Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters
Source at https://doi.org/10.5194/bg-14-1631-2017 . Coastal seas may account for more than 75 % of global oceanic methane emissions. There, methane is mainly produced microbially in anoxic sediments from which it can escape to the overlying water column. Aerobic methane oxidation (MOx) in the water...
Published in: | Biogeosciences |
---|---|
Main Authors: | , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
European Geosciences Union (EGU)
2017
|
Subjects: | |
Online Access: | https://hdl.handle.net/10037/12618 https://doi.org/10.5194/bg-14-1631-2017 |
id |
ftunivtroemsoe:oai:munin.uit.no:10037/12618 |
---|---|
record_format |
openpolar |
spelling |
ftunivtroemsoe:oai:munin.uit.no:10037/12618 2023-05-15T14:27:18+02:00 Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters Steinle, Lea Maltby, Johanna Treude, Tina Kock, Annette Bange, Hermann W. Engbersen, Nadine Zopfi, Jakob Lehmann, Moritz F. Niemann, Helge 2017-03-29 https://hdl.handle.net/10037/12618 https://doi.org/10.5194/bg-14-1631-2017 eng eng European Geosciences Union (EGU) Biogeosciences info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Steinle, L., Maltby, J., Treude, T., Kock, A., Bange, H.W., Engbersen, N., … Niemann, H. (2017). Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters. Biogeosciences, 14:1631-1645. https://doi.org/10.5194/bg-14-1631-2017 FRIDAID 1464756 doi:10.5194/bg-14-1631-2017 1726-4170 1726-4189 https://hdl.handle.net/10037/12618 openAccess VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Journal article Tidsskriftartikkel Peer reviewed 2017 ftunivtroemsoe https://doi.org/10.5194/bg-14-1631-2017 2021-06-25T17:55:39Z Source at https://doi.org/10.5194/bg-14-1631-2017 . Coastal seas may account for more than 75 % of global oceanic methane emissions. There, methane is mainly produced microbially in anoxic sediments from which it can escape to the overlying water column. Aerobic methane oxidation (MOx) in the water column acts as a biological filter, reducing the amount of methane that eventually evades to the atmosphere. The efficiency of the MOx filter is potentially controlled by the availability of dissolved methane and oxygen, as well as temperature, salinity, and hydrographic dynamics, and all of these factors undergo strong temporal fluctuations in coastal ecosystems. In order to elucidate the key environmental controls, specifically the effect of oxygen availability, on MOx in a seasonally stratified and hypoxic coastal marine setting, we conducted a 2-year time-series study with measurements of MOx and physicochemical water column parameters in a coastal inlet in the south-western Baltic Sea (Eckernförde Bay). We found that MOx rates generally increased toward the seafloor, but were not directly linked to methane concentrations. MOx exhibited a strong seasonal variability, with maximum rates (up to 11.6 nmol L−1 d −1 ) during summer stratification when oxygen concentrations were lowest and bottom-water temperatures were highest. Under these conditions, 2.4–19.0 times more methane was oxidized than emitted to the atmosphere, whereas about the same amount was consumed and emitted during the mixed and oxygenated periods. Laboratory experiments with manipulated oxygen concentrations in the range of 0.2–220 µmol L−1 revealed a submicromolar oxygen optimum for MOx at the study site. In contrast, the fraction of methane–carbon incorporation into the bacterial biomass (compared to the total amount of oxidized methane) was up to 38-fold higher at saturated oxygen concentrations, suggesting a different partitioning of catabolic and anabolic processes under oxygen-replete and oxygen-starved conditions, respectively. Our results underscore the importance of MOx in mitigating methane emission from coastal waters and indicate an organism-level adaptation of the water column methanotrophs to hypoxic conditions. Article in Journal/Newspaper Arctic University of Tromsø: Munin Open Research Archive Biogeosciences 14 6 1631 1645 |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 |
