Evolution and biological effects of the 1997–98 El Niño in the upwelling ecosystem off northern Chile

Ulloa, Osvaldo; Escribano, Rubén; Hormazábal, Samuel; Quiñones, Renato A.; González, Rodrigo R.; Ramos, Marcel

doi:10.1029/2000gl011548

Cited by 139 publications

(105 citation statements)

References 14 publications

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“…Although McPhaden (1999) suggested the 1997-1998 EN as the strongest on record, according to some physical indices, the biological impact oV northern Chile was not as catastrophic as generally expected. This does not only hold true for the analysed soft-bottom community, but also for the pelagic ecosystem of the same area (Ulloa et al 2001). DiVerences in the impact compared with previous events may be attributed to the distinct seasonal onset (Arntz 2002): while EN 1982-1983 …”

Section: Feeding Modesmentioning

confidence: 86%

“…El Niño as a community modulating factor According to Ulloa et al (2001) who analysed time-series data of a coastal location oV Antofagasta (23°03ЈS, 70°27ЈW), a Wrst marked deepening of the thermocline and oxycline occurred at the end of April 1997, indicating the arrival of perturbations associated with the start of 1997-1998 EN in the region. Indeed, the 10 m sample taken during winter 1997 does not match the group of the remaining (Soenens 1985).…”

Section: Feeding Modesmentioning

confidence: 99%

“…Oxygen limitation (Levin et al 1991) explains the low diversity during non-EN years at deeper bottoms (Palma et al 2005). When physiological tolerance limits are no longer exceeded due to improved oxygen concentrations in the bottom water (Tarazona et al 1988b;Gutiérrez et al 2000;Ulloa et al 2001) previously excluded species may extend their distribution to lower and greater depths ("immigrants" sensu Tarazona et al 1988a) or proliferate strongly ("opportunists"). Additionally subordinate and carnivorous species may be allowed to re-emerge (Valdivia et al 2005).…”

Section: Feeding Modesmentioning

confidence: 99%

“…This oceanographic pattern can be aVected by the large-scale El Niño Southern Oscillation (ENSO) (e.g. Taraba 1959;Brandhorst 1971;Navea and Miranda 1980;Fonseca 1989;Arntz and Fahrbach 1991;Fuenzalida 1992a, b;Morales et al 1996;Gonzalez and Marín 1998;Strub et al 1998;Escribano 1998;Ulloa et al 2001;Arntz et al 2006). Monitoring the sea surface temperature oV Chile and Peru has illustrated that ENSO shows an interannual climate oscillation between warm phases (El Niño: EN) and enhanced cold phases (La Niña: LN).…”

Section: Introductionmentioning

confidence: 99%

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Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

et al. 2007

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The macrozoobenthos of Mejillones Bay (23°S; Humboldt Current) was quantitatively investigated over a 7-year period from austral summer 1995/1996 to winter 2002. About 78 van Veen grab samples taken at six stations (5, 10, 20 m depth) provided the basis for the analysis of the distribution of 60 species and 28 families of benthic invertebrates, as well as of their abundance and biomass. Mean abundance (2,119 individuals m ¡2 ) was in the same order compared to a previous investigation; mean biomass (966 g formalin wet mass m ¡2 ), however, exceeded prior estimations mainly due to the dominance of the bivalve Aulacomya ater. About 43% of the taxa inhabited the complete depth range. Mean taxonomic Shannon diversity (HЈ, Log e) was 1.54 § 0.58 with a maximum at 20 m (1.95 § 0.33); evenness increased with depth. The fauna was numerically dominated by carnivorous gastropods, polychaetes and crustaceans (48%). About 15% of the species were suspensivorous, 13% sedimentivorous, 11% detritivorous, 7% omnivorous and 6% herbivorous. Cluster analyses showed a signiWcant diVerence between the shallow and the deeper stations. Gammarid amphipods and the polychaete family Nephtyidae characterized the 5-mzone, the molluscs Aulacomya ater, Mitrella unifasciata and gammarids the intermediate zone, while the gastropod Nassarius gayi and the polychaete family Nereidae were most prominent at the deeper stations. The communities of the three depth zones did not appear to be limited by hypoxia during non-El Niño conditions. Therefore, no typical change in community structure occurred during El Niño 1997-1998, in contrast to what was observed for deeper faunal assemblages and hypoxic bays elsewhere in the coastal Humboldt Current system.

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Section: Feeding Modesmentioning

confidence: 86%

Section: Feeding Modesmentioning

confidence: 99%

Section: Feeding Modesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

et al. 2007

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“…These increments in net N 2 O production in the OMZ core can generate a major efflux of N 2 O into the atmosphere. Such situations could occur during El Niño events, when oxygenation in the upper water column off northern Chile can double (Ulloa et al 2001). These events produce strong physical and biological changes in the OMZ off northern Chile, affecting O 2 levels, NO 3 -and organic carbon supply, and gas fluxes in the water column (González et al 1998, Ulloa et al 2001).…”

Section: O 2 Regulation Of N 2 O Cycling Off Northern Chilementioning

confidence: 99%

N2O cycling at the core of the oxygen minimum zone off northern Chile

Castro-González¹,

Farı́as²

2004

Mar. Ecol. Prog. Ser.

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Vertical modeling of the nitrogen cycle in the eastern tropical South Pacific oxygen deficient zone using high‐resolution concentration and isotope measurements

Peters

Babbin

Lettmann

et al. 2016

Global Biogeochemical Cycles

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Marine oxygen deficient zones (ODZs) have long been identified as sites of fixed nitrogen (N) loss. However, the mechanisms and rates of N loss have been debated, and traditional methods for measuring these rates are labor‐intensive and may miss hot spots in spatially and temporally variable environments. Here we estimate rates of heterotrophic nitrate reduction, heterotrophic nitrite reduction (denitrification), nitrite oxidation, and anaerobic ammonium oxidation (anammox) at a coastal site in the eastern tropical South Pacific (ETSP) ODZ based on high‐resolution concentration and natural abundance stable isotope measurements of nitrate (NO3−) and nitrite (NO2−). These measurements were used to estimate process rates using a two‐step inverse modeling approach. The modeled rates were sensitive to assumed isotope effects for NO3− reduction and NO2− oxidation. Nevertheless, we addressed two questions surrounding the fates of NO2− in the ODZ: (1) Is NO2− being primarily reduced to N2 or oxidized to NO3− in the ODZ? and (2) what are the contributions of anammox and denitrification to NO2− removal? Depth‐integrated rates from the model suggest that 72–88% of the NO2− produced in the ODZ was oxidized back to NO3−, while 12–28% of NO2− was reduced to N2. Furthermore, our model suggested that 36–74% of NO2− loss was due to anammox, with the remainder due to denitrification. These model results generally agreed with previously measured rates, though with a large range of uncertainty, and they provide a long‐term integrated view that compliments incubation experiments to obtain a broader picture of N cycling in ODZs.

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Evolution and biological effects of the 1997–98 El Niño in the upwelling ecosystem off northern Chile

Cited by 139 publications

References 14 publications

Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

Sublittoral soft bottom communities and diversity of Mejillones Bay in northern Chile (Humboldt Current upwelling system)

N2O cycling at the core of the oxygen minimum zone off northern Chile

Vertical modeling of the nitrogen cycle in the eastern tropical South Pacific oxygen deficient zone using high‐resolution concentration and isotope measurements

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