Transformation of dissolved organic matter and related trace elements in the mouth zone of the largest European Arctic river: experimental modeling

Shirokova, Liudmila S.; Chupakova, Anna A.; Chupakov, Artem V.; Pokrovsky, Oleg S.

doi:10.1080/20442041.2017.1329907

Cited by 21 publications

(13 citation statements)

References 54 publications

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“…However, small stream and permafrost subsidence remain clearly at the very low edge of BDOC % lost reported for soils and streams in summer. In the estuarine zone of largest European Arctic permafrost-free river, Severnaya Dvina, there was no measurable biodegradation in spring, when the DOM was dominated by allochthonous sources, but a 15 to 20% decrease of DOC occurred during first 300 h in river water collected in August, when sizeable phytoplankton productivity was observed (Shirokova et al, 2017b). In laboratory experiments with individual cultures, moss and peat leachates were also sizably biodegraded over 1-2 days of exposure (Shirokova et al, 2017a), whereas the same bacterial species were not capable degrading DOM from surface waters draining peatland and moss covered bogs (Oleinikova et al, 2018).…”

Section: Another Important Point Revealed In Previous Work On Biodegrmentioning

confidence: 94%

“…To account for possible microbial development in biodegradation experiments, we performed oligotrophic and eutrophic bacteria count in the course of incubation, following the standard methodology used in biodegradation experiments of peat waters (Stutter et al, 2013) as also decsribed previously (Shirokova et al, 2017b;Chupakova et al, 2018). In addition, we Biogeosciences Discuss., https://doi.org/10.5194/bg-2018-528 Manuscript under review for journal Biogeosciences Discussion started: 14 January 2019 c Author(s) 2019.…”

Section: Analyses and Treatmentmentioning

confidence: 99%

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Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

Shirokova¹,

Chupakov²,

Zabelina³

et al. 2019

Preprint

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Abstract. Bio- and photo-degradation of dissolved organic matter (DOM) is identified as dominant vector of C cycle in boreal and high-latitude surface waters. In contrast to large number of studies of humic waters from permafrost-free regions and oligotrophic waters from permafrost-bearing regions, the bio- and photo-lability of DOM from humic surface waters of permafrost-bearing regions has not been thoroughly evaluated. Following standardized methods, we measured biodegradation (low, intermediate, high temperature) and photodegradation (one intermediate temperature) of DOM in surface waters along the hydrological continuum (depression &#8594; stream &#8594; thermokarst lake &#8594; river Pechora) within a European Russian frozen peatland. In all systems, there was no measurable (&#8805;&#8201;10&#8201;%) bio- or photodegradation of DOM over 1 month of incubation. It is possible that the main cause of the lack of degradation is the dominance of allochthonous refractory (soil, peat) DOM in all studied waters. Yet, all surface waters were supersaturated with CO2. Thus, this study suggest that, rather than bio- and photo-degradation of DOM in the water column, other factors such as peat porewater DOM processing and respiration of sediments are the main drivers of elevated pCO2 and emission in humic boreal waters of frozen peat bogs.

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Section: Another Important Point Revealed In Previous Work On Biodegrmentioning

confidence: 94%

Section: Analyses and Treatmentmentioning

confidence: 99%

Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

Shirokova¹,

Chupakov²,

Zabelina³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, small stream and permafrost subsidence clearly remain at the very low end of BDOC % loss reported for soils and streams in summer. In the estuarine zone of largest European Arctic permafrostfree river, the Severnaya Dvina, there was no measurable biodegradation in spring, when the DOM was dominated by allochthonous sources, but a 15 % to 20 % decrease of DOC occurred during first 300 h in river water collected in August, when sizable phytoplankton productivity was observed (Shirokova et al, 2017b). In laboratory experiments with individual cultures, moss and peat leachates were also sizably biodegraded over 1-2 d of exposure (Shirokova et al, 2017a), whereas the same bacterial species were not capable of degrading DOM from surface waters draining peatland and moss-covered bogs (Oleinikova et al, 2018).…”

