Offshore transport of particulate organic carbon in the California Current System by mesoscale eddies

Amos, Caitlin M.; Castelao, Renato M.; Medeiros, Patricia M.

doi:10.1038/s41467-019-12783-5

Cited by 35 publications

(52 citation statements)

References 56 publications

(103 reference statements)

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“…A high particulate organic carbon offshore transport of ca. 1050 km by mesoscale eddies is observed in other EBUEs such as the California Current (Amos et al, 2019). The estimated advective fluxes from ESTOC also fall in the range of values from the Cape Blanc area (Fischer et al, , 2016(Fischer et al, , 2019, where winter was the most prominent season for lateral advection of particles.…”

Section: Lateral Particle Advection From the Cape Ghir Filament And Cmentioning

confidence: 53%

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

et al. 2020

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Eastern Boundary Upwelling Ecosystems (EBUEs) are associated with high biological productivity, high fish catch and they highly contribute to marine carbon sequestration. Whether coastal upwelling has intensified or weakened under climate change in the past decades is controversially discussed and different approaches (e.g., timeseries of chlorophyll, wind, sea surface temperature, modeling experiments) have been considered. We present a record of almost two decades of particle fluxes (1991-2009) from ca. 600 to 3100 m water depth in the Canary Basin at site ESTOC (European Station for Time series in the Ocean Canary Islands; ca. 29 • N, 15 • 30.W, ca. 3600 m water depth), located in the offshore transition zone of the northern Canary Current-EBUE. We compare these flux records with those measured at a mesotrophic sediment trap site further south off Cape Blanc (Mauritania, ca. 21 • N). The deep ocean fluxes at ESTOC in ca. 3 km recorded the evolution of the coastal Cape Ghir filament (30-32 • N, 10-12 • W) due to lateral advection of particles, whereas the upper water column sediment traps in ca. 1 km reflected the oligotrophic conditions in the overlying waters of ESTOC. We observed an increased emphasis in springtime fluxes since 2005, associated with a change in particle composition, while satellite chlorophyll biomass did not show this pattern. Due to its northern location in the CC-EBUEs, spring biogenic fluxes at ESTOC provide a better relationship to the forcing of the North Atlantic Oscillation than those recorded further south off Cape Blanc. Off Cape Blanc, deep fluxes showed the best overlap with the deep ESTOC fluxes during the spring season before 2005. On the long-term, both chlorophyll and particle fluxes showed an increasing trend at ESTOC which was not observed further south at the mesotrophic Cape Blanc site. This might indicate that, depending on their location along the NW African margin, coastal upwelling systems react differently to global change.

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Section: Lateral Particle Advection From the Cape Ghir Filament And Cmentioning

confidence: 53%

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

et al. 2020

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“…Recent studies (Amos et al., 2019; Lovecchio et al., 2017) estimate organic carbon offshore transport in EBUS through lateral advection. Amos et al.…”

Section: Discussionmentioning

confidence: 99%

Cross‐Shore Flow and Implications for Carbon Export in the California Current Ecosystem: A Lagrangian Analysis

et al. 2021

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In Eastern boundary upwelling systems (EBUS), winds blow alongshore during the upwelling season, causing nutrient-replete deep waters to come to the euphotic zone through divergence of Ekman transport at the coast, stimulating elevated net primary production (NPP) and inorganic carbon uptake. This primary production induces secondary production, the recycling of nutrients, and export of organic carbon into the aphotic zone. EBUSs are strongly advective systems: Ekman currents, as well as intense geostrophic mesoscale eddies and filaments, transport nearshore surface water offshore. The transport of organic matter (OM) from formation sites to export sites, occurs in three-dimensional space: the location of carbon export may be offset spatially from the region of elevated PP (

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“…The low near‐surface salinity in the eddies thus restratifies the upper layer (increases the vertical gradient of density) and shoals the MLD (Figure 8a). Eddies are also suggested able to trap parcels of water during formation and advect the trapped water properties away with the migration of the eddies (Amos et al, 2019; Lehahn et al, 2011). In the eastern Bay of Bengal where most eddies originate, the ILDs (MLDs) in the anticyclonic eddies are already deeper (shallower) than the background levels (Figures 9b and 9g), suggesting that these changes are more likely to be dominated by eddy convergence and downwelling rather than by eddy trapping.…”

