DOI: 10.1016/j.epsl.2018.05.029
Scopus记录号: 2-s2.0-85047651559
论文题名: Nucleation and growth of Mg-bearing calcite in a shallow, calcareous lake
作者: Nyirő-Kósa I. ; Rostási Á. ; Bereczk-Tompa É. ; Cora I. ; Koblar M. ; Kovács A. ; Pósfai M.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 496 起始页码: 20
结束页码: 28
语种: 英语
英文关键词: crystal size and shape control
; Lake Balaton
; Mg-bearing calcite
; smectite
; templated nucleation
Scopus关键词: Bioactivity
; Calcite
; Nucleation
; Particle size
; Precipitation (chemical)
; Sediments
; Single crystals
; X ray powder diffraction
; Calcite precipitation
; Crystal size and shape
; Crystallographic directions
; Lake Balaton
; Nucleation and growth
; Smectites
; Spatial relationships
; Templated
; Lakes
; calcite
; carbonate group
; chemical composition
; crystal
; lake water
; nucleation
; precipitation (chemistry)
; shallow water
; smectite
; water chemistry
; water temperature
; Hungary
; Lake Balaton
英文摘要: Both inorganic and microbial processes play important roles in carbonate mineral precipitation in freshwater lakes. Identifying the individual factors that determine particle size, shape, composition, and the spatial relationships of carbonates with other constituents of the sediment are important for understanding sediment formation and nutrient cycling, and for providing input for lake management planning. We studied the formation of Mg-bearing calcite in Lake Balaton, a large, shallow, Mg-rich, calcareous lake in Hungary, by filtering particles from the water and analyzing them using X-ray powder diffraction and electron microscopy techniques. Mg-bearing calcite particles from Lake Balaton have distinct and remarkably consistent morphologies, independent of seasonal and annual variations in water temperature and composition. They are typically elongated parallel to the [001] crystallographic direction, are about 4 to 8 μm long, and even though appear to be composed of many smaller units, electron diffraction patterns indicate they are perfect single crystals. The Mg content of calcite increases from west to east, reflecting a gradient in lakewater composition. The calcite crystals are invariably attached to nm-scale flakes of smectite, suggesting that the clay mineral serves as a nucleation site. The templated nucleation may direct the growth of calcite parallel to the clay flakes, resulting in its elongated shape and single crystalline character. While in deep, oligotrophic lakes calcite typically nucleates on picoplankton cells, we rarely observe this phenomenon in Lake Balaton. Because of the shallowness of the lake, sediments are stirred up by even moderate winds and the movement of organisms, making nm-scale smectite flakes readily available for templating calcite nucleation. Thus, while calcite precipitation is an indirect consequence of biological activity (photosynthesis), the physical properties of the particles are primarily determined by inorganic factors. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109798
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Department of Earth and Environmental Sciences, University of Pannonia, Veszprém, H8200, Hungary; Institute of Technical Physics and Materials Science, Centre for Energy Research, Budapest, H1122, Hungary; Jožef Stefan Institute, Ljubljana, 1000, Slovenia; Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Peter Grünberg Institute, Forschungszentrum Jülich, Jülich, 52428, Germany
Recommended Citation:
Nyirő-Kósa I.,Rostási Á.,Bereczk-Tompa É.,et al. Nucleation and growth of Mg-bearing calcite in a shallow, calcareous lake[J]. Earth and Planetary Science Letters,2018-01-01,496