Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems
Aquatic systems worldwide receive large amounts of organic carbon from terrestrial sources. This ‘allochthonous’ organic carbon (AlloOC) affects critical physical and chemical properties of freshwater ecosystems, with consequences for food web structures and exchange of greenhouse gases with the atm...
Main Author: | |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
Ekologi, miljö och geovetenskap
2009
|
Subjects: | |
Online Access: | http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30051 |
id |
ftumeauniv:oai:DiVA.org:umu-30051 |
---|---|
record_format |
openpolar |
spelling |
ftumeauniv:oai:DiVA.org:umu-30051 2023-10-09T21:54:36+02:00 Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems Berggren, Martin 2009 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30051 eng eng Ekologi, miljö och geovetenskap Umeå : Umeå universitet, Institutionen för ekologi, miljö och geovetenskap http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30051 urn:isbn:978-91-7264-870-8 info:eu-repo/semantics/openAccess lakes streams boreal bacterial respiration bacterial production bacterial growth efficiency allochthonous organic carbon low molecular weight compounds Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2009 ftumeauniv 2023-09-22T13:49:45Z Aquatic systems worldwide receive large amounts of organic carbon from terrestrial sources. This ‘allochthonous’ organic carbon (AlloOC) affects critical physical and chemical properties of freshwater ecosystems, with consequences for food web structures and exchange of greenhouse gases with the atmosphere. In the boreal region, loadings of AlloOC are particularly high due to leaching from huge organic deposits in boreal forest, mire and tundra soils. A main process of AlloOC turnover in aquatic systems is its use by heterotrophic bacteria. Applying a bioassay approach, I measured the respiration and growth (production) of bacteria in northern Sweden, in streams and lakes almost totally dominated by AlloOC. The objective was to elucidate how variations in AlloOC source, age, composition and concentration impact on its use by aquatic bacteria, and how AlloOC properties, in turn, are regulated by landscape composition and by hydrology. The bacterial respiration (30-309 µg C L-1 d-1) was roughly proportional to the concentration of AlloOC (7-47 mg C L-1), but not significantly related to AlloOC source or character. Bacterial production (4-94 µg C L-1 d-1), on the other hand, was coupled to the AlloOC character, rather than concentration. A strong coupling to AlloOC character was also found for bacterial growth efficiency (0.06-0.51), i.e. production per unit of assimilated carbon. Bacterial production and growth efficiency increased with rising concentrations of low molecular weight AlloOC (carboxylic acids, free amino acids and simple carbohydrates). While the total AlloOC concentrations generally were the highest in mire-dominated catchments, low molecular weight AlloOC concentrations were much higher in forested catchments, compared to mire-dominated. These patterns were reflected in a strong landscape control of aquatic bacterial metabolism. Moreover, high flow episodes increased the export of organic carbon from forests, in relation to the export from mires, stimulating the bacterial production and growth ... Doctoral or Postdoctoral Thesis Northern Sweden Tundra Umeå University: Publications (DiVA) |
institution |
Open Polar |
collection |
Umeå University: Publications (DiVA) |
op_collection_id |
ftumeauniv |
language |
English |
topic |
lakes streams boreal bacterial respiration bacterial production bacterial growth efficiency allochthonous organic carbon low molecular weight compounds |
spellingShingle |
lakes streams boreal bacterial respiration bacterial production bacterial growth efficiency allochthonous organic carbon low molecular weight compounds Berggren, Martin Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
topic_facet |
lakes streams boreal bacterial respiration bacterial production bacterial growth efficiency allochthonous organic carbon low molecular weight compounds |
description |
Aquatic systems worldwide receive large amounts of organic carbon from terrestrial sources. This ‘allochthonous’ organic carbon (AlloOC) affects critical physical and chemical properties of freshwater ecosystems, with consequences for food web structures and exchange of greenhouse gases with the atmosphere. In the boreal region, loadings of AlloOC are particularly high due to leaching from huge organic deposits in boreal forest, mire and tundra soils. A main process of AlloOC turnover in aquatic systems is its use by heterotrophic bacteria. Applying a bioassay approach, I measured the respiration and growth (production) of bacteria in northern Sweden, in streams and lakes almost totally dominated by AlloOC. The objective was to elucidate how variations in AlloOC source, age, composition and concentration impact on its use by aquatic bacteria, and how AlloOC properties, in turn, are regulated by landscape composition and by hydrology. The bacterial respiration (30-309 µg C L-1 d-1) was roughly proportional to the concentration of AlloOC (7-47 mg C L-1), but not significantly related to AlloOC source or character. Bacterial production (4-94 µg C L-1 d-1), on the other hand, was coupled to the AlloOC character, rather than concentration. A strong coupling to AlloOC character was also found for bacterial growth efficiency (0.06-0.51), i.e. production per unit of assimilated carbon. Bacterial production and growth efficiency increased with rising concentrations of low molecular weight AlloOC (carboxylic acids, free amino acids and simple carbohydrates). While the total AlloOC concentrations generally were the highest in mire-dominated catchments, low molecular weight AlloOC concentrations were much higher in forested catchments, compared to mire-dominated. These patterns were reflected in a strong landscape control of aquatic bacterial metabolism. Moreover, high flow episodes increased the export of organic carbon from forests, in relation to the export from mires, stimulating the bacterial production and growth ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Berggren, Martin |
author_facet |
Berggren, Martin |
author_sort |
Berggren, Martin |
title |
Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
title_short |
Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
title_full |
Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
title_fullStr |
Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
title_full_unstemmed |
Bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
title_sort |
bacterial use of allochthonous organic carbon for respiration and growth in boreal freshwater systems |
publisher |
Ekologi, miljö och geovetenskap |
publishDate |
2009 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30051 |
genre |
Northern Sweden Tundra |
genre_facet |
Northern Sweden Tundra |
op_relation |
http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-30051 urn:isbn:978-91-7264-870-8 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1779318245940002816 |