The seasonal cycle of surface chlorophyll in the Peruvian upwelling system: A modelling study

Échevin, Vincent; Aumont, Olivier; Ledesma, Jesús; Flores, Georgina

doi:10.1016/j.pocean.2008.10.026

Cited by 156 publications

(167 citation statements)

References 29 publications

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“…The intra-annual biogeochemistry of the Peruvian upwelling system is well-recognized, resulting from strong seasonality in the intensity of upwelling, primary production and hydrodynamic factors (Pennington et al, 2006;Echevin et al, 2008Echevin et al, , 2014Gutiérrez et al, 2008;Graco et al, 2016). Yet, the corresponding variability in sediment biogeochemistry on the Peruvian shelf is only just beginning to be appreciated.…”

Section: Discussion Sediment Feedbacks On the Peruvian Shelfmentioning

confidence: 99%

“…This discrepancy can be traced back to the variability in the chlorophyll concentrations rather than SST. SeaWiFS mean monthly chlorophyll concentrations in the Peruvian coastal zone have been shown to underestimate the measured in situ concentrations by as much as 100% (Echevin et al, 2008). This implies that MODIS derived satellite data may be more accurate than SeaWiFS for this geographical region.…”

Section: Poc Rain Rate (Rrpoc)mentioning

confidence: 98%

“…Monthly vertical profiles of temperature, salinity, oxygen and nutrients (nitrate, nitrite, phosphate and silicate) have been measured there by the Instituto del Mar del Perú (IMARPE) between 1996 and 2009 (Graco et al, 2016). The station is located in a main upwelling cell that experiences maximum primary production in the austral summer (February-April, low upwelling), hereafter termed "summer, " and lower productivity in austral winter (JulySeptember, high upwelling), hereafter termed "winter" (Echevin et al, 2008). An example of satellite derived chlorophyll a in the wider region during one of our research campaigns (January 2013) clearly shows the elevated values along the coastal margin where upwelling strength is greatest ( Figure 1B).…”

Section: Site Descriptionmentioning

confidence: 99%

“…An example of satellite derived chlorophyll a in the wider region during one of our research campaigns (January 2013) clearly shows the elevated values along the coastal margin where upwelling strength is greatest ( Figure 1B). Highest rates of primary productivity are 6 months out of phase with upwelling intensity due to several factors including light limitation as a result of the deepening of the mixed layer during the upwelling period (Echevin et al, 2008;Quiñones et al, 2010). Data from the time-series station show that the vertical extent of the OMZ exhibits significant variability at different time scales due to El Niño and the passage of coastal trapped waves (Graco et al, 2016).…”

Section: Site Descriptionmentioning

confidence: 99%

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Strong and Dynamic Benthic-Pelagic Coupling and Feedbacks in a Coastal Upwelling System (Peruvian Shelf)

2017

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Monthly time-series data (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)) of bottom water oxygen, nitrate and nitrite concentrations from the outer shelf (150 m water depth) in the oxygen minimum zone offshore Peru were coupled to a layered biogeochemical sediment model to investigate benthic-pelagic coupling over multi-annual time scales. The model includes the mineralization of four reactive pools of particulate organic carbon (POC) with lifetimes of 0.13, 1.3, 20, and 1700 year that were constrained using empirical data. Total POC rain rates to the seafloor were derived from satellite based estimates of primary production. Solute fluxes and concentrations in sediment porewater showed highly dynamic behavior over the course of a typical year. Conversion of fixed N to N 2 by denitrification varied from 1.1 mmol m −2 d −1 of N in winter to 1.8 mmol m −2 d −1 of N in summer with a long term mean N loss for the shelf of 1.5 mmol m −2 d −1 of N. Fixed N loss across the whole time-series agreed very well with a previously-published vertically-integrated sediment model for coupling the benthic and pelagic N cycle in regional and global models. Dissimilatory nitrate reduction to ammonium (DNRA) emerges as a major process in the benthic N cycle, producing on average 1.9 mmol m −2 d −1 of ammonium: more than twice the rate of ammonification of organic nitrogen. The model predicts sulfide emissions from the sediment of up to 1 mmol m −2 d −1 when POC rain rate exceeds 20 mmol m −2 d −1 , in agreement with past observations of benthic sulfide fluxes and sulfide plume distributions in the water column. This study demonstrates that sediments on the Peruvian shelf are not static repositories that are independent of changes taking place in the water column. Our results strongly suggest the shelf sediments must exert an important feedback on biogeochemical processes in the overlying waters, and should be considered in regional model studies.