Section: Discussionmentioning

confidence: 99%

“…These eddies occupy 25–30% of the global ocean surface (Chaigneau et al, 2009) and contain approximately 90% of the total kinetic energy of the oceans (Ferrari & Wunsch, 2009). They transport properties such as heat, salt, and carbon around the seas (Amos et al, 2019; Chelton, Gaube, et al, 2011; Dong et al, 2014), playing essential roles in oceanic material transport and energy cycle. Recent observations have shown that eddies can alter the vertical structure of the ocean, such as the mixed layer (Gaube et al, 2019; Hausmann et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Anticyclonic Eddies Enhance the Winter Barrier Layer and Surface Cooling in the Bay of Bengal

Zhan

Cai

2020

JGR Oceans

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Oceanic barrier layer impedes the vertical exchanges of heat and biogeochemical substances between the mixed layer and deep ocean, playing essential roles in modulating air-sea heat flux and oceanic biogeochemical cycles. Recent studies revealed that mesoscale eddies can modify the vertical motions of the mixed layer. But their influence on the barrier layer has not been determined. By analyzing more than a decade of in situ, satellite, and reanalysis data, this study investigated the influence of eddies on barrier layer in the Bay of Bengal. The results show that the barrier layer in anticyclonic eddies is significantly thickened in winter (by 50% on average). This thickening consists of the deepening of isothermal layer by eddy downwelling and the shoaling of mixed layer by near-surface salinity restratification. The thickening of the barrier layer enlarges with latitude, in consistent with the reinforcement in salinity stratification and surface cooling. The thickened barrier layer impedes the upward supply of heat into the mixed layer from the below, promoting the winter surface cooling (by 0.7°C on average) and subsurface temperature inversion (by 0.6°C on average). The feature is contrary to the intuitive expectation that anticyclonic eddies possess high sea surface temperature in eddy interiors. As a consequence, both cyclonic and anticyclonic eddies result in negative sea surface temperature anomalies, indicative of a net decrease in the local sea surface temperature. These effects of eddies may be a common feature in salinity-stratified oceans in winter and have potential implications for the local biogeochemistry and air-sea coupled models. Plain Language Summary Oceanic barrier layer impedes the vertical exchanges of heat and biogeochemical substances between the near-surface and deep ocean, playing essential roles in modulating sea surface temperature, air-sea heat flux, and oceanic biogeochemical cycles. Here, we investigated the influence of mesoscale eddies on the barrier layer in the Bay of Bengal. We show that in such salinity-stratified oceans, anticyclonic eddies significantly thicken the barrier layer in winter. This thickening consists of the deepening of isothermal layer and the shoaling of mixed layer. The thickened barrier layer impedes the upward supply of heat into the mixed layer and retains the heat in the barrier layer, promoting the winter surface cooling and subsurface temperature inversion. As a consequence, sea surface temperature is lower in the eddies compared to the ambient, contrasting to the intuitive expectation that anticyclonic eddies possess high temperature. In addition to the low sea surface temperature in cyclonic eddies, both types of the eddies lead to surface cooling, breaking the standard symmetry of cyclonic versus anticyclonic eddies, whose effects usually cancel each other out. These results may potentially have far-reaching implications from the local biogeochemistry to climate models which, due to their coarse, non-eddy-resolving resolution, are unable to capt...

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Offshore transport of particulate organic carbon in the California Current System by mesoscale eddies

Cited by 35 publications

References 56 publications

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

Long-Term Changes of Particle Flux in the Canary Basin Between 1991 and 2009 and Comparison to Sediment Trap Records Off Mauritania

Cross‐Shore Flow and Implications for Carbon Export in the California Current Ecosystem: A Lagrangian Analysis

Anticyclonic Eddies Enhance the Winter Barrier Layer and Surface Cooling in the Bay of Bengal

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