Geochemistry of Peruvian near-surface sediments

Böning, Philipp; Brumsack, Hans‐Jürgen; Böttcher, Michael E.; Schnetger, Bernhard; Kriete, Cornelia; Kallmeyer, Jens; Borchers, S. L.

doi:10.1016/j.gca.2004.04.027

Cited by 351 publications

(228 citation statements)

References 111 publications

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“…Surface particulate organic carbon (POC) content is high in the OMZ (15 to 20 wt.%) with lower values (5 to 10 wt.%) on the shelf and in deep waters (Böning et al, 2004). δ 13 C analysis and other geochemical indicators confirm that the organic matter at this latitude is almost entirely of marine origin (Arthur et al, 1998;Levin et al, 2002).…”

Section: Site Descriptionmentioning

confidence: 91%

“…Sediments nearby the time-series station are diatomaceous, rapidly accumulating muds displaying high rates of microbial sulfate reduction (Suess et al, 1987;Fossing, 1990;Böning et al, 2004). Surface particulate organic carbon (POC) content is high in the OMZ (15 to 20 wt.%) with lower values (5 to 10 wt.%) on the shelf and in deep waters (Böning et al, 2004).…”

Section: Site Descriptionmentioning

confidence: 99%

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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: Site Descriptionmentioning

confidence: 91%

Section: Site Descriptionmentioning

confidence: 99%

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

2017

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“…Böning et al (2004) (Niggemann et al, 2007). Clearly, there is pronounced spatial heterogeneity in the total organic matter degradation rate in the OMZ off Peru and Chile.…”

Section: Sediment Geochemistry and Pom Degradationmentioning

confidence: 99%

“…The volume fraction of the sediment was calculated using a dry sediment density of 2 g cm -3 (Böning et al, 2004). Further analytical details corresponding to the benthic lander deployments are described by Sommer et al (submitted).…”

Section: Sampling and Geochemical Analysismentioning

confidence: 99%

Benthic nitrogen cycling traversing the Peruvian oxygen minimum zone

Bohlen

Dale

Sommer

et al. 2011

Geochimica et Cosmochimica Acta

107

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“…However at low T eff , T effPOP remains much higher than 6% (15%), corresponding to a decrease from the intermediate range five times lower than for the other elements. This indicates a relative accumulation of phosphorus, suggesting that in remineralisation-like configuration, phosphorus material remains more 10 refractory than for the other components, such as the more labile nitrogen-rich amino-acids material preferentially degraded (Van Mooy et al, 2002;Böning et al, 2004;Pantoja et al, 2004;Diaz et al, 2008). In the preservation-like configurations (high T eff ), T effCaCO3 becomes higher than 100% (133%), suggesting a potential accumulation and/or aggregation of calcium carbonate particles (e.g.…”

mentioning

confidence: 99%

Modulation of the vertical particles transfer efficiency in the Oxygen Minimum Zone off Peru

Bretagnon¹,

Paulmier²,

Garçon³

et al. 2018

Preprint

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Abstract. The fate of the Organic Matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth&#8217;s system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive Eastern Boundary Upwelling Systems (EBUSs) associated with Oxygen Minimum Zones (OMZs) should foster OM preservation due to low O2 conditions, but their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru, providing high temporal resolution O2 series characterizing two seasonal steady states at the upper trap: suboxic ([O2]&#8201;<&#8201;25&#8201;&#181;mol&#8201;kg&#8722;1) and hypoxic/oxic (15<[O2]&#8201;<&#8201;160&#8201;&#181;mol&#8201;kg&#8722;1) in austral summer and winter/spring, respectively. The OMZ vertical transfer efficiency of Particulate Organic Carbon (POC) between traps (Teff) fits into three main ranges (high, intermediate, low) suggesting that both predominant preservation (high Teff&#8201;>&#8201;50&#8201;%) and remineralisation (intermediate Teff&#8201;20&#8201;<&#8201;50&#8201;% or low Teff&#8201;<&#8201;6&#8201;%) configurations can occur. An efficient OMZ vertical transfer (Teff&#8201;>&#8201;50&#8201;%) has been reported in summer and winter associated with extreme limitation in O2 concentrations or OM quantity for OM degradation. However, higher levels of O2 or OM, or less refractory OM, at the oxycline, even in a co-limitation context, can decrease the OMZ transfer efficiency below 50&#8201;%, especially in summer during intraseasonal wind-driven oxygenation events. In late winter and early spring, high oxygenation conditions together with high fluxes of sinking particles trigger a shutdown of the OMZ transfer (Teff&#8201;<&#8201;6&#8201;%). Transfer efficiency of chemical elements composing the majority of the flux (nitrogen, phosphorus, silica, calcium carbonate) follows the same trend than for carbon, with the lowest transfer late winter and early spring. In terms of particulate isotopes, vertical transfer of &#948;15N suggests a complex behaviour of 15N impoverishment or enrichment according to Teff modulation. This OM fate sensitivity to O2 fluctuations and particles concentration calls for further investigations on OM and O2-driven remineralisation processes and the consideration of intermittent OMZ behaviour on OM in past studies and climate projections.

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Geochemistry of Peruvian near-surface sediments

Cited by 351 publications

References 111 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)

Benthic nitrogen cycling traversing the Peruvian oxygen minimum zone

Modulation of the vertical particles transfer efficiency in the Oxygen Minimum Zone off Peru

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