uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Seasonal variability in dissolved organic carbon degradation in boreal lakes: links to composition, sources, and baseline metabolism
Research Center for Watershed - Aquatic Ecosystem Interactions (RIVE), Université du Québec à Trois-Rivières, Québec, Canada.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.ORCID iD: 0000-0002-5884-1684
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Limnology.
(English)Manuscript (preprint) (Other academic)
Keyword [en]
DOC, bacterioplankton, boreal lakes, seasonality, carbon source, baseline metabolism
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:uu:diva-316892OAI: oai:DiVA.org:uu-316892DiVA: diva2:1079255
Available from: 2017-03-08 Created: 2017-03-08 Last updated: 2017-03-08
In thesis
1. Dissolved organic matter in lakes: Chemical diversity and continuum of reactivity
Open this publication in new window or tab >>Dissolved organic matter in lakes: Chemical diversity and continuum of reactivity
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Dissolved organic matter (DOM) is the largest pool of organic carbon in aquatic systems and an important component of the global carbon cycle. Large amounts of DOM are decomposed within lakes, resulting in fluxes of CO2 and CH4 to the atmosphere. Therefore, there is a considerable interest in understanding the controls of DOM decomposition in freshwaters. There is evidence that in lakes intrinsic controls related to DOM composition are of primary importance, yet our knowledge about molecular drivers of DOM degradation is limited. This thesis addresses the link between chemical composition and reactivity of lake DOM by applying an experimental approach, molecular-level DOM characterization, and kinetic modeling of DOM decay.

The first study shows that photoinduced transformations and partial removal of colored aromatic components of DOM have profound effects on DOM degradation kinetics, mediated by the shifts in the relative share of rapidly and slowly degrading DOM fractions. Two following studies estimate exponential decay coefficients for each individual molecular formula identified within bulk DOM. A continuous distribution of exponential decay coefficients is found within bulk DOM, which directly corroborates the central and previously empirically untested assumption behind the reactivity continuum model of DOM decay. Further, individual decay rates are evaluated in connection to specific molecular properties. On average, highly unsaturated and phenolic compounds appear to be more persistent than compounds with higher aromatic content (plant polyphenols and polycondensed aromatics), and aliphatic compounds demonstrate the highest decay rates. The reactivity of aromatics additionally increases with increasing nominal oxidation state of carbon. Molecular analysis further indicates that increasing reactivity of DOM after UV exposure is caused by disintegration of supramolecular complexes. Study IV shows that changes in relative proportion of terrestrial versus algal DOM control degradability of DOM through seasons. Under ice, when algal-derived DOM is maximally depleted, DOM degradation potential converges to similarly low levels, regardless of lake type (productive or humic), and bacterial respiration primarily relies on terrestrial carbon. This suggests a general pattern of baseline metabolism across boreal lakes. I conclude that DOM is a dynamic reactivity continuum and a tight link exists between DOM behavior and compositional properties.

Place, publisher, year, edition, pages
uppsala: Acta Universitatis Upsaliensis, 2017. 44 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1486
Keyword
dissolved organic matter, DOM, dissolved organic carbon, DOC, PARAFAC, reactivity continuum model, ultrahigh resolution mass spectrometry, FT-ICR-MS, organic matter characterization, decomposition kinetics, baseline metabolism
National Category
Natural Sciences
Research subject
Biology with specialization in Limnology
Identifiers
urn:nbn:se:uu:diva-316893 (URN)978-91-554-9840-5 (ISBN)
Public defence
2017-04-28, Friessalen, EBC, Norbyvägen 14, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2017-04-07 Created: 2017-03-08 Last updated: 2017-04-21

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Mostovaya, Alina
By organisation
Limnology
Natural Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 301 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf