DOI: 10.1111/gcb.12287
论文题名: Drought-induced saltwater incursion leads to increased wetland nitrogen export
作者: Ardón M. ; Morse J.L. ; Colman B.P. ; Bernhardt E.S.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2013
卷: 19, 期: 10 起始页码: 2976
结束页码: 2985
语种: 英语
英文关键词: Cation exchange
; Eutrophication
; Land-use change
; Salinization
; Sea-level rise
Scopus关键词: coastal water
; coastal wetland
; drought
; eutrophication
; ion exchange
; land use change
; nitrogen
; nitrogen cycle
; saline intrusion
; salinization
; sea level change
; soil column
; Mississippi River
; North Carolina
; United States
; ammonium derivative
; chloride
; nitrate
; nitrogen
; sea water
; sulfate
; article
; cation exchange
; drought
; eutrophication
; land-use change
; salinization
; sea-level rise
; United States
; water flow
; wetland
; cation exchange
; eutrophication
; land-use change
; salinization
; sea-level rise
; Ammonium Compounds
; Chlorides
; Droughts
; Nitrates
; Nitrogen
; North Carolina
; Seawater
; Sulfates
; Water Movements
; Wetlands
英文摘要: Coastal wetlands have the capacity to retain and denitrify large quantities of reactive nitrogen (N), making them important in attenuating increased anthropogenic N flux to coastal ecosystems. The ability of coastal wetlands to retain and transform N is being reduced by wetland losses resulting from land development. Nitrogen retention in coastal wetlands is further threatened by the increasing frequency and spatial extent of saltwater inundation in historically freshwater ecosystems, due to the combined effects of dredging, declining river discharge to coastal areas due to human water use, increased drought frequency, and accelerating sea-level rise. Because saltwater incursion may affect N cycling through multiple mechanisms, the impacts of salinization on coastal freshwater wetland N retention and transformation are not well understood. Here, we show that repeated annual saltwater incursion during late summer droughts in the coastal plain of North Carolina changed N export from organic to inorganic forms and led to a doubling of annual NH4+ export from a 440 hectare former agricultural field undergoing wetland restoration. Soil solution NH4+ concentrations in two mature wetlands also increased with salinization, but the magnitude of increase was smaller than that in the former agricultural field. Long-term saltwater exposure experiments with intact soil columns demonstrated that much of the increase in reactive N released could be explained by exchange of salt cations with sediment NH4+. Using these findings together with the predicted flooding of 1661 km2 of wetlands along the NC coast by 2100, we estimate that saltwater incursion into these coastal areas could release up to 18 077 Mg N, or approximately half the annual NH4+ flux of the Mississippi River. Our results suggest that saltwater incursion into coastal freshwater wetlands globally could lead to increased N loading to sensitive coastal waters. © 2013 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62317
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Biology and North Carolina Center for Biodiversity, East Carolina University, Greenville, NC, 27858, United States; Cary Institute of Ecosystem Studies, Millbrook, NY, 12545, United States; Department of Biology, Duke University, Durham, NC, 27708, United States
Recommended Citation:
Ardón M.,Morse J.L.,Colman B.P.,et al. Drought-induced saltwater incursion leads to increased wetland nitrogen export[J]. Global Change Biology,2013-01-01,19(10)