ENSO diversity driving low-frequency change in mesoscale activity off Peru and Chile

Conejero, Carlos; Dewitte, Boris; Garçon, Véronique; Sudre, Joël; Montès, Ivonne

doi:10.1038/s41598-020-74762-x

Cited by 13 publications

(16 citation statements)

References 77 publications

(130 reference statements)

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“…Long-term changes in the frequency or intensity of basin-scale ocean-atmosphere phenomena, or in the strength of their teleconnections to EBUSs, represent another remote-forcing mechanism through which climate change can influence EBUS properties. Under present-day conditions, the remote processes associated with ENSO, the Benguela Niño, or other modes of natural variability (Bonino et al 2019) can affect the winds ( Jacox et al 2015), mean circulation (Montes et al 2011), eddy activity (Conejero et al 2020), water-mass composition (Bograd et al 2019), and biogeochemical properties of EBUSs (Garçon et al 2019). Changes in these patterns of variability can also impact EBUS source waters, their properties, or the riverine input to coastal waters (Dunn et al 2018).…”

Section: Vertical Structure and Source Watersmentioning

confidence: 99%

Climate Change Impacts on Eastern Boundary Upwelling Systems

Bograd

Jacox

Hazen

et al. 2023

Annu. Rev. Mar. Sci.

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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 productivity and ecosystem structure. We summarize the commonalities and differences in historical and projected change in EBUSs and conclude with an assessment of key remaining uncertainties and questions. Future studies will need to address these questions to better understand, project, and adapt to climate-driven changes in EBUSs.

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Section: Vertical Structure and Source Watersmentioning

confidence: 99%

Climate Change Impacts on Eastern Boundary Upwelling Systems

Bograd

Jacox

Hazen

et al. 2023

Annu. Rev. Mar. Sci.

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“…The next section addresses the relative importance of the main drivers of frontogenesis in the region. A clear distinction between those physical processes would require carrying dynamical diagnostics such as eddy kinetic budgets [e.g., Conejero et al (2020)], eddy kinetic energy decompositions [e.g., Martínez-Moreno et al (2019; or frontogenesis function decompositions [e.g., Koseki et al (2019)] based on the model outputs, which would fall beyond the scope of this work. We nonetheless argue that thermal fronts in the MC depends on mean and seasonal circulation, seasonal upwellings and variations of EKE.…”

Section: Main Drivers Of Frontogenesis In the MCmentioning

confidence: 99%

Spatial and seasonal variability of horizontal temperature fronts in the Mozambique Channel for both epipelagic and mesopelagic realms

Sudre

Dewitte²,

Mazoyer³

et al. 2023

Front. Mar. Sci.

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IntroductionOcean fronts are moving ephemeral biological hotspots forming at the interface of cooler and warmer waters. In the open ocean, this is where marine organisms, ranging from plankton to mesopelagic fish up to megafauna, gather and where most fishing activities concentrate. Fronts are critical ecosystems so that understanding their spatio-temporal variability is essential not only for conservation goals but also to ensure sustainable fisheries. The Mozambique Channel (MC) is an ideal laboratory to study ocean front variability due to its energetic flow at sub-to-mesoscales, its high biodiversity and the currently debated conservation initiatives. Meanwhile, fronts detection relying solely on remotely-sensed Sea Surface Temperature (SST) cannot access aspects of the subsurface frontal activity that may be relevant for understanding ecosystem dynamics.MethodIn this study, we used the Belkin and O’Reilly Algorithm on remotely-sensed SST and hindcasts of a high-resolution nested ocean model to investigate the spatial and seasonal variability of temperature fronts at different depths in the MC.ResultsWe find that the seasonally varying spatial patterns of frontal activity can be interpreted as resulting from main features of the mean circulation in the MC region. In particular, horizontally, temperature fronts are intense and frequent along continental shelves, in islands’ wakes, at the edge of eddies, and in the pathways of both North-East Madagascar Current (NEMC) and South-East Madagascar Current (SEMC). In austral summer, thermal fronts in the MC are mainly associated with the Angoche upwelling and seasonal variability of the Mozambique current. In austral winter, thermal fronts in the MC are more intense when the NEMC and the Seychelles-Chagos and South Madagascar upwelling cells intensify. Vertically, the intensity of temperature fronts peaks in the vicinity of the mean thermocline.DiscussionConsidering the marked seasonality of frontal activity evidenced here and the dynamical connections of the MC circulation with equatorial variability, our study calls for addressing longer timescales of variability to investigate how ocean ecosystem/front interactions will evolve with climate change.

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“…of the SPCZ to a more zonal alignment closer to the equator (Cai et al, 2012;Vincent et al, 2011) (Combes et al, 2015;Conejero et al, 2020), which in turn can influence SST and oceanographic conditions in the vicinity of the islands as eddies propagate westwards from the coastal region.…”

Section: Mean Oceanic Surface Circulation In the Sepmentioning

confidence: 99%

Understanding the impact of climate change on the oceanic circulation in the Chilean island ecoregions

Dewitte

Conejero

Ramos

et al. 2021

Aquatic Conservation

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1. The largest changes in the circulation of the Southeastern Pacific resulting from global warming are associated with the southward shift and intensification of the anticyclone and with coastal surface warming. Coastal upwelling is projected to be increase off central Chile, due to an increase in equatorward winds, although increased oceanic stratification and associated enhanced nearshore turbulence will yield an onshore deepening/flattening of the thermocline. 2. The overall increase in south-easterly trade winds of the Southeastern Pacific in a warmer climate are likely to increase the connectivity pattern between Juan Fernandez and Desventuradas islands, and along the Sala y Gomez ridge, through increasing wind-driven mean ocean currents. 3. Deoxygenation associated with the warmer temperatures and changes in ventilation are likely to modify marine habitat and the respiratory barriers of species in the seamounts located in the vicinity of the limits of the minimum oxygen zone. 4. In the Southeastern Pacific, the prevailing 2D understanding of the responses of marine life to climate change needs to be expanded to 3D approaches, integrating the vertical habitat compression of marine organisms as a result of ocean warming and deoxygenation, as climate velocities for temperature and oxygen have contrasting vertical and horizontal patterns. 5. There is a need for regional biogeochemical-coupled modelling studies dedicated to the Chilean islands in order to provide an integrated view of the impact of anthropogenic stressors (e.g. deoxygenation, increased stratification, and climate shift) at the scale required for addressing socio-ecological interactions. 6. A refined understanding of the large-scale biogeography and spatial dynamics of marine populations through experimentation with high-resolution regional ocean models is a prerequisite for scaling-up regional management planning and optimizing the conservation of interconnected marine ecosystems across large scales.

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ENSO diversity driving low-frequency change in mesoscale activity off Peru and Chile

Cited by 13 publications

References 77 publications

Climate Change Impacts on Eastern Boundary Upwelling Systems

Climate Change Impacts on Eastern Boundary Upwelling Systems

Spatial and seasonal variability of horizontal temperature fronts in the Mozambique Channel for both epipelagic and mesopelagic realms

Understanding the impact of climate change on the oceanic circulation in the Chilean island ecoregions

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