气候变化领域集成服务门户(CCPortal): Methane concentrations in the central North Sea

CCPortal

DOI	https://doi.org/10.1594/PANGAEA.854990
	Methane concentrations in the central North Sea
	Mau; Susan; Gentz; Torben; Körber; Jan-Hendrik; Torres; Marta E; Römer; Miriam; Sahling; Heiko; Wintersteller; Paul; Martinez; Roi; Schlüter; Michael; Helmke; Elisabeth
发布日期	2015-11-16
数据集类型	dataset
英文简介	We investigated dissolved methane distributions along a 6 km transect crossing active seep sites at 40 m water depth in the central North Sea. These investigations were done under conditions of thermal stratification in summer (July 2013) and homogenous water column in winter (January 2014). Dissolved methane accumulated below the seasonal thermocline in summer with a median concentration of 390 nM, whereas during winter, methane concentrations were typically much lower (median concentration of 22 nM). High-resolution methane analysis using an underwater mass-spectrometer confirmed our summer results and was used to document prevailing stratification over the tidal cycle. We contrast estimates of methane oxidation rates (from 0.1 to 4.0 nM day-1) using the traditional approach scaled to methane concentrations with microbial turnover time values and suggest that the scaling to concentration may obscure the ecosystem microbial activity when comparing systems with different methane concentrations. Our measured and averaged rate constants (k') were on the order of 0.01 day-1, equivalent to a turnover time of 100 days, even when summer stratification led to enhanced methane concentrations in the bottom water. Consistent with these observations, we could not detect known methanotrophs and pmoA genes in water samples collected during both seasons. Estimated methane fluxes indicate that horizontal transport is the dominant process dispersing the methane plume. During periods of high wind speed (winter), more methane is lost to the atmosphere than oxidized in the water. Microbial oxidation seems of minor importance throughout the year.
空间范围	Median Latitude: 55.305804 * Median Longitude: 4.078249 * South-bound Latitude: 55.305000 * West-bound Longitude: 4.041500 * North-bound Latitude: 55.306170 * East-bound Longitude: 4.138830
时间范围	2013-07-22T11:03:00 - 2014-01-17T12:10:00
语种	英语
国家	国际
学科大类	气候变化
学科子类	气候变化
文献类型	数据集
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/215430
推荐引用方式 GB/T 7714	Mau,Susan,Gentz,et al. Methane concentrations in the central North Sea.2015-11-16.https://doi.org/10.1594/PANGAEA.854990.