Influence of water column dynamics on sulfide oxidation and other major biogeochemical processes in the chemocline of Mariager Fjord (Denmark)

Zopfi, Jakob; Ferdelman, Timothy G.; Jørgensen, Bo Barker; Teske, Andreas; Thamdrup, Bo

doi:10.1016/s0304-4203(00)00091-8

Cited by 143 publications

(126 citation statements)

References 66 publications

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“…Transient dynamics in Saanich Inlet can exhibit significantly higher nitrogen fluxes and chemoautotrophic activity (34), which might further explain discrepancies between the model and measured DCA rates. Accounting for chemoautotrophic productivity based on oxidant and reductant supply in redox transition zones is generally difficult because of limited knowledge on active pathways, the possibility of cryptic nutrient cycling, and potential lateral substrate intrusions, and discrepancies similar to our study are frequently reported for other OMZs (35)(36)(37)(38). Hence, fully accounting for measured DCA rates remains an unresolved problem with important implications for carbon cycling in OMZs.…”

Section: Dna Profiles and Process Ratesmentioning

confidence: 44%

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Louca

Hawley

Katsev

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

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Microorganisms are the most abundant lifeform on Earth, mediating global fluxes of matter and energy. Over the past decade, high-throughput molecular techniques generating multiomic sequence information (DNA, mRNA, and protein) have transformed our perception of this microcosmos, conceptually linking microorganisms at the individual, population, and community levels to a wide range of ecosystem functions and services. Here, we develop a biogeochemical model that describes metabolic coupling along the redox gradient in Saanich Inlet-a seasonally anoxic fjord with biogeochemistry analogous to oxygen minimum zones (OMZs). The model reproduces measured biogeochemical process rates as well as DNA, mRNA, and protein concentration profiles across the redox gradient. Simulations make predictions about the role of ubiquitous OMZ microorganisms in mediating carbon, nitrogen, and sulfur cycling. For example, nitrite "leakage" during incomplete sulfide-driven denitrification by SUP05 Gammaproteobacteria is predicted to support inorganic carbon fixation and intense nitrogen loss via anaerobic ammonium oxidation. This coupling creates a metabolic niche for nitrous oxide reduction that completes denitrification by currently unidentified community members. These results quantitatively improve previous conceptual models describing microbial metabolic networks in OMZs. Beyond OMZ-specific predictions, model results indicate that geochemical fluxes are robust indicators of microbial community structure and reciprocally, that gene abundances and geochemical conditions largely determine gene expression patterns. The integration of real observational data, including geochemical profiles and process rate measurements as well as metagenomic, metatranscriptomic and metaproteomic sequence data, into a biogeochemical model, as shown here, enables holistic insight into the microbial metabolic network driving nutrient and energy flow at ecosystem scales.M icrobial communities catalyze Earth's biogeochemical cycles through metabolic pathways that couple fluxes of matter and energy to biological growth (1). These pathways are encoded in evolving genes that, over time, spread across microbial lineages and today shape the conditions for life on Earth. High-throughput sequencing and mass-spectrometry platforms are generating multiomic sequence information (DNA, mRNA, and protein) that is transforming our perception of this microcosmos, but the vast majority of environmental sequencing studies lack a mechanistic link to geochemical processes. At the same time, mathematical models are increasingly used to describe local-and global-scale biogeochemical processes or predict future changes in global elemental cycling and climate (2, 3). Although these models typically incorporate the catalytic properties of cells, they fail to integrate the information flow from DNA to mRNA, proteins, and process rates as described by the central dogma of molecular biology (4). Hence, a mechanistic framework integrating multiomic data with geochemical information has...

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Section: Dna Profiles and Process Ratesmentioning

confidence: 44%

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Louca

Hawley

Katsev

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

120

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“…In the Black Sea, integrated chemolithoautotroph rates in the range of 300 to 800 mg C m −2 d −1 were measured and accounted for 50 to 80% of the primary production, whereas in the Cariaco Basin, dark CA represented on average 70% of the primary production. Likewise, in the Mariager Fjord, dark CA accounted for 37% of total C fixation, but rates were as high as 1.092 mg C m −3 d −1 , leading to the possibility of an important heterotrophic CA activity within a narrow chemocline (Zopfi et al, 2001). Our rates fall in the highest range of these measurements (for comparison, see Table 4).…”

Section: What Is the Relative Importance Of Chemo-vs Photoautotrophimentioning

confidence: 66%

“…a Total dark CA in the whole water column (integration from surface to 92 m depth). Dark CA, which has been also observed at high rates in some redoxclines (e.g., Zopfi et al, 2001), was explored during this study as a possible explanation for such variability. Oxygen is undoubtedly a chemical forcing factor in this coastal upwelling ecosystem because of the tight link between its vertical distribution and its consumption due to the respiration of sinking POC.…”

