气候变化领域集成服务门户(CCPortal): Biogeochemical and physical controls on methane fluxes from two ferruginous meromictic lakes

CCPortal

DOI	10.1111/gbi.12365
	Biogeochemical and physical controls on methane fluxes from two ferruginous meromictic lakes
	Lambrecht N.; Katsev S.; Wittkop C.; Hall S.J.; Sheik C.S.; Picard A.; Fakhraee M.; Swanner E.D.
发表日期	2020
ISSN	14724677
起始页码	54
结束页码	69
卷号	18 期号:1
英文摘要	Meromictic lakes with anoxic bottom waters often have active methane cycles whereby methane is generally produced biogenically under anoxic conditions and oxidized in oxic surface waters prior to reaching the atmosphere. Lakes that contain dissolved ferrous iron in their deep waters (i.e., ferruginous) are rare, but valuable, as geochemical analogues of the conditions that dominated the Earth's oceans during the Precambrian when interactions between the iron and methane cycles could have shaped the greenhouse regulation of the planet's climate. Here, we explored controls on the methane fluxes from Brownie Lake and Canyon Lake, two ferruginous meromictic lakes that contain similar concentrations (max. >1 mM) of dissolved methane in their bottom waters. The order Methanobacteriales was the dominant methanogen detected in both lakes. At Brownie Lake, methanogen abundance, an increase in methane concentration with respect to depths closer to the sediment, and isotopic data suggest methanogenesis is an active process in the anoxic water column. At Canyon Lake, methanogenesis occurred primarily in the sediment. The most abundant aerobic methane-oxidizing bacteria present in both water columns were associated with the Gammaproteobacteria, with little evidence of anaerobic methane oxidizing organisms being present or active. Direct measurements at the surface revealed a methane flux from Brownie Lake that was two orders of magnitude greater than the flux from Canyon Lake. Comparison of measured versus calculated turbulent diffusive fluxes indicates that most of the methane flux at Brownie Lake was non-diffusive. Although the turbulent diffusive methane flux at Canyon Lake was attenuated by methane oxidizing bacteria, dissolved methane was detected in the epilimnion, suggestive of lateral transport of methane from littoral sediments. These results highlight the importance of direct measurements in estimating the total methane flux from water columns, and that non-diffusive transport of methane may be important to consider from other ferruginous systems. © 2019 John Wiley & Sons Ltd
关键词	anoxic conditions atmosphere-hydrosphere interaction bacterium biogeochemical cycle bottom water concentration (composition)detection method flux measurement geochemistry meromictic lake methane methanogenesis methanogenic bacterium Precambrian Lake Ransom Canyon Texas United States Gammaproteobacteria Methanobacteriales Scomberomorus semifasciatus iron methane atmosphere lake oxidation reduction reaction Atmosphere Iron Lakes Methane Oxidation-Reduction
语种	英语
来源机构	Geobiology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/133208
推荐引用方式 GB/T 7714	Lambrecht N.,Katsev S.,Wittkop C.,et al. Biogeochemical and physical controls on methane fluxes from two ferruginous meromictic lakes[J]. Geobiology,2020,18(1).
APA	Lambrecht N..,Katsev S..,Wittkop C..,Hall S.J..,Sheik C.S..,...&Swanner E.D..(2020).Biogeochemical and physical controls on methane fluxes from two ferruginous meromictic lakes.,18(1).
MLA	Lambrecht N.,et al."Biogeochemical and physical controls on methane fluxes from two ferruginous meromictic lakes".18.1(2020).