Changes in biological productivity and ocean-climatic fluctuations during the last ~ 1.5 kyr in the Humboldt ecosystem off northern Chile (27°S): A multiproxy approach

Castillo, Alexis; Valdés, Jorge; Sifeddine, A.; Reyss, Jean-Louis; Bouloubassi, Ioanna; Ortlieb, Luc

doi:10.1016/j.palaeo.2017.07.038

Cited by 19 publications

(22 citation statements)

References 110 publications

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“…At lower latitudes, a slight increase in oxygen near the OMZ core is noticeable for the last half century that seems decoupled from increased export production (Fig. 3.3.3c) (Gutiérrez et al, 2009;Salvatteci et al, 2014;Castillo et al, 2017). Further south, at 36 • S, a decrease in the concentration of redox sensitive metals in the continental shelf sediments from ~1930 to ~2005 (Srain et al, 2015), suggests a regional-level signature to the oxygenation trend (Castillo et al, 2017).…”

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 95%

“…3.3.3c) (Gutiérrez et al, 2009;Salvatteci et al, 2014;Castillo et al, 2017). Further south, at 36 • S, a decrease in the concentration of redox sensitive metals in the continental shelf sediments from ~1930 to ~2005 (Srain et al, 2015), suggests a regional-level signature to the oxygenation trend (Castillo et al, 2017).…”

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 95%

“…A bi-decadal period around the 1870s (characterized by strong ENSO activity; Gutiérrez et al, 2011) featured diatom-rich sedimentation events from Central Peru to Northern Chile. These events were associated with strong water column deoxygenation and bottom anoxia as inferred from δ 15 N records in sedimentary organic matter and enrichment of redox-sensitive metals (Gutiérrez et al, 2009;Díaz-Ochoa et al, 2011;Salvatteci et al, 2014;Castillo et al, 2017).…”

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 97%

“…Proxies for water column denitrification, including sediment redox conditions, bioturbation and benthic foraminifera, among others, have been used to reconstruct past variation of subsurface oxygenation in the region (Higginson and Altabet, 2004;Morales et al, 2006;Gutiérrez et al, 2009;Salvatteci et al, 2014Salvatteci et al, , 2016Erdem and Schönfeld, 2017;Díaz-Ochoa et al, 2011;Castillo et al, 2017). At multidecadal to millennial timescales, the intensity and extension of the OMZ is modulated by changes in the Walker circulation, which controls the thermocline depth and thereby the productivity and respiration in the ETSP, as well as the subsurface ventilation associated with the equatorial currents (Agnihotri et al, 2008;Gutiérrez et al, 2009;Xu et al, 2015;Salvatteci et al, 2016).…”

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 99%

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System controls of coastal and open ocean oxygen depletion

Pitcher

Aguirre-Velarde

Breitburg

et al. 2021

Progress in Oceanography

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The epoch of the Anthropocene, a period during which human activity has been the dominant influence on climate and the environment, has witnessed a decline in oxygen concentrations and an expansion of oxygendepleted environments in both coastal and open ocean systems since the middle of the 20th century. This paper provides a review of system-specific drivers of low oxygen in a range of case studies representing marine systems in the open ocean, on continental shelves, in enclosed seas and in the coastal environment. Identification of similar and contrasting responses within and across system types and corresponding oxygen regimes is shown to be informative both in understanding and isolating key controlling processes and provides a sound basis for predicting change under anticipated future conditions. Case studies were selected to achieve a balance in system diversity and global coverage. Each case study describes system attributes, including the present-day oxygen environment and known trends in oxygen concentrations over time. Central to each case study is the identification of the physical and biogeochemical processes that determine oxygen concentrations through the tradeoff between ventilation and respiration. Spatial distributions of oxygen and time series of oxygen data provide the opportunity to identify trends in oxygen availability and have allowed various drivers of low oxygen to be distinguished through correlative and causative relationships. Deoxygenation results from a complex interplay of hydrographic and biogeochemical processes and the superposition of these processes, some additive and others subtractive, makes attribution to any particular driver challenging. System-specific models are therefore required to achieve a quantitative understanding of these processes and of the feedbacks between processes at varying scales.

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Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 95%

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 95%

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 97%

Section: Paleo-oxygenation and Recent Trendsmentioning

confidence: 99%

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System controls of coastal and open ocean oxygen depletion

Pitcher

Aguirre-Velarde

Breitburg

et al. 2021

Progress in Oceanography

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“…Most paleoceanographic reconstructions for the SEP from the late Quaternary are based on sediment cores collected from the continental margin. During the last decades, these records were generally compared with open ocean data, because data from nearer to the coast was lacking (e.g., Castillo et al., 2017; De Pol‐Holz et al., 2006, 2007; Haddam et al., 2018, 2020; Siani et al., 2013). Our new compilation of δ 13 C DIC data combined with temperature, salinity, oxygen, and nutrient data (Figures 2 and 4) reveal significant differences in the distribution of water masses in the upper ∼1,000 m of the water column between the oceanic and the coastal sections.…”

Section: Resultsmentioning

confidence: 99%

Isotopic Characterization of Water Masses in the Southeast Pacific Region: Paleoceanographic Implications

et al. 2022

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In this study, we used stable isotopes of oxygen (δ18O), deuterium (δD), and dissolved inorganic carbon (δ13CDIC) in combination with temperature, salinity, oxygen, and nutrient concentrations to characterize the coastal (71°–78°W) and an oceanic (82°–98°W) water masses (SAAW—Subantarctic Surface Water; STW—Subtropical Water; ESSW—Equatorial Subsurface water; AAIW—Antarctic Intermediate Water; PDW—Pacific Deep Water) of the Southeast Pacific (SEP). The results show that δ18O and δD can be used to differentiate between SAAW‐STW, SAAW‐ESSW, and ESSW‐AAIW. δ13CDIC signatures can be used to differentiate between STW‐ESSW (oceanic section), SAAW‐ESSW, ESSW‐AAIW, and AAIW‐PDW. Compared with the oceanic section, our new coastal section highlights differences in both the chemistry and geometry of water masses above 1,000 m. Previous paleoceanographic studies using marine sediments from the SEP continental margin used the present‐day hydrological oceanic transect to compare against, as the coastal section was not sufficiently characterized. We suggest that our new results of the coastal section should be used for past characterizations of the SEP water masses that are usually based on continental margin sediment samples.

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