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S. Schwarzenbach

Bio: S. Schwarzenbach is an academic researcher from Swiss Federal Institute of Aquatic Science and Technology. The author has contributed to research in topics: Greenhouse gas & Methane. The author has an hindex of 2, co-authored 3 publications receiving 62 citations.

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TL;DR: In this paper, the first results of greenhouse gas emissions from reservoirs at high elevations in the Alps were investigated, and the results indicate reservoirs from subalpine/alpine regions to be only minor contributors of greenhouse gases to the atmosphere compared to other reservoirs.
Abstract: We investigated greenhouse gas emissions (CO2, CH4, and N2O) from reservoirs located across an altitude gradient in Switzerland. These are the first results of greenhouse gas emissions from reservoirs at high elevations in the Alps. Depth profiles were taken in 11 reservoirs located at different altitudes between the years 2003 and 2006. Diffusive trace gas emissions were calculated using surface gas concentrations, wind speeds and transfer velocities. Additionally, methane entering with the inflowing water and methane loss at the turbine was assessed for a subset of the reservoirs. All reservoirs were emitters of carbon dioxide and methane with an average of 970 ± 340 mg m−2 day−1 (results only from four lowland and one subalpine reservoir) and 0.20 ± 0.15 mg m−2 day−1, respectively. One reservoir (Lake Wohlen) emitted methane at a much higher rate (1.8 ± 0.9 mg m−2 day−1) than the other investigated reservoirs. There was no significant difference in methane emissions across the altitude gradient, but average dissolved methane concentrations decreased with increasing elevation. Only lowland reservoirs were sources for N2O (72 ± 22 μg m−2 day−1), while the subalpine and alpine reservoirs were in equilibrium with atmospheric concentrations. These results indicate reservoirs from subalpine/alpine regions to be only minor contributors of greenhouse gases to the atmosphere compared to other reservoirs.

66 citations

Posted ContentDOI
TL;DR: In this paper, the authors measured greenhouse gas (CO2, CH4, and N2O) emissions from eleven reservoirs located at different altitudes in Switzerland depth profiles of greenhouse gas concentrations were measured several times during spring and summer.
Abstract: . In eleven reservoirs located at different altitudes in Switzerland depth profiles of greenhouse gas (CO2, CH4, and N2O) concentrations were measured several times during spring and summer. Trace gas emissions were calculated using surface concentrations, wind speeds and transfer velocities. Additionally we assessed methane loss at the turbine and the methane input by inflowing water. All reservoirs were net emitters of CO2 with an average of 1030±780 mg m−2 d−1 and of methane with an average of 0.20±0.15 mg m−2 d−1. One reservoir (Lake Wohlen) emitted methane at a much higher rate (160±110 mg m−2 d−1), most of which (>98%) was due to ebullition. Only lowland reservoirs were sources for N2O (72±22 μg m−2 d−1), while the subalpine and alpine reservoirs seem to be in equilibrium with atmospheric concentrations. Methane loss at the turbine was as large as the diffusive flux from the surface for two subalpine reservoirs and around five times smaller for a lowland reservoir. The available data suggests greenhouse gas emissions from reservoirs in the Alps are minor contributors to the global greenhouse gas emissions.

6 citations


Cited by
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Journal ArticleDOI
Pete Falloon1, Richard Betts1
TL;DR: The importance of interactions and feedbacks in assessing climate change impacts on water and agriculture in Europe is reviewed and qualitatively assessed, particularly on the impact of future hydrological changes on agricultural greenhouse gas mitigation and adaptation options.

387 citations

Journal ArticleDOI
TL;DR: Although fluxes were high, on average 4 mmol m(-2) d(-1) during the overturn period, water column microbial methane oxidation removed 75% of the methane and only 25% of potential emissions were released to the atmosphere, illustrating the importance of considering methane oxidation when estimating the flux of methane from lakes during overturn periods.
Abstract: Lakes are large sources of methane, held to be responsible for 18% of the radiative forcing, to the atmosphere. Periods of lake overturn (during fall/winter) are short and therefore difficult to capture with field campaigns but potentially one of the most important periods for methane emissions. We studied methane emissions using four different methods, including eddy covariance measurements, floating chambers, anchored funnels, and boundary model calculations. Whereas the first three methods agreed rather well, boundary model estimates were 5–30 times lower leading to a strong underestimation of methane fluxes from aquatic systems. These results show the importance of ebullition as the most important flux pathway and the need for continuous measurements with a large footprint covering also shallow parts of lakes. Although fluxes were high, on average 4 mmol m–2 d–1 during the overturn period, water column microbial methane oxidation removed 75% of the methane and only 25% of potential emissions were rele...

138 citations

Journal ArticleDOI
TL;DR: The build-up of methane in the hypolimnion of the eutrophic Lake Rotsee (Lucerne, Switzerland) was monitored over a full year as mentioned in this paper.
Abstract: The build-up of methane in the hypolimnion of the eutrophic Lake Rotsee (Lucerne, Switzerland) was monitored over a full year. Sources and sinks of methane in the water column were characterized by measuring concentrations and carbon isotopic composition. In fall, high methane concentrations (up to 1 mM) were measured in the anoxic water layer. In the oxic layer, methane concentrations were much lower and the isotopic composition shifted towards heavy carbon isotopes. Methane oxidation rates peaked at the interface between oxic and anoxic water layers at around 8–10 m depth. The electron balance between the oxidants oxygen, sulphate, and nitrate, and the reductants methane, sulphide and ammonium, matched very well in the chemocline during the stratified season. The profile of carbon isotopic composition of methane showed strong indications for methane oxidation at the chemocline (including the oxycline). Aerobic methane oxidizing bacteria were detected at the interface using fluorescence in situ hybridization. Sequencing the responsible organisms from DGGE bands revealed that aerobic methanotrophs type I closely related to Methylomonas were present. Sulphate consumption occurred at the sediment surface and, only towards the end of the stagnation period, matched with a zone of methane consumption. In any case, the flux of sulphate below the chemocline was not sufficient to oxidize all the methane and other oxidants like nitrate, iron or manganese are necessary for the observed methane oxidation. Although most of the methane was oxidized either aerobically or anaerobically, Lake Rotsee was still a source of methane to the atmosphere with emission rates between 0.2 mg CH4 m−2 day−1 in February and 7 mg CH4 m−2 day−1 in November.

116 citations

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TL;DR: In this article, measurements of nitrous oxide concentrations from 321 rivers, lakes, and ponds in Canada reveal that some boreal aquatic systems can act as net nitrous dioxide sinks.
Abstract: Aquatic ecosystems are important sources of the greenhouse gas nitrous oxide. Measurements of nitrous oxide concentrations from 321 rivers, lakes and ponds in Canada reveal that some boreal aquatic systems can act as net nitrous oxide sinks.

105 citations

Journal ArticleDOI
TL;DR: This study investigated the magnitude of carbon dioxide, methane and nitrous oxide fluxes from two coastal aquaculture ponds during 2011 and 2012 in the Shanyutan wetland of the Min River estuary, southeastern China, and determined the factors that may regulate GHG fluxes.

61 citations