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Section: Discussion Sediment Feedbacks On the Peruvian Shelfmentioning

confidence: 99%

Section: Poc Rain Rate (Rrpoc)mentioning

confidence: 98%

Section: Site Descriptionmentioning

confidence: 99%

Section: Site Descriptionmentioning

confidence: 99%

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Strong and Dynamic Benthic-Pelagic Coupling and Feedbacks in a Coastal Upwelling System (Peruvian Shelf)

2017

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“…The trench lies below the Humboldt Current and the Peruvian upwelling system (Echevin et al 2008), a region of high surface productivity (averaging 269 g C m -2 year -1 , Longhurst et al 1995) with values reported as high as 3,613 g C m -2 year -1 (Fossing et al 1995).…”

Section: Study Sitementioning

confidence: 99%

Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability

et al. 2011

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Holothuroidea represent the dominant benthic megafauna in hadal trenches (*6,000-11,000 m), but little is known about their behaviour and functional role at such depths. Using a time-lapse camera at 8,074 m in the PeruChile Trench (SE Pacific Ocean), we provide the first in situ observations of locomotory activity for the elasipodid holothurian Elpidia atakama Belyaev in Shirshov Inst Oceanol 92: 326-367, (1971). Time-lapse sequences reveal 'run and mill' behaviour whereby bouts of feeding activity are interspersed by periods of locomotion. Over the total observation period (20 h 25 min), we observed a mean (±SD) locomotion speed of 7.0 ± 5.7 BL h -1 , but this increased to 10.9 ± 7.2 BL h -1 during active relocation and reduced to 4.8 ± 2.9 BL h -1 during feeding. These observations show E. atakama translocates and processes sediment at rates comparable to shallower species despite extreme hydrostatic pressure and remoteness from surfacederived food.

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Peru‐Chile upwelling dynamics under climate change

et al. 2015

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The consequences of global warming on the Peru-Chile Current System (PCCS) ocean circulation are examined with a high-resolution, eddy-resolving regional oceanic model. We performed a dynamical downscaling of climate scenarios from the IPSL-CM4 Coupled General Circulation Model (CGCM), corresponding to various levels of CO 2 concentrations in the atmosphere. High-resolution atmospheric forcing for the regional ocean model are obtained from the IPSL atmospheric model run on a stretched grid with increased horizontal resolution in the PCCS region. When comparing future scenarios to preindustrial (PI) conditions, the circulation along the Peru and Chile coasts is strongly modified by changes in surface winds and increased stratification caused by the regional warming. While the coastal poleward undercurrent is intensified, the surface equatorial coastal jet shoals and the nearshore mesoscale activity are reinforced. Reduction in alongshore wind stress and nearshore wind stress curl drive a year-round reduction in upwelling intensity off Peru. Modifications in geostrophic circulation mitigate this upwelling decrease in late austral summer. The depth of the upwelling source waters becomes shallower in warmer conditions, which may have a major impact on the system's biological productivity.

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The seasonal cycle of surface chlorophyll in the Peruvian upwelling system: A modelling study

Cited by 156 publications

References 29 publications

Strong and Dynamic Benthic-Pelagic Coupling and Feedbacks in a Coastal Upwelling System (Peruvian Shelf)

Strong and Dynamic Benthic-Pelagic Coupling and Feedbacks in a Coastal Upwelling System (Peruvian Shelf)

Functional effects of the hadal sea cucumber Elpidia atakama (Echinodermata: Holothuroidea, Elasipodida) reflect small-scale patterns of resource availability

Peru‐Chile upwelling dynamics under climate change

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