CH4 oxidation in a boreal lake during the development of hypolimnetic hypoxia

Show full item record



Permalink

http://hdl.handle.net/10138/312089

Citation

Saarela , T , Rissanen , A J , Ojala , A , Pumpanen , J , Aalto , S L , Tiirola , M , Vesala , T & Jantti , H 2020 , ' CH4 oxidation in a boreal lake during the development of hypolimnetic hypoxia ' , Aquatic Sciences , vol. 82 , no. 2 , 19 . https://doi.org/10.1007/s00027-019-0690-8

Title: CH4 oxidation in a boreal lake during the development of hypolimnetic hypoxia
Author: Saarela, Taija; Rissanen, Antti J.; Ojala, Anne; Pumpanen, Jukka; Aalto, Sanni L.; Tiirola, Marja; Vesala, Timo; Jantti, Helena
Contributor: University of Helsinki, Ecosystems and Environment Research Programme
University of Helsinki, University of Eastern Finland
University of Helsinki, University of Eastern Finland
University of Helsinki, Institute for Atmospheric and Earth System Research (INAR)
University of Helsinki, University of Eastern Finland
Date: 2020-04
Language: eng
Number of pages: 12
Belongs to series: Aquatic Sciences
ISSN: 1015-1621
URI: http://hdl.handle.net/10138/312089
Abstract: Freshwater ecosystems represent a significant natural source of methane (CH4). CH4 produced through anaerobic decomposition of organic matter (OM) in lake sediment and water column can be either oxidized to carbon dioxide (CO2) by methanotrophic microbes or emitted to the atmosphere. While the role of CH4 oxidation as a CH4 sink is widely accepted, neither the magnitude nor the drivers behind CH4 oxidation are well constrained. In this study, we aimed to gain more specific insight into CH4 oxidation in the water column of a seasonally stratified, typical boreal lake, particularly under hypoxic conditions. We used (CH4)-C-13 incubations to determine the active CH4 oxidation sites and the potential CH4 oxidation rates in the water column, and we measured environmental variables that could explain CH4 oxidation in the water column. During hypolimnetic hypoxia, 91% of available CH4 was oxidized in the active CH4 oxidation zone, where the potential CH4 oxidation rates gradually increased from the oxycline to the hypolimnion. Our results showed that in warm springs, which become more frequent, early thermal stratification with cold well-oxygenated hypolimnion delays the period of hypolimnetic hypoxia and limits CH4 production. Thus, the delayed development of hypolimnetic hypoxia may partially counteract the expected increase in the lacustrine CH4 emissions caused by the increasing organic carbon load from forested catchments.
Subject: Boreal lake
Greenhouse gases
Hypoxia
Methane
Oxidation
Stable isotopes
Stratification
ANAEROBIC METHANE OXIDATION
ORGANIC-CARBON
WATER COLUMN
CO2 CONCENTRATION
DYNAMICS
SUMMER
STRATIFICATION
SEDIMENTS
CLIMATE
FLUXES
1172 Environmental sciences
119 Other natural sciences
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
Saarela2019_Art ... tionInABorealLakeDurin.pdf 1.097Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record