DOI: 10.1007/s10533-013-9944-z
Scopus记录号: 2-s2.0-84897435262
论文题名: Lack of steady-state in the global biogeochemical Si cycle: Emerging evidence from lake Si sequestration
作者: Frings P.J. ; Clymans W. ; Jeppesen E. ; Lauridsen T.L. ; Struyf E. ; Conley D.J.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2014
卷: 117, 期: 2018-02-03 起始页码: 255
结束页码: 277
语种: 英语
英文关键词: Biogenic silica
; Lake retention
; Silica cycle
; Silicon isotopes
Scopus关键词: biogeochemical cycle
; catchment
; chemical weathering
; geoaccumulation
; isotopic composition
; lake
; mass balance
; numerical model
; reservoir
; silicate
; silicon
; steady-state equilibrium
; surficial sediment
英文摘要: Weathering of silicate minerals releases dissolved silicate (DSi) to the soil-vegetation system. Accumulation and recycling of this DSi by terrestrial ecosystems creates a pool of reactive Si on the continents that buffers DSi export to the ocean. Human perturbations to the functioning of the buffer have been a recent research focus, yet a common assumption is that the continental Si cycle is at steady-state. However, we have no good idea of the timescales of ecosystem Si pool equilibration with their environments. A review of modelling and geochemical considerations suggests the modern continental Si cycle is in fact characterised in the long-term by an active accumulation of reactive Si, at least partially attributable to lakes and reservoirs. These lentic systems accumulate Si via biological conversion of DSi to biogenic silica (BSi). An analysis of new and published data for nearly 700 systems is presented to assess their contribution to the accumulating continental pool. Surface sediment BSi concentrations (n = 692) vary between zero and >60 % SiO2 by weight, apparently independently of lake size, location or water chemistry. Using sediment core BSi accumulation rates (n = 109), still no relationships are found with lake or catchment parameters. However, issues associated with single-core accumulation rates should in any case preclude their use in elemental accumulation calculations. Based on lake/reservoir mass-balances (n = 34), our best global-scale estimate of combined lake and reservoir Si retention is 1.53 TMol year-1, or 21-27 % of river DSi export. Again, no scalable relationships are apparent, suggesting Si retention is a complex process that varies from catchment to catchment. The lake Si sink has implications for estimation of weathering flux generation from river chemistry. The size of the total continental Si pool is poorly constrained, as is its accumulation rate, but lakes clearly contribute substantially. A corollary to this emerging understanding is that the flux and isotopic composition of DSi delivered to the ocean has likely varied over time, partly mediated by a fluctuating continental pool, including in lakes. © 2014 Springer Science+Business Media Dordrecht. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83587
Appears in Collections: 气候减缓与适应 气候变化事实与影响
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作者单位: Department of Geology, Lund University, Sölvegaten 12, 22362 Lund, Sweden; Department of Bioscience, Freshwater Ecology, Vejlsøvej 25, 8600 Silkeborg, Denmark; Department of Biology, Research Group Ecosystem Management, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium
Recommended Citation:
Frings P.J.,Clymans W.,Jeppesen E.,et al. Lack of steady-state in the global biogeochemical Si cycle: Emerging evidence from lake Si sequestration[J]. Biogeochemistry,2014-01-01,117(2018-02-03)