DOI: 10.1029/2018GB006130
论文题名: High Rates of N2 Fixation in Temperate, Western North Atlantic Coastal Waters Expand the Realm of Marine Diazotrophy
作者: Mulholland M.R. ; Bernhardt P.W. ; Widner B.N. ; Selden C.R. ; Chappell P.D. ; Clayton S. ; Mannino A. ; Hyde K.
刊名: Global Biogeochemical Cycles
ISSN: 0886-6236
EISSN: 1944-9224
出版年: 2019
卷: 33, 期: 7 语种: 英语
英文关键词: biogeography
; coastal water
; concentration (composition)
; continental shelf
; cruise report
; cyanobacterium
; enzyme
; genetic analysis
; nitrogen fixation
; nutrient limitation
; oligotrophic environment
; primary production
; Atlantic Ocean
; Atlantic Ocean (North)
; Canada
; Cape Hatteras
; Hatteras Island
; North Carolina
; Nova Scotia
; United States
; Cyanobacteria
学科: diazotrophy
; nitrogen fixation
; North American continental shelf
中文摘要: Dinitrogen (N2) fixation can alleviate N limitation of primary productivity by introducing fixed nitrogen (N) to the world's oceans. Although measurements of pelagic marine N2 fixation are predominantly from oligotrophic oceanic regions, where N limitation is thought to favor growth of diazotrophic microbes, here we report high rates of N2 fixation from seven cruises spanning four seasons in temperate, western North Atlantic coastal waters along the North American continental shelf between Cape Hatteras and Nova Scotia, an area representing 6.4% of the North Atlantic continental shelf area. Integrating average areal rates of N2 fixation during each season and for each domain in the study area, the estimated N input from N2 fixation to this temperate shelf system is 0.02 Tmol N/year, an amount equivalent to that previously estimated for the entire North Atlantic continental shelf. Unicellular group A cyanobacteria (UCYN-A) were most often the dominant diazotrophic group expressing nifH, a gene encoding the nitrogenase enzyme, throughout the study area during all seasons. This expands the domain of these diazotrophs to include coastal waters where dissolved N concentrations are not always depleted. Further, the high rates of N2 fixation and diazotroph diversity along the western North Atlantic continental shelf underscore the need to reexamine the biogeography and the activity of diazotrophs along continental margins. Accounting for this substantial but previously overlooked source of new N to marine systems necessitates revisions to global marine N budgets. ©2019. The Authors. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/160161
Appears in Collections: 气候变化与战略
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作者单位: Department of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Norfolk, VA, United States; Now at Woods Hole Oceanographic Institute, Woods Hole, MA, United States; Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD, United States; Northeast Fisheries Science Center, National Oceanic and Atmospheric Administration, Narragansett, RI, United States
Recommended Citation:
Mulholland M.R.,Bernhardt P.W.,Widner B.N.,et al. High Rates of N2 Fixation in Temperate, Western North Atlantic Coastal Waters Expand the Realm of Marine Diazotrophy[J]. Global Biogeochemical Cycles,2019-01-01,33(7)