Fermentation and Anaerobic Oxidation of Organic Carbon in the Oxygen Minimum Zone of the Upwelling Ecosystem Off Concepción, in Central Chile

Srain, Benjamín; Sobarzo, Marcus; Daneri, Giovanni; González, Humberto E.; Testa, Giovanni; Schwarz, Alex; Pérez, Norma; Pantoja-Gutiérrez, Silvio

doi:10.3389/fmars.2020.00533

Cited by 16 publications

(12 citation statements)

References 136 publications

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“…In the study area, upwelling not only fertilizes the surface with high-nutrient content waters fueling primary and secondary productivity (e.g., Montero et al, 2007), but also develops a seasonal oxygen deficiency in the subsurface associated with Equatorial Subsurface Waters (ESSW) which was evident during our study (Ahumada and Chuecas, 1979;Sobarzo et al, 2007). Oxygen has been reported as a controlling factor of microbial community abundance (Eissler et al, 2010), structure (Aldunate et al, 2018), and biogeochemical active processes (Galán et al, 2014(Galán et al, , 2017Srain et al, 2020) in the study area. During our study, GAMLSS analyses indicated that the spatiotemporal variability in non-photosynthetic picoplanktonic cell abundance (studied by flow cytometry) was significant in the study area, and among the variables studied, oxygen and nitrite largely account for the changes observed (Table 1).…”

Section: Discussionmentioning

confidence: 59%

Spatiotemporal Distribution of Key Pelagic Microbes in a Seasonal Oxygen-Deficient Coastal Upwelling System of the Eastern South Pacific Ocean

et al. 2020

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Section: Discussionmentioning

confidence: 59%

Spatiotemporal Distribution of Key Pelagic Microbes in a Seasonal Oxygen-Deficient Coastal Upwelling System of the Eastern South Pacific Ocean

et al. 2020

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“…Our results therefore imply that nonnitrate-based and nitrite-based respiratory processes lead to organic nitrogen remineralization within the particles. Such processes might be microaerobic respiration by prokaryotes [64][65][66] , and microzooplankton transported within particles, or fermentation, which has recently been shown to be a significant source of ammonium within the Eastern Tropical South Pacific OMZ 67 .…”

Section: Abundance and Characterization Of Sinking Organic Materialmentioning

confidence: 99%

Small sinking particles control anammox rates in the Peruvian oxygen minimum zone

et al. 2021

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Anaerobic oxidation of ammonium (anammox) in oxygen minimum zones (OMZs) is a major pathway of oceanic nitrogen loss. Ammonium released from sinking particles has been suggested to fuel this process. During cruises to the Peruvian OMZ in April–June 2017 we found that anammox rates are strongly correlated with the volume of small particles (128–512 µm), even though anammox bacteria were not directly associated with particles. This suggests that the relationship between anammox rates and particles is related to the ammonium released from particles by remineralization. To investigate this, ammonium release from particles was modelled and theoretical encounters of free-living anammox bacteria with ammonium in the particle boundary layer were calculated. These results indicated that small sinking particles could be responsible for ~75% of ammonium release in anoxic waters and that free-living anammox bacteria frequently encounter ammonium in the vicinity of smaller particles. This indicates a so far underestimated role of abundant, slow-sinking small particles in controlling oceanic nutrient budgets, and furthermore implies that observations of the volume of small particles could be used to estimate N-loss across large areas.

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“…During this process, microorganisms may exhibit a preference for utilizing the carbon found in carbohydrates over the available nitrogen. This preference can result in a higher C:N ratio in the fermentation products (Srain et al., 2020). Collectively, these processes contribute to an elevated C:N ratio in POM (Cavan et al., 2017; Srain et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

“…This preference can result in a higher C:N ratio in the fermentation products (Srain et al., 2020). Collectively, these processes contribute to an elevated C:N ratio in POM (Cavan et al., 2017; Srain et al., 2020).…”

Section: Discussionmentioning

confidence: 99%

Particulate Organic Matter in the Atacama Trench: Tracing Sources and Possible Transport Mechanisms to the Hadal Seafloor

Flores,

Fernández‐Urruzola,

Cantarero

et al. 2023

JGR Biogeosciences

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Oceanic trenches are an important sink for organic matter (OM). However, little is known about how much of the OM reaching the hadal region derives from the sunlit surface ocean and other sources. We provide new insight into the OM sources in the Atacama Trench by examining the elemental and stable isotope composition of carbon and nitrogen in bulk OM throughout the entire water column and down to bathyal and hadal sediments. Moreover, we estimated the particulate organic carbon (POC) concentration and downward carbon flux. Our results, based on two‐way variance analysis, showed statistical differences in δ15NPON between the epipelagic zone and the deep zones. However, no statistical differences in δ13CPOC and C:N ratio between hadalpelagic and shallower pelagic zones were found, except for δ13CPOC in the oxygen deficient zone. On the contrary, whereas the isotopic signatures of hadal sediments were distinct from those over the entire water column, they were similar to the values in bathyal sediments. Thus, our results suggest that bathyal sediments could contribute more OM to hadal sediments than the different zones of the water column. Indeed, whereas POC flux estimates derived from remote sensing data indicate that ∼16‐27% of POC could evade surface remineralization within the top 200 m and potentially be exported to depths beyond the mesopelagic region, model estimates suggest that ∼3.3% of it could reach hadal depths. Our results provide a quantitative baseline of pelagic‐benthic coupling which can aid in assessment of carbon cycling changes in future climate scenarios.

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Fermentation and Anaerobic Oxidation of Organic Carbon in the Oxygen Minimum Zone of the Upwelling Ecosystem Off Concepción, in Central Chile

Cited by 16 publications

References 136 publications

Spatiotemporal Distribution of Key Pelagic Microbes in a Seasonal Oxygen-Deficient Coastal Upwelling System of the Eastern South Pacific Ocean

Spatiotemporal Distribution of Key Pelagic Microbes in a Seasonal Oxygen-Deficient Coastal Upwelling System of the Eastern South Pacific Ocean

Small sinking particles control anammox rates in the Peruvian oxygen minimum zone

Particulate Organic Matter in the Atacama Trench: Tracing Sources and Possible Transport Mechanisms to the Hadal Seafloor

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