Section: Discussionmentioning

confidence: 99%

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem

Farı́as¹,

Fernández

Faúndez³

et al. 2009

Biogeosciences

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Abstract. The high availability of electron donors occurring in coastal upwelling ecosystems with marked oxyclines favours chemoautotrophy, in turn leading to high N 2 O and CH 4 cycling associated with aerobic NH + 4 (AAO) and CH 4 oxidation (AMO). This is the case of the highly productive coastal upwelling area off central Chile (36 • S), where we evaluated the importance of total chemolithoautotrophic vs. photoautotrophic production, the specific contributions of AAO and AMO to chemosynthesis and their role in gas cycling. Chemolithoautotrophy was studied at a time-series station during monthly (2007)(2008)(2009)) and seasonal cruises (January 2008, September 2008, January 2009) and was assessed in terms of the natural C isotopic ratio of particulate organic carbon (δ 13 POC), total and specific (associated with AAO and AMO) dark carbon assimilation (CA), and N 2 O and CH 4 cycling experiments. At the oxycline, δ 13 POC averaged −22.2‰; this was significantly lighter compared to the surface (−19.7‰) and bottom layers (−20.7‰). Total integrated dark CA in the whole water column fluctuated between 19.4 and 2.924 mg C m −2 d −1 , was higher during active upwelling, and contributed 0.7 to 49.7% of the total integrated autotrophic CA (photo plus chemoautotrophy), which ranged from 135 to 7.626 mg C m −2 d −1 , and averaged 20.3% for the whole sampling period. Dark CA was reduced by 27 to 48% after adding a specific AAO inhibitor (ATU) and by 24 to 76% with GC7, a specific archaea inhibitor. This indicates that AAO and AMO microbes (most of them archaea) were performing dark CA through the oxidation of NH

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“…Other sources of oxygen are then utilized, including nitrate. Suboxic regimes have been observed in the Black Sea, where horizontal ventilation again appears to be the formation mechanism (Konovalov et al 2003), and in Mariager Fjord, where they were assumed to be caused by photosynthetic sulfur bacteria that use up the sulfide or by temporal imbalances in fluxes of redox species (Ramsing et al 1996; but see also Zopfi et al 2001). Although the advection of individual ocean-water parcels along Nitinat Lake is slow, their volume is compensated for by a general rise in shallow isopycnals everywhere, leading to a thinning of the oxic layer at the inshore end of Nitinat Lake (Fig.…”

Section: Discussionmentioning

confidence: 99%

Physical, chemical, and microbial regimes in an anoxic fjord (Nitinat Lake)

Pawlowicz

Baldwin

Muttray

et al. 2007

Limnology & Oceanography

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New observations of physical, biological, and chemical parameters were obtained between July 2003 and February 2005 in Nitinat Lake, British Columbia, a permanently anoxic seawater fjord. These observations include continuous profiles of nitrate and bisulfide using a new instrument for in situ ultraviolet spectrophotometry. Anoxic seawaters in this 200-m-deep basin can be found as shallow as 7 m. However, Nitinat Lake is surprisingly dynamic, with a deep-water renewal time of only about 5 yr and significant spatial and temporal variability. Exchange with the ocean is limited by the size of the linking channel, and during low tides the outflow is subject to an hydraulic control. This nonlinearity causes a relatively large fortnightly cycle in water level and explains flooding events associated with heavy rainstorms. In addition, the restricted flow makes deep-water renewal gradual so that anoxic conditions are preserved. Intermediate waters (5-40 m in depth) are renewed alternately by oxygenation from surface mixing in winter and by upwelling of anoxic water and horizontal inflow of subducted ocean water in summer. The horizontal inflow results in a subsurface region of suboxic water in mid-fjord during summer. No suboxic regime is evident at either the river end of Nitinat Lake (where oxygen and sulfide-rich regions adjoin in a nitrate-depleted water column) or at the ocean end of Nitinat Lake (where oxygen and nitrate-rich regions sometimes overlap with sulfide-rich regions). Maximum phytoplankton levels near the surface are high in both winter and summer. A second peak in biological activity appears near the anoxic boundary, possibly as a result of sulfur-oxidizing bacteria. Sulfate-reducing bacteria are also present in anoxic water in both seasons and just above the oxic/anoxic interface in winter and just above the suboxic/anoxic interface in summer.

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Influence of water column dynamics on sulfide oxidation and other major biogeochemical processes in the chemocline of Mariager Fjord (Denmark)

Cited by 143 publications

References 66 publications

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem

Physical, chemical, and microbial regimes in an anoxic fjord (Nitinat Lake)

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Influence of water column dynamics on sulfide oxidation and other major biogeochemical processes in the chemocline of Mariager Fjord (Denmark)

Cited by 143 publications

References 66 publications

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Integrating biogeochemistry with multiomic sequence information in a model oxygen minimum zone

Chemolithoautotrophic production mediating the cycling of the greenhouse gases N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; in an upwelling ecosystem

Physical, chemical, and microbial regimes in an anoxic fjord (Nitinat Lake)

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Chemolithoautotrophic production mediating the cycling of the greenhouse gases N<sub>2</sub>O and CH<sub>4</sub> in an upwelling ecosystem