DOI: 10.5194/hess-19-4505-2015
Scopus记录号: 2-s2.0-84946762276
论文题名: Quantitative analysis of biogeochemically controlled density stratification in an iron-meromictic lake
作者: Nixdorf E ; , Boehrer B
刊名: Hydrology and Earth System Sciences
ISSN: 10275606
出版年: 2015
卷: 19, 期: 11 起始页码: 4505
结束页码: 4515
语种: 英语
Scopus关键词: Electric conductivity
; Groundwater
; Iron
; Iron compounds
; Lakes
; Density stratification
; Electrical conductivity
; Organic materials
; Quantitative approach
; Quantitative variables
; Seasonal variation
; Underground mining
; Vertical transports
; Water aeration
; aeration
; anoxic conditions
; biogeochemical cycle
; concentration (composition)
; deep water
; electrical conductivity
; groundwater
; iron
; laboratory method
; lignite
; mining
; qualitative analysis
; reaction kinetics
; solute
; stratification
; visual analysis
英文摘要: Lake stratification controls the cycling of dissolved matter within the water body. This is of particular interest in the case of meromictic lakes, where permanent density stratification of the deep water limits vertical transport, and a chemically different (reducing) milieu can be established. As a consequence, the geochemical setting and the mixing regime of a lake can stabilize each other mutually. We attempt a quantitative approach to the contribution of chemical reactions sustaining the density stratification. As an example, we chose the prominent case of iron meromixis in Waldsee near Doebern, a small lake that originated from near-surface underground mining of lignite. From a data set covering 4 years of monthly measured electrical conductivity profiles, we calculated summed conductivity as a quantitative variable reflecting the amount of electro-active substances in the entire lake. Seasonal variations followed the changing of the chemocline height. Coinciding changes of electrical conductivities in the monimolimnion indicated that a considerable share of substances, precipitated by the advancing oxygenated epilimnion, re-dissolved in the remaining anoxic deep waters and contributed considerably to the density stratification. In addition, we designed a lab experiment, in which we removed iron compounds and organic material from monimolimnetic waters by introducing air bubbles. Precipitates could be identified by visual inspection. Eventually, the remaining solutes in the aerated water layer looked similar to mixolimnetic Waldsee water. Due to its reduced concentration of solutes, this water became less dense and remained floating on nearly unchanged monimolimnetic water. In conclusion, iron meromixis as seen in Waldsee did not require two different sources of incoming waters, but the inflow of iron-rich deep groundwater and the aeration through the lake surface were fully sufficient for the formation of iron meromixis. © Author(s) 2015. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/78387
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Environmental Informatics, Helmholtz Centre for Environmental Research, Leipzig, Germany; Department of Lake Research, Helmholtz Centre for Environmental Research, Magdeburg, Germany
Recommended Citation:
Nixdorf E,, Boehrer B. Quantitative analysis of biogeochemically controlled density stratification in an iron-meromictic lake[J]. Hydrology and Earth System Sciences,2015-01-01,19(11)