The northern Humboldt Current System: Brief history, present status and a view towards the future

Chávez, Francisco P.; Bertrand, Arnaud; Guevara‐Carrasco, Renato; Soler, Pierre; Csirke, Jorge

doi:10.1016/j.pocean.2008.10.012

Cited by 314 publications

(255 citation statements)

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“…This is mainly caused by variability in the intensity of upwellingfavorable winds and the delivery of nutrient-rich Equatorial Subsurface Water (ESSW) that fuels phytoplankton production there (Pennington et al, 2006;Chavez et al, 2008;Chaigneau et al, 2013;Graco et al, 2016). Primary productivity ranges from 1.8 to 5.2 g C m −2 d −1 (Pennington et al, 2006;Quiñones et al, 2010) and leads to a permanent oxygen minimum zone (OMZ) where dissolved oxygen concentrations are essentially zero (Thamdrup et al, 2012;Ulloa et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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: Introductionmentioning

confidence: 99%

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

2017

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“…The average primary productivity in the Humboldt Current LME is moderate, however, the northern Humboldt Current system off Peru produces more fish per unit area than any other region in the world oceans (Chavez et al 2008), representing less than 0.1% of the world ocean surface but presently producing about 10% of the world fish catch. The fishery, as well as the seabirds, depend on a crucial intermediate trophic level of small, plankton-feeding pelagic fish dominated by a few schooling species, especially Peruvian anchoveta (Engraulis ringens Jenyns, 1842) and Pacific sardines (Sardinops sagax (Jenyns, 1842)).…”

Section: Humboldt Current Lmementioning

confidence: 97%

“…Intense wind-induced upwelling cells along the coast result in unusually cool surface waters, relative to latitude. For example, the SST at 58S off Peru is as cool as 168C when most other tropical locations are in excess of 258C (Chavez et al 2008). In addition, the surface oxygenated waters in the Humboldt Current overlie an intense and extremely shallow Oxygen Minimum Zone that forms a barrier and concentrates living resources near the surface, thus making them available for seabirds.…”

Section: Humboldt Current Lmementioning

confidence: 99%

“…1950Á1970; 1985 to the present). During a warmer period from 1970 to 1985 (termed 'El Viejo'), sardines became dominant as anchovy populations were restricted to smaller coastal upwelling cells for feeding and spawning, increasing egg and larval cannibalism and predation, and anchovy catchability (Alheit & Niquen 2004;Chavez et al 2008). The example shows how small pelagic fish such as sardine and anchovy respond dramatically and quickly to changes in ocean climate, causing dramatic changes in abundance over a few decades.…”

Section: Humboldt Current Lmementioning

confidence: 99%

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Impacts of climate variation and potential effects of climate change on South American seabirds – a review

Quillfeldt

Masello

2013

Marine Biology Research

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The coastal and oceanic waters around the South American coasts provide rich foraging grounds for breeding and wintering seabirds, but there is growing concern that climate change will provide additional pressures to the seabirds around South America. As in many other coastal ecosystems, seabirds around South America are already faced with threats to their breeding habitats such as human disturbance and introduced predators, and threats at sea such as persistent pollutants and pesticides and direct mortality risks due to fisheries and oil spills. The sensitivity of South American marine ecosystems to ocean climate anomalies is well known from the dramatic population collapses caused by El Niñ o Southern Oscillation (ENSO) events. However, longer-term climate change effects have been explored less often and few long-term data sets exist for South American seabirds. Seven Large Marine Ecosystems (LME) border South America. While all LMEs experienced warming during the last 50 years, their climate dynamics have differed in recent decades. Climate models suggest that potential climate change effects may be important, especially due to changes in ENSO intensity and frequency and associated changes in the ocean climate of Atlantic and Pacific marine ecosystems. In this review, we found that the best studied seabird communities are those of the Patagonian Shelf and the Humboldt Current, but overall, our knowledge on climate effects on South American seabirds is scarce.

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“…For example, the Costa Rica Dome (Fig. 2) is an oceanic upwelling center where the thermocline is shallow (Sasai et al, 2007), whereas the waters off Peru (PE) are primarily affected by the cold northward flowing Humboldt Current and are associated with strong upwelling of cool subsurface waters (Chavez et al, 2008).…”

Section: Sexual Size Dimorphismmentioning

confidence: 99%

Geographic variations of jumbo squid (Dosidicus gigas) based on gladius morphology

Gong¹,

Chen²,

Li³

et al. 2017

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Abstract-The jumbo flying squid (Dosidicus gigas) is widely distributed in the eastern Pacific Ocean and its population structure is complex. Morphometric analysis of hard structures of cephalopods is frequently employed to explore the geographic variation within discreet population units. In this study, 8 morphometric characteristics of the gladius, or pen, were measured and compared from 562 jumbo squid specimens collected off Peru, the Costa Rica Dome, and from the equatorial central eastern Pacific. The growth rate of the gladius was evaluated by comparing it with the ages determined from statoliths. Results showed significant differences in gladii morphology between sexes and geographic populations. Stepwise discriminant analysis indicated that gladius morphometric characteristics were suitable discriminatory variables with an overall correct classification rate of 78.6% for distinguishing different populations. Higher daily growth rates were found in the proostracum than in the conus, possibly because of the different biological functions of these anatomical parts. These results support our general hypothesis that gladius morphology provides an alternative way to distinguish potential geographic populations of D. gigas and it adds new information regarding the gladius of the Ommastrephidae.Morphometric analysis has been an accepted method for studying the geographic variation of population units within species of cephalopods (Nesis, 1993; Crespi-Abril et al., 2010;Liu et al., 2015a; van der Vyver et al., 2016). Cephalopods show high phenotypic plasticity in both soft and hard structures owing to their biological characteristics, such as rapid growth, short life span, and highly migratory activity (Crespi-Abril et al., 2010;Arkhipkin et al., 2015; van der Vyver et al., 2016). Therefore, morphometric analysis may be a useful approach for studying geographic variations in pelagic cephalopods that have an extensive distribution range.The jumbo flying squid (Dosidicus gigas) is widely distributed in the eastern Pacific Ocean, extending from Alaska (60°N) to Chile (46°S) and stretching to the west (125°-140°W) at the Equator (Nigmatullin et al., 2001; Ibáñez and Cubillos, 2007). As a pelagic cephalopod, D. gigas has an important ecological function in marine ecosystems, not only as a voracious predator but also as a valuable source of prey (Field et al., 2007; Alegre et al., 2014). It also supports an important commercial fishery, and in 2014 the annual catch exceeded 1,000,000 metric tons (FAO, 2016). The main fishing regions are located off the coasts of Chile and Peru, off the Costa Rica Dome and within the Gulf of California.Throughout its geographic range, the population structure of D. gigas is complicated and often debated. In the past, three distinguishable groups with a different size-at-ma- It has been assumed that there is a small group that occurs in the near-equatorial waters, a medium-size group that is distributed within the entire distribution range, and a large-size group that occurs at th...

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The northern Humboldt Current System: Brief history, present status and a view towards the future

Cited by 314 publications

References 64 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)

Impacts of climate variation and potential effects of climate change on South American seabirds – a review

Geographic variations of jumbo squid (Dosidicus gigas) based on gladius morphology

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