spellingShingle |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 Steinle, Lea Maltby, Johanna Treude, Tina Kock, Annette Bange, Hermann W. Engbersen, Nadine Zopfi, Jakob Lehmann, Moritz F. Niemann, Helge Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
topic_facet |
VDP::Matematikk og Naturvitenskap: 400::Geofag: 450::Marin geologi: 466 |
description |
Source at https://doi.org/10.5194/bg-14-1631-2017 . Coastal seas may account for more than 75 % of global oceanic methane emissions. There, methane is mainly produced microbially in anoxic sediments from which it can escape to the overlying water column. Aerobic methane oxidation (MOx) in the water column acts as a biological filter, reducing the amount of methane that eventually evades to the atmosphere. The efficiency of the MOx filter is potentially controlled by the availability of dissolved methane and oxygen, as well as temperature, salinity, and hydrographic dynamics, and all of these factors undergo strong temporal fluctuations in coastal ecosystems. In order to elucidate the key environmental controls, specifically the effect of oxygen availability, on MOx in a seasonally stratified and hypoxic coastal marine setting, we conducted a 2-year time-series study with measurements of MOx and physicochemical water column parameters in a coastal inlet in the south-western Baltic Sea (Eckernförde Bay). We found that MOx rates generally increased toward the seafloor, but were not directly linked to methane concentrations. MOx exhibited a strong seasonal variability, with maximum rates (up to 11.6 nmol L−1 d −1 ) during summer stratification when oxygen concentrations were lowest and bottom-water temperatures were highest. Under these conditions, 2.4–19.0 times more methane was oxidized than emitted to the atmosphere, whereas about the same amount was consumed and emitted during the mixed and oxygenated periods. Laboratory experiments with manipulated oxygen concentrations in the range of 0.2–220 µmol L−1 revealed a submicromolar oxygen optimum for MOx at the study site. In contrast, the fraction of methane–carbon incorporation into the bacterial biomass (compared to the total amount of oxidized methane) was up to 38-fold higher at saturated oxygen concentrations, suggesting a different partitioning of catabolic and anabolic processes under oxygen-replete and oxygen-starved conditions, respectively. Our results underscore the importance of MOx in mitigating methane emission from coastal waters and indicate an organism-level adaptation of the water column methanotrophs to hypoxic conditions. |
format |
Article in Journal/Newspaper |
author |
Steinle, Lea Maltby, Johanna Treude, Tina Kock, Annette Bange, Hermann W. Engbersen, Nadine Zopfi, Jakob Lehmann, Moritz F. Niemann, Helge |
author_facet |
Steinle, Lea Maltby, Johanna Treude, Tina Kock, Annette Bange, Hermann W. Engbersen, Nadine Zopfi, Jakob Lehmann, Moritz F. Niemann, Helge |
author_sort |
Steinle, Lea |
title |
Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
title_short |
Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
title_full |
Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
title_fullStr |
Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
title_full_unstemmed |
Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
title_sort |
effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters |
publisher |
European Geosciences Union (EGU) |
publishDate |
2017 |
url |
https://hdl.handle.net/10037/12618 https://doi.org/10.5194/bg-14-1631-2017 |
genre |
Arctic |
genre_facet |
Arctic |
op_relation |
Biogeosciences info:eu-repo/grantAgreement/RCN/SFF/223259/Norway/Centre for Arctic Gas Hydrate, Environment and Climate/CAGE/ Steinle, L., Maltby, J., Treude, T., Kock, A., Bange, H.W., Engbersen, N., … Niemann, H. (2017). Effects of low oxygen concentrations on aerobic methane oxidation in seasonally hypoxic coastal waters. Biogeosciences, 14:1631-1645. https://doi.org/10.5194/bg-14-1631-2017 FRIDAID 1464756 doi:10.5194/bg-14-1631-2017 1726-4170 1726-4189 https://hdl.handle.net/10037/12618 |
op_rights |
openAccess |
op_doi |
https://doi.org/10.5194/bg-14-1631-2017 |
container_title |
Biogeosciences |
container_volume |
14 |
container_issue |
6 |
container_start_page |
1631 |
op_container_end_page |
1645 |
_version_ |
1766300988158771200 |