Multiscale characterization of spatial relationships among oxycline depth, macrozooplankton, and forage fish off Peru using geostatistics, principal coordinates of neighbour matrices (PCNMs), and wavelets

2012 ◽  
Vol 69 (4) ◽  
pp. 740-754 ◽  
Author(s):  
Daniel Grados ◽  
Ronan Fablet ◽  
Michael Ballón ◽  
Nicolas Bez ◽  
Ramiro Castillo ◽  
...  
Keyword(s):  
Current System ◽  
Marine Ecosystem ◽  
Forage Fish ◽  
Humboldt Current ◽  
Geostatistical Methods ◽  
Physical Forcing ◽  
Principal Coordinates ◽  
Minimum Zone ◽  
Humboldt Current System ◽  
The Impact

Upwelling ecosystems are particularly heterogeneous and present intense mesoscale (tens of kilometres) and submesoscale (hundreds of metres to kilometres) activity that are expected to drive the distribution of the organisms and thus their interactions. Here we addressed the impact of the physical forcing in the northern Humboldt Current system off Peru, which is characterized by the presence of an intense and shallow oxygen minimum zone and used the variability of the depth of the oxycline as a proxy of the physical forcing that impacts the epipelagic communities. We analyzed simultaneous high-resolution acoustic observations of the oxycline depth, the biomass in macrozooplankton, and the biomass in pelagic fish. Three complementary methodologies were considered: (i) geostatistical methods and correlation tests, (ii) principal coordinates of neighbour matrices, and (iii) wavelet analysis. Our results highlight the relevance of a multimethod framework to characterize the multiscale relationships between marine ecosystem components. We also provided evidence that the submesoscale-to-mesoscale variability of the oxycline depth drives the distribution of macrozooplankton, which further structures the distribution of forage fish in a bottom-up cascade.

Climate change scenarios experiments predict a future reduction in small pelagic fish recruitment in the Humboldt Current system

2013 ◽  
Vol 19 (6) ◽  
pp. 1841-1853 ◽  
Author(s):  
Timothée Brochier ◽  
Vincent Echevin ◽  
Jorge Tam ◽  
Alexis Chaigneau ◽  
Katerina Goubanova ◽  
...  
Keyword(s):  
Climate Change ◽  
Current System ◽  
Pelagic Fish ◽  
Climate Change Scenarios ◽  
Small Pelagic Fish ◽  
Humboldt Current ◽  
Fish Recruitment ◽  
Humboldt Current System

scholarly journals Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

2012 ◽  
Vol 9 (3) ◽  
pp. 1183-1194 ◽  
Author(s):  
E. Mayol ◽  
S. Ruiz-Halpern ◽  
C. M. Duarte ◽  
J. C. Castilla ◽  
J. L. Pelegrí
Keyword(s):  
Current System ◽  
Negative Relationship ◽  
Water Layer ◽  
Humboldt Current ◽  
Marine Life ◽  
Small Water ◽  
System A ◽  
Subsurface Waters ◽  
Humboldt Current System ◽  
Upper Mixed Layer

Abstract. Carbon dioxide and coupled CO2 and O2-driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log10 pO2pCO2) and the pH-dependent aragonite saturation (Ω) to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100 m to about 300 m depth and supporting elevated pCO2 values. The lowest RI values, associated to aerobic stress, were found at about 200 m depth and decreased towards the Equator. Increased pCO2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42° S and 28° S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO2–driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO2-driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000 m depth. Overall pCO2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

The Humboldt Current System of Northern and Central Chile

2007 ◽  
pp. 195-344 ◽  
Author(s):  
Martin Thiel ◽  
Erasmo Macaya ◽  
Enzo Acu√±a ◽  
Wolf Arntz ◽  
Horacio Bastias ◽  
...  
Keyword(s):  
Current System ◽  
Humboldt Current ◽  
Central Chile ◽  
Humboldt Current System

scholarly journals Marine heatwaves in the Humboldt current system: from 5-day localized warming to year-long El Niños

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alice Pietri ◽  
François Colas ◽  
Rodrigo Mogollon ◽  
Jorge Tam ◽  
Dimitri Gutierrez
Keyword(s):  
Hot Spot ◽  
Current System ◽  
World Ocean ◽  
Temperature Data ◽  
Sea Surface ◽  
Thermal Impact ◽  
Humboldt Current ◽  
Coastal System ◽  
Long Duration ◽  
Humboldt Current System

AbstractDuring the last 4 decades punctual occurrences of extreme ocean temperatures, known as marine heatwaves (MHWs), have been regularly disrupting the coastal ecosystem of the Peru-Chile eastern boundary upwelling system. In fact, this coastal system and biodiversity hot-spot is regularly impacted by El Niño events, whose variability has been related to the longest and most intense MHWs in the world ocean. However the intensively studied El Niños tend to overshadow the MHWs of shorter duration that are significantly more common in the region. Using sea surface temperature data from 1982 to 2019 we investigate the characteristics and evolution of MHWs, distinguishing events by duration. Results show that long duration MHWs (> 100 days) preferentially affect the coastal domain north of 15° S and have decreased in both occurrence and intensity in the last four decades. On the other hand, shorter events, which represent more than 90% of all the observed MHWs, are more common south of 15° S and show an increase in their thermal impact as well as on the number of affected days, particularly those spanning 30–100 days. We also show that long duration MHWs variability in the coastal domain is well correlated with the remote equatorial variability while the onset of short events (< 10 days) generally goes along with a relaxation of the local coastal wind.

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