Shallow gas in the muddy sediments of Eckernförde Bay, Germany

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	Shallow gas in the muddy sediments of Eckernförde Bay, Germany
	Th. F. Wever ; F. Abeggb ; H. M. Fiedlera ; G. Fechnera and I. H. Stender
发表期刊	Continental Shelf Research
ISSN	0278-4343
	1998
卷号	18 期号:14-15 页码:1715-1739
通讯作者	Th. F. Wever
英文摘要	The seafloor of central Eckernförde Bay is characterised by soft muddy sediments that contain free methane gas. Bubbles of free gas cause acoustic turbidity which is observed with acoustic remote sensing systems. Repeated surveys with subbottom profiler and side scan sonar revealed an annual period both of depth of the acoustic turbidity and backscatter strength. The effects are delayed by 3–4 months relative to the atmospheric temperature cycle. In addition, prominent pockmarks, partly related to gas seepage, were detected with the acoustic systems. In a direct approach gas concentrations were measured from cores using the gas chromatography technique. From different tests it is concluded that subsampling of a core should start at its base and should be completed as soon as possible, at least within 35 min after core recovery. Comparison of methane concentrations of summer and winter cores revealed no significant seasonal variation. Thus, it is concluded that the temperature and pressure influences upon solubility control the depth variability of acoustic turbidity which is observed with acoustic remote sensing systems. The delay relative to the atmospheric temperature cycle is caused by slow heat transfer through the water column. The atmospheric temperature cycle as ‘exiting function’ for variable gas solubility offers an opportunity for modelling and predicting the depth of the acoustic turbidity. In practice, however, small-scale variations of, e.g., salinity, or gas concentration profile in the sediment impose limits to predictions. In addition, oceanographic influences as mixing in the water column, variable water inflow, etc. are further complications that reduce the reliability of predictions.
语种	英语
文献类型	期刊论文
条目标识符	http://ir.yic.ac.cn/handle/133337/3083
专题	科研共享资源
推荐引用方式 GB/T 7714	Th. F. Wever,F. Abeggb,H. M. Fiedlera,et al. Shallow gas in the muddy sediments of Eckernförde Bay, Germany[J]. Continental Shelf Research,1998,18(14-15):1715-1739.
APA	Th. F. Wever,F. Abeggb,H. M. Fiedlera,&G. Fechnera and I. H. Stender.(1998).Shallow gas in the muddy sediments of Eckernförde Bay, Germany.Continental Shelf Research,18(14-15),1715-1739.
MLA	Th. F. Wever,et al."Shallow gas in the muddy sediments of Eckernförde Bay, Germany".Continental Shelf Research 18.14-15(1998):1715-1739.

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