Regime shifts in the Humboldt Current ecosystem

Alheit, Jürgen; Ñiquen, Miguel

doi:10.1016/j.pocean.2004.02.006

Cited by 285 publications

(188 citation statements)

References 29 publications

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“…The Peru upwelling system presents the higher fishery production exactly because of the presence of both Sardinela aurita and Engraulis ringens species (MOLONEY et al, 2005). The alternation of dominance between these fishes restructures the ecosystem from phytoplankton to top predators (ALHEIT;NIQUEN, 2004). Anchovy shares the carbon fixed by phytoplankton with copepods but predatory fishery on Engraulis ringens increases carbon fluxes from copepods to euphasiids and sardines, as well as detritus flocculation to the benthic system (CURY et al, 2000).…”

Section: Nekton Trophodynamics and Fishery Productionmentioning

confidence: 99%

Biophysical interactions in the Cabo Frio upwelling system, southeastern Brazil

et al. 2012

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A B S T R A C TThe rising of cold water from deeper levels characterizes coastal upwelling systems. This flow makes nutrients available in the euphotic layer, which enhances phytoplankton production and growth. On the Brazilian coast, upwelling is most intense in the Cabo Frio region (RJ). The basic knowledge of this system was reviewed in accordance with concepts of biophysical interactions. The high frequency and amplitude of the prevailing winds are the main factor promoting the rise of South Atlantic Central Water, but meanders and eddies in the Brazil Current as well as local topography and coast line are also important. Upwelling events are common during spring/summer seasons. Primary biomass is exported by virtue of the water circulation and is also controlled by rapid zooplankton predation. Small pelagic fish regulate plankton growth and in their turn are preyed on by predatory fish. Sardine furnishes an important regional fish stock. Shoreline irregularities define the embayment formation of the Marine Extractive Reserve of Arraial do Cabo making it an area with evident different intensities of upwelled water that harbors high species diversity. Consequently, on a small spatial scale there are environments with tropical and subtropical features, a point to be explored as a particularity of this ecosystem. R E S U M OOs sistemas costeiros de ressurgência são caracterizados pela ascensão de águas frias que tornam os nutrientes disponíveis na camada eufótica para o crescimento e aumento da produção fitoplanctônica. No Brasil, a região do Cabo Frio (RJ) é o principal sistema de ressurgência costeira. O objetivo desse artigo foi revisar o atual conhecimento desse sistema através dos conceitos sobre interações biofísicas. A ascensão da Água Central do Atlântico Sul ocorre devido à alta frequência e amplitude dos ventos, à presença de meandros e vórtices na Corrente do Brasil, além da topografia local e da linha de costa. Os eventos de ressurgência são comuns durante os períodos de primavera/verão e a biomassa primária é exportada devido à circulação da água, sendo também controlada pela rápida predação zooplanctônica. Os pequenos peixes pelágicos regulam o crescimento do plâncton e são consumidos pelos peixes predadores, resultando em um importante estoque pesqueiro regional. A irregularidade da costa define as enseadas do Cabo Frio, na Reserva Extrativista Marinha do Arraial do Cabo, apresentando distintas influências das águas ressurgidas e resultando em grande diversidade de espécies. Consequentemente, ambientes com características tropicais e subtropicais são observados dentro de uma pequena escala espacial, o que constitui uma particularidade desse ecossistema.

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Section: Nekton Trophodynamics and Fishery Productionmentioning

confidence: 99%

Biophysical interactions in the Cabo Frio upwelling system, southeastern Brazil

et al. 2012

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“…Small pelagic fish catch dynamics in Sechura are mainly due to latitudinal migrations of the stocks in response to changing centers of upwelling and associated plankton variability. One example is the southward retreat of the Peruvian anchoveta during the strong EN of 1997/98 (Alheit and Ñ iquen 2004), which helps in explaining the decreased catches in Sechura. Cephalopod catches have increased following the EN of 1997/98 to become an important target of the artisanal fishery.…”