Section: High Stability Of Dom To Biodegradation In Surface Waters Frmentioning

confidence: 97%

“…To account for possible microbial development in biodegradation experiments, we performed an oligotrophic and eutrophic bacteria count during the course of incubation, following the standard methodology used in biodegradation experiments of peat waters (Stutter et al, 2013), as described previously (Shirokova et al, 2017b;Chupakova et al, 2018). In addition, we measured the total bacterial number and quantified the dominant cell size morphology using the DAPI fluorescence method (Porter and Feig, 1980).…”

Section: Analyses and Treatmentmentioning

confidence: 99%

Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

et al. 2019

Self Cite

View full text Add to dashboard Cite

Abstract. In contrast to the large number of studies on humic waters from permafrost-free regions and oligotrophic waters from permafrost-bearing regions, the bio- and photolability of DOM from the humic surface waters of permafrost-bearing regions has not been thoroughly evaluated. Following standardized protocol, we measured biodegradation (at low, intermediate and high temperatures) and photodegradation (at one intermediate temperature) of DOM in surface waters along the hydrological continuum (depression → stream → thermokarst lake → Pechora River) within a frozen peatland in European Russia. In all systems, within the experimental resolution of 5 % to 10 %, there was no bio- or photodegradation of DOM over a 1-month incubation period. It is possible that the main cause of the lack of degradation is the dominance of allochthonous refractory (soil, peat) DOM in all waters studied. However, all surface waters were supersaturated with CO2. Thus, this study suggests that, rather than bio- and photodegradation of DOM in the water column, other factors such as peat pore-water DOM processing and respiration of sediments are the main drivers of elevated pCO2 and CO2 emission in humic boreal waters of frozen peat bogs.

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“…Furthermore, in contrast to Greenland, several proglacial streams in Iceland have a relatively long flow path from the glacial terminus to the Atlantic Ocean, which may result in the input of additional terrestrial DOC inputs from the increasingly unglaciated downstream catchment area. This may impact the composition and bioavailability of OC along these streams [35,36]. However, their OC composition and concentration remain largely unknown.…”

Section: Introductionmentioning

confidence: 99%

Dissolved and Particulate Organic Carbon in Icelandic Proglacial Streams: A First Estimate

Chifflard

Fasching

Reiss

et al. 2019

Water

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Here for the first time, we analyze the concentration of dissolved (DOC) and particulate organic carbon (POC), as well as its optical properties (absorbance and fluorescence) from several proglacial streams across Iceland, the location of Europe’s largest non-polar ice cap. We found high spatial variability of DOC concentrations and dissolved organic matter (DOM) composition during peak melt, sampling 13 proglacial streams draining the 5 main Icelandic glaciers. Although glacial-derived organic matter (OM) was dominated by proteinaceous florescence, organic matter composition was variable among glaciers, often exhibiting relatively higher aromatic content and increased humification (based on absorbance and fluorescence measurements) closer to the glacier terminus, modulated by the presence of glacial lakes. Additional sampling locations the in flow path of the river Hvitá revealed that while POC concentrations decreased downstream, DOC concentrations and the autochthonous fraction of OM increased, suggesting the reworking of the organic carbon by microbial communities, with likely implications for downstream ecosystems as glaciers continue to melt. Based on our measured DOC concentrations ranging from 0.11 mg·L−1 to 0.94 mg·L−1, we estimate a potential annual carbon release of 0.008 ± 0.002 Tg·C·yr−1 from Icelandic glaciers. This non-conservative first estimate serves to highlight the potentially significant contribution of Icelandic pro-glacial streams to the global carbon cycle and the need for the quantification and determination of the spatio-temporal variation of DOC and POC fluxes and their respective drivers, particularly in light of increased rates of melting due to recent trends in climatic warming.

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Transformation of dissolved organic matter and related trace elements in the mouth zone of the largest European Arctic river: experimental modeling

Cited by 21 publications

References 54 publications

Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

Humic surface waters of frozen peat bogs (permafrost zone) are highly resistant to bio- and photodegradation

Dissolved and Particulate Organic Carbon in Icelandic Proglacial Streams: A First Estimate

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