research is needed to understand and predict long-term, global- and regional-scale oxygen changes and their effects on marine and estuarine fisheries and ecosystems.
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…
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