DOI: 10.1007/s10533-015-0175-3
Scopus记录号: 2-s2.0-84959516921
论文题名: Nitrogen cycling in a freshwater estuary
作者: Loken L.C. ; Small G.E. ; Finlay J.C. ; Sterner R.W. ; Stanley E.H.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2016
卷: 127, 期: 2018-02-03 起始页码: 199
结束页码: 216
语种: 英语
英文关键词: Denitrification
; Lake Superior
; Nitrate
; Nitrification
; Saint Louis River Estuary
Scopus关键词: ammonium
; baseflow
; biogeochemical cycle
; denitrification
; dissolved inorganic nitrogen
; ecotone
; estuarine environment
; freshwater
; nitrate
; nitrification
; nitrogen cycle
; organic matter
; river flow
; Great Lakes [North America]
; Lake Superior
; Saint Louis Estuary
; United States
英文摘要: Freshwater estuaries may be important control points but have received limited research attention, emblematic of a general under-appreciation of these ecosystems and the services they provide. These ecotone environments exist at the interface of rivers flowing into large lakes, where seiches cause mixing of lotic and lentic waters within flooded river deltas. We assessed the dissolved inorganic nitrogen (DIN) retention and processing controls in the Saint Louis River Estuary (SLRE), which receives inputs from rivers, urban sources, and Lake Superior. Nitrate (NO3–N) was the dominant form of DIN and was consistently highest in the lower estuary due to seiche-delivered Lake Superior water and nitrification of ammonium from urban sources. The estuary transitioned from a net NO3–N source during high flows to a net sink during summer baseflow conditions. NO3–N availability controlled site-specific denitrification rates while sediment organic matter explained the spatial pattern in denitrification potential. As the estuary shifted from a riverine state to one with more lake influence, seiches delivered Lake Superior NO3–N to the lower portion of the estuary, alleviating the final denitrification control and activating the estuary’s ‘denitrification pump’. This amplified removal condition is maintained by critically delivered NO3–N during periods of warm temperatures and long residence times. Often these controls are unsynchronized in streams where NO3–N is typically lowest during summer baseflow. Similar ephemeral biogeochemical processes are likely found within other seiche-prone lakes where organic-rich sediments accumulate at river mouths and are supplied with chemically distinct lake water during low flow periods. © 2016, Springer International Publishing Switzerland.
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83419
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: Center for Limnology, University of Wisconsin-Madison, 680 N Park. St., Madison, WI, United States; Department of Biology, University of St. Thomas, 2115 Summit Ave., St. Paul, MN, United States; Department of Ecology, Evolution, and Behavior, University of Minnesota-Twin Cities, 1987 Upper Buford Circle, St. Paul, MN, United States; Large Lakes Observatory, University of Minnesota-Duluth, 2205 E 5th St., Duluth, MN, United States
Recommended Citation:
Loken L.C.,Small G.E.,Finlay J.C.,et al. Nitrogen cycling in a freshwater estuary[J]. Biogeochemistry,2016-01-01,127(2018-02-03)