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In situ plankton community respiration measurements show low respiratory quotients in a eutrophic lake

Münzner, Karla LU and Berggren, Martin LU (2019) In Environmental Microbiology 21(4). p.1425-1435
Abstract


Planktonic community respiration is an important carbon cycling process, typically quantified by converting measured values of dissolved O
2
consumption rates into CO
2
production rates assuming a respiratory quotient of 1 (RQ = CO
2
per O
... (More)


Planktonic community respiration is an important carbon cycling process, typically quantified by converting measured values of dissolved O
2
consumption rates into CO
2
production rates assuming a respiratory quotient of 1 (RQ = CO
2
per O
2
by moles). However, the true variability in planktonic RQs between different aquatic ecosystems is poorly understood. We conducted in situ RQ measurements in a eutrophic lake dominated by algal-derived substances and found that RQs were significantly below 1. In fact, many RQ values were extremely low (0.2–0.6), below theoretical RQs for oxidation of algal organic matter substrates (0.7–0.8), suggesting that other factors than substrate control need to be considered to understand the RQ. This view was further supported by lack of correlations between RQ and microbial variables known to be strongly substrate dependent, including bacterial growth efficiency and the functional capacity of the bacterioplankton community to degrade different compounds. Based on the measured dynamics in methane and nutrient pools, we discuss that methane oxidation and nitrification likely occurred in the lake, contributing to the unusually low RQs. Our findings demonstrate that planktonic RQs in productive lakes can systematically be below 1, suggesting that CO
2
emissions from these lakes may currently be overestimated.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Environmental Microbiology
volume
21
issue
4
pages
1425 - 1435
publisher
Wiley-Blackwell
external identifiers
  • scopus:85063108399
  • pmid:30816622
ISSN
1462-2912
DOI
10.1111/1462-2920.14574
language
English
LU publication?
yes
id
801a10fa-c42c-480d-be64-0651f5c379c4
date added to LUP
2019-03-28 14:19:31
date last changed
2020-01-13 01:35:29
@article{801a10fa-c42c-480d-be64-0651f5c379c4,
  abstract     = {<p><br>
                                                         Planktonic community respiration is an important carbon cycling process, typically quantified by converting measured values of dissolved O                             <br>
                            <sub>2</sub><br>
                                                          consumption rates into CO                             <br>
                            <sub>2</sub><br>
                                                          production rates assuming a respiratory quotient of 1 (RQ = CO                             <br>
                            <sub>2</sub><br>
                                                          per O                             <br>
                            <sub>2</sub><br>
                                                          by moles). However, the true variability in planktonic RQs between different aquatic ecosystems is poorly understood. We conducted in situ RQ measurements in a eutrophic lake dominated by algal-derived substances and found that RQs were significantly below 1. In fact, many RQ values were extremely low (0.2–0.6), below theoretical RQs for oxidation of algal organic matter substrates (0.7–0.8), suggesting that other factors than substrate control need to be considered to understand the RQ. This view was further supported by lack of correlations between RQ and microbial variables known to be strongly substrate dependent, including bacterial growth efficiency and the functional capacity of the bacterioplankton community to degrade different compounds. Based on the measured dynamics in methane and nutrient pools, we discuss that methane oxidation and nitrification likely occurred in the lake, contributing to the unusually low RQs. Our findings demonstrate that planktonic RQs in productive lakes can systematically be below 1, suggesting that CO                             <br>
                            <sub>2</sub><br>
                                                          emissions from these lakes may currently be overestimated.                         <br>
                        </p>},
  author       = {Münzner, Karla and Berggren, Martin},
  issn         = {1462-2912},
  language     = {eng},
  number       = {4},
  pages        = {1425--1435},
  publisher    = {Wiley-Blackwell},
  series       = {Environmental Microbiology},
  title        = {In situ plankton community respiration measurements show low respiratory quotients in a eutrophic lake},
  url          = {http://dx.doi.org/10.1111/1462-2920.14574},
  doi          = {10.1111/1462-2920.14574},
  volume       = {21},
  year         = {2019},
}