DOI: 10.1016/j.quascirev.2012.12.005
Scopus记录号: 2-s2.0-84881377384
论文题名: Stable-isotope (H, O, and Si) evidence for seasonal variations in hydrology and Si cycling from modern waters in the Nile Basin: Implications for interpreting the quaternary record
作者: Cockerton H.E. ; Street-Perrott F.A. ; Leng M.J. ; Barker P.A. ; Horstwood M.S.A. ; Pashley V.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2013
卷: 66 起始页码: 4
结束页码: 21
语种: 英语
英文关键词: Diatoms
; Hydrological cycle
; Oxygen isotopes
; Palaeoclimatology
; Silicon cycle
; Silicon isotopes
Scopus关键词: Diatoms
; Hydrological cycles
; Oxygen isotopes
; Palaeoclimatology
; Silicon cycle
; Silicon isotopes
; Drought
; Isotopes
; Phytoplankton
; Surface waters
; Water management
; Water supply
; Silicon
; anthropogenic effect
; bioaccumulation
; concentration (composition)
; diatom
; evapotranspiration
; freshwater ecosystem
; glacial-interglacial cycle
; humidity
; hydrological cycle
; lacustrine deposit
; macrophyte
; paleoclimate
; paleohydrology
; Quaternary
; seasonal variation
; silicon
; stable isotope
; Nile Basin
; Bacillariophyta
英文摘要: Seasonal variations in hydrology and Si cycling in the Nile Basin were investigated using stable-isotope (H, O, and Si) compositions and dissolved Si (DSi) concentrations of surface waters, as a basis for interpreting lacustrine diatom sequences. δ18O ranged from 4.7 to 8.0& in the wet season and 0.6 to 8.8& in the dry season (through 2009-2011). Higher δ18O values during the dry season reflected increased evapotranspiration and open water evaporation under conditions of lower humidity. Progressive downstream enrichment in the heavy isotope 18O also occurred in response to cumulative evaporative losses from open water bodies and swamps. δ30Si values of DSi ranged from 0.48 to 3.45& during the wet season and 1.54 to 4.66& during the dry season, increasing the previously reported global upper limit for δ30Si values in natural waters by 1&. Si-isotope fractionation was most intense during the dry season when demand for DSi by aquatic ecosystems exceeded supply. Progressive downstream enrichment in the heavy isotope 30Si, coupled with decreasing DSi concentrations, represented cumulative Si uptake by diatoms, macrophytes and other Si-accumulating aquatic organisms. The pronounced seasonal variations in DSi concentrations and Si-isotope compositions in the River Nile suggest that its DSi flux to the ocean may have varied significantly on a glacial/interglacial time scale, with important consequences for the marine Si budget and consequently the global C cycle. Anthropogenic impacts were evident in both the water- and Si-isotope datasets, especially during the dry season and along the Main Nile, where water management is most intensive. © 2012 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60723
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geography, College of Science, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom; Department of Geology, University of Leicester, Leicester LE1 7RH, United Kingdom; NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom; Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, United Kingdom
Recommended Citation:
Cockerton H.E.,Street-Perrott F.A.,Leng M.J.,et al. Stable-isotope (H, O, and Si) evidence for seasonal variations in hydrology and Si cycling from modern waters in the Nile Basin: Implications for interpreting the quaternary record[J]. Quaternary Science Reviews,2013-01-01,66