A novel sediment gas sampler and a subsurface gas collector used for measurement of the ebullition of methane and carbon dioxide from a eutrophied lake

• Published in: Science of the total environment Vol. 266; no. 1; pp. 153 - 158
• Main Authors: Huttunen, Jari T., Lappalainen, K.Matti, Saarijärvi, Erkki, Väisänen, Tero, Martikainen, Pertti J.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Shannon Elsevier B.V 05-02-2001; Elsevier Science
• Subjects: Carbon dioxide; Carbon Dioxide - analysis; Earth sciences; Earth, ocean, space; Ebullition; Environmental Monitoring - instrumentation; Exact sciences and technology; Gases - analysis; Geochemistry; Geologic Sediments - chemistry; Hydrology; Hydrology. Hydrogeology; Methane; Methane - analysis; Mineralogy; Sediment; Sediment bubble gas sampler; Silicates; Subsurface bubble gas collector; Water geochemistry; Water Movements; Scandinavia; Finland; Methane; Sediment; Ebullition; Sediment bubble gas sampler; Subsurface bubble gas collector; Carbon dioxide; carbon dioxide; lake sediments; boiling; eutrophication; lacustrine environment; Europe; methane; gaseous phase; sediment-water interface; lakes
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/S0048-9697(00)00749-X

A novel sediment bubble gas sampler and a subsurface bubble gas collector were designed to measure the ebullition of gases from profundal sediments of aquatic ecosystems. The sediment gas sampler was constructed to collect bubble gas samples directly from the uppermost sediment layers for gas composition analysis. The floating subsurface gas collector, designed to trap the bubbles released naturally from sediments, permitted the measurement of both the volume and the composition of the bubble gas. Due to its low cost, light weight and rapid sampling capability, the gas collector is ideal for studies requiring many replicate collectors. These devices were used for measurement of the ebullition of methane (CH
4) and carbon dioxide (CO
2) during an open water period from hypereutrophic Lake Postilampi, situated within the midboreal zone in Finland. The bubble gas obtained from the sediment with the sediment gas sampler had higher concentrations of CH
4 and CO
2 than the bubbles trapped in the gas collectors. This indicated that the bubble gas composition changed, either naturally during the migration of the bubbles from the sediment through the water column to the gas collectors, and/or during their storage in the collectors prior to sampling. The mean CH
4 ebullition from Lake Postilampi was estimated to be in the range from 36 to 46 mg m
−2 d
−1, based on the bubble gas CH
4 concentrations measured from the gas collectors and sediment, respectively. The bubbles contained only 0.02–0.57% of CO
2 and thus, the ebullition had no significance in the release of CO
2 from the lake.