DOI: 10.1002/2013GB004670
Scopus记录号: 2-s2.0-84896588210
论文题名: The fate of terrigenous dissolved organic carbon in a river-influenced ocean margin
作者: Fichot C ; G ; , Benner R
刊名: Global Biogeochemical Cycles
ISSN: 8866236
出版年: 2014
卷: 28, 期: 3 起始页码: 300
结束页码: 318
语种: 英语
英文关键词: biomineralization
; decay constant
; mass balance
; ocean margin
; photomineralization
; terrigenous dissolved organic carbon
Scopus关键词: Biomineralization
; Carbon dioxide
; Ecology
; Oceanography
; Rivers
; Stream flow
; Decay constants
; Dissolved organic carbon
; Mass balance
; ocean margin
; Photomineralization
; Mineralogy
; air-sea interaction
; biogeochemical cycle
; biomineralization
; carbon dioxide
; chemical mass balance
; continental margin
; dissolved organic carbon
; estuarine front
; lignin
; mixed layer
; photochemistry
; river discharge
; river system
; seasonality
; source-sink dynamics
; terrigenous deposit
; transformation
; Atchafalaya River
; Atlantic Ocean
; Gulf of Mexico
; Louisiana
; Louisiana Shelf
; Mississippi River
; United States
英文摘要: The mineralization of terrigenous dissolved organic carbon (tDOC) discharged by rivers can impact nutrient and trace metal cycling, biological productivity, net ecosystem metabolism, and air-sea CO2 exchange in ocean margins. However, the extreme heterogeneity of river-influenced ocean margins represents a major challenge for quantitative assessments of tDOC transformations and thereby obscures the role of tDOC in biogeochemical cycles. Here a lignin-based optical proxy for tDOC and a shelf-wide mass balance approach were used to quantitatively assess the fate of tDOC discharged from the Mississippi-Atchafalaya River System (M-ARS) to the Louisiana shelf. The mass balance revealed that ∼40% of the tDOC discharged by the M-ARS during March 2009-2010 was mineralized to CO2 on the Louisiana shelf, with two thirds of the mineralization taking place in the mixed layer. A strong seasonality in tDOC mineralization was observed, with mineralization rates severalfold higher during summer than during winter. Independent assessments of specific mineralization processes indicated biomineralization accounted for ∼94% of the tDOC mineralization on an annual basis and suggest that photochemical transformations of tDOC enhanced biomineralization by ∼50% in the mixed layer. Direct photomineralization accounted for a relatively small fraction (∼6%) of the tDOC mineralization on an annual basis. This quantitative assessment directly confirms that ocean margins are major sinks of the tDOC discharged by rivers and indicates that tDOC mineralization rates in the shelf mixed layer are sufficiently large to influence whether the Louisiana shelf is a net sink or source of atmospheric CO2. ©2014. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/77510
Appears in Collections: 气候变化事实与影响
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作者单位: Marine Science Program, University of South Carolina, Columbia, SC, United States; Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
Recommended Citation:
Fichot C,G,, Benner R. The fate of terrigenous dissolved organic carbon in a river-influenced ocean margin[J]. Global Biogeochemical Cycles,2014-01-01,28(3)