DOI: 10.1007/s10533-016-0279-4
Scopus记录号: 2-s2.0-84997764831
论文题名: Seasonal and spatial variability of dissolved organic matter composition in the lower Amazon River
作者: Seidel M. ; Dittmar T. ; Ward N.D. ; Krusche A.V. ; Richey J.E. ; Yager P.L. ; Medeiros P.M.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2016
卷: 131, 期: 3 起始页码: 281
结束页码: 302
语种: 英语
英文关键词: Amazon River
; Dissolved organic matter
; Ultra-high resolution mass spectrometry
Scopus关键词: biogenic material
; dissolved organic carbon
; dissolved organic matter
; floodplain
; hydrology
; lacustrine environment
; mass spectrometry
; seasonality
; spatial variation
; Amazon River
; algae
; Embryophyta
英文摘要: We analyzed the molecular composition of dissolved organic matter (DOM) in the lower Amazon River (ca. 850 km from Óbidos to the mouth) using ultrahigh-resolution mass spectrometry and geochemical tracers. Changes in DOM composition along this lower reach suggest a transition from higher plant-derived DOM to more algal/microbial-derived DOM. This result was likely due to a combination of autochthonous production, alteration of terrigenous DOM as it transits down the river, and increased algal inputs from floodplain lakes and clearwater tributaries during high discharge conditions. Spatial gradients in dissolved organic carbon (DOC) concentrations varied with discharge. Maximal DOC concentrations were observed near the mouth during high water, highlighting the importance of lateral inputs of DOM along the lower river. The majority of DOM molecular formulae did not change within the time it takes the water in the mainstem to be transported through the lower reach. This is indicative of molecules representing a mixture of compounds that are resistant to rapid alteration and reactive compounds that are continuously replenished by the lateral input of terrestrial organic matter from the landscape, tributaries, and floodplains. River water incubations revealed that photo- and bio-transformation alter at most 30% of the DOM molecular formulae. River discharge at the mouth differed from the sum of discharge measurements made at Óbidos and the main gauged tributaries in the lower Amazon. This indicates that changes in hydrology and associated variations in the source waters along the lower reach affected the molecular composition of the DOM that is being transported from the Amazon River to the coastal ocean. © 2016, Springer International Publishing Switzerland. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83325
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 Marine Sciences, University of Georgia, Athens, GA, United States; Research Group for Marine Geochemistry (ICBM-MPI Bridging Group), Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany; School of Oceanography, University of Washington, Seattle, WA, United States; Centro de Energia Nuclear na Agricultura, Universidade de São Paulo, Piracicaba, SP, Brazil; Department of Geological Sciences, University of Florida, Gainesville, FL, United States
Recommended Citation:
Seidel M.,Dittmar T.,Ward N.D.,et al. Seasonal and spatial variability of dissolved organic matter composition in the lower Amazon River[J]. Biogeochemistry,2016-01-01,131(3)