Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems
Abstract Many studies assume a respiratory quotient (RQ = molar ratio of CO2 produced to O2 consumed) close to 1 when calculating bacterioplankton respiration. However, evidence suggests that RQ depends on the chemical composition of the respired substrate pool that may be altered by photochemical p...
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| Format: | Article |
| Language: | English |
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Wiley
2016-07-01
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| Series: | Geophysical Research Letters |
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| Online Access: | https://doi.org/10.1002/2016GL069621 |
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| _version_ | 1850134484238729216 |
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| author | Lina Allesson Lena Ström Martin Berggren |
| author_facet | Lina Allesson Lena Ström Martin Berggren |
| author_sort | Lina Allesson |
| collection | DOAJ |
| description | Abstract Many studies assume a respiratory quotient (RQ = molar ratio of CO2 produced to O2 consumed) close to 1 when calculating bacterioplankton respiration. However, evidence suggests that RQ depends on the chemical composition of the respired substrate pool that may be altered by photochemical production of oxygen‐rich substrates, resulting in elevated RQs. Here we conducted a novel study of the impact of photochemical processing of dissolved organic carbon (DOC) on RQ. We monitored the bacterial RQ in bioassays of both ultraviolet light irradiated and nonirradiated humic lake water, using optic gas‐pressure sensors. In the experimentally irradiated samples the average RQ value was significantly higher (3.4–3.5 [±0.4 standard error (SE)]) than that in the dark controls (1.3 [±0.1 SE]). Our results show that the RQ is systematically higher than 1 when the bacterial metabolism in large part is based on photoproducts. By assuming an RQ of 1, bacterioplankton respiration in freshwater ecosystems may be greatly underestimated. |
| format | Article |
| id | doaj-art-8e37a5251f36465c8b21ff778fb9727d |
| institution | OA Journals |
| issn | 0094-8276 1944-8007 |
| language | English |
| publishDate | 2016-07-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geophysical Research Letters |
| spelling | doaj-art-8e37a5251f36465c8b21ff778fb9727d2025-08-20T02:31:41ZengWileyGeophysical Research Letters0094-82761944-80072016-07-0143147538754510.1002/2016GL069621Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystemsLina Allesson0Lena Ström1Martin Berggren2Department of Physical Geography and Ecosystem Science Lund University Lund SwedenDepartment of Physical Geography and Ecosystem Science Lund University Lund SwedenDepartment of Physical Geography and Ecosystem Science Lund University Lund SwedenAbstract Many studies assume a respiratory quotient (RQ = molar ratio of CO2 produced to O2 consumed) close to 1 when calculating bacterioplankton respiration. However, evidence suggests that RQ depends on the chemical composition of the respired substrate pool that may be altered by photochemical production of oxygen‐rich substrates, resulting in elevated RQs. Here we conducted a novel study of the impact of photochemical processing of dissolved organic carbon (DOC) on RQ. We monitored the bacterial RQ in bioassays of both ultraviolet light irradiated and nonirradiated humic lake water, using optic gas‐pressure sensors. In the experimentally irradiated samples the average RQ value was significantly higher (3.4–3.5 [±0.4 standard error (SE)]) than that in the dark controls (1.3 [±0.1 SE]). Our results show that the RQ is systematically higher than 1 when the bacterial metabolism in large part is based on photoproducts. By assuming an RQ of 1, bacterioplankton respiration in freshwater ecosystems may be greatly underestimated.https://doi.org/10.1002/2016GL069621bacterioplankton respirationphotooxidation |
| spellingShingle | Lina Allesson Lena Ström Martin Berggren Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems Geophysical Research Letters bacterioplankton respiration photooxidation |
| title | Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems |
| title_full | Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems |
| title_fullStr | Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems |
| title_full_unstemmed | Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems |
| title_short | Impact of photochemical processing of DOC on the bacterioplankton respiratory quotient in aquatic ecosystems |
| title_sort | impact of photochemical processing of doc on the bacterioplankton respiratory quotient in aquatic ecosystems |
| topic | bacterioplankton respiration photooxidation |
| url | https://doi.org/10.1002/2016GL069621 |
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