Section: Applicability Of Trophic Modeling To the Sechura Bay Ecosystemmentioning

confidence: 99%

Trophic and environmental drivers of the Sechura Bay Ecosystem (Peru) over an ENSO cycle

et al. 2007

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Interannual environmental variability in Peru is dominated by the El Niño Southern Oscillation (ENSO). The most dramatic changes are associated with the warm El Niño (EN) phase (opposite the cold La Niña phase), which disrupts the normal coastal upwelling and affects the dynamics of many coastal marine and terrestrial resources. This study presents a trophic model for Sechura Bay, located at the northern extension of the Peruvian upwelling system, where ENSO-induced environmental variability is most extreme. Using an initial steady-state model for the year 1996, we explore the dynamics of the ecosystem through the year 2003 (including the strong EN of 1997/98 and the weaker EN of 2002/03). Based on support from literature, we force biomass of several non-trophicallymediated 'drivers' (e.g. Scallops, Benthic detritivores, Octopus, and Littoral fish) to observe whether the fit between historical and simulated changes (by the trophic model) is improved. The results indicate that the Sechura Bay Ecosystem is a relatively inefficient system from a community energetics point of view, likely due to the periodic perturbations of ENSO. A combination of high system productivity and low trophic level target species of invertebrates (i.e. scallops) and fish (i.e. anchoveta) results in high catches and an efficient fishery. The importance of environmental drivers is suggested, given the relatively small improvements in the fit of the simulation with the addition of trophic drivers on remaining functional groups' dynamics. An additional multivariate regression model is presented for the scallop Argopecten purpuratus, which demonstrates a significant correlation between both spawning stock size and riverine discharge-mediated mortality on catch levels. These results are discussed in the context of the appropriateness of trophodynamic modeling in relatively open systems, and how management strategies may be focused given the highly environmentally influenced marine resources of the region.

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“…The waters oV Central Peru are productive regions that support economically important Wsheries (Carrasco and Lozano 1989;Chavez et al 2003;Alheit and Niquen 2004). Another characteristic of this region is a well-developed oxygen minimum layer (Wyrtki 1967;Judkins 1980;Mackas et al 1981), which occurs nearly continuously in most of the Humboldt Current System (Zuta and Guillen 1970;Heinrich 1973;Calienes and Guillen 1981;Pizarro et al 2002).…”

Section: Introductionmentioning

confidence: 99%

Zooplankton vertical distribution and migration off Central Peru in relation to the oxygen minimum layer

et al. 2007

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Vertical distribution and diel vertical migration of a zooplankton community were studied at two stations oV Central Peru in April 2006. Zooplankton was collected at Wve depth strata by vertical hauls with Hydo-Bios multinet (300-m mesh, 0.25-m 2 mouth size). The zooplankton community was distributed in relation to a strong, shallow oxycline (1 ml l ¡1 oxygen isopleth generally above 36 m). The highest total abundance was always in the upper, welloxygenated layer. The most important species were: Acartia tonsa (72.86%), Centropages brachiatus (7.5%), and Paracalanus parvus (3.1%); Acartia tonsa was the dominant species at all times. Larvae of the polychaete Magelona sp. (7.5%) and larvae of the brachiopod Discinisca lamellosa (3.5%) were numerically dominant in April and small copepods e.g. Oncaea venusta (3.88%) were numerically dominant during August. Five distinct patterns of vertical distribution and migration in relation to the oxygen minimum layer were distinguished in this study: (1) Ontogenetic vertical migration through the oxycline (Acartia tonsa adults, nauplii, and copepodids), (2) permanent limitation to layers above the oxycline (e.g. Oikopleura sp., most invertebrate larvae), (3) distribution mostly below the oxycline with occasional migration into the layers just above the oxycline (Eucalanus inermis), (4) Diel Vertical Migration (Centropages brachiatus), and (5) reverse Diel Vertical Migration (larvae of the polychaete Magelona sp.).

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Regime shifts in the Humboldt Current ecosystem

Cited by 285 publications

References 29 publications

Biophysical interactions in the Cabo Frio upwelling system, southeastern Brazil

Biophysical interactions in the Cabo Frio upwelling system, southeastern Brazil

Trophic and environmental drivers of the Sechura Bay Ecosystem (Peru) over an ENSO cycle

Zooplankton vertical distribution and migration off Central Peru in relation to the oxygen minimum layer

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