气候变化领域集成服务门户(CCPortal): Dinitrogen Fixation Across Physico-Chemical Gradients of the Eastern Tropical North Pacific Oxygen Deficient Zone

CCPortal

DOI	10.1029/2019GB006242
	Dinitrogen Fixation Across Physico-Chemical Gradients of the Eastern Tropical North Pacific Oxygen Deficient Zone
	Selden C.R.; Mulholland M.R.; Bernhardt P.W.; Widner B.; Macías-Tapia A.; Ji Q.; Jayakumar A.
发表日期	2019
ISSN	0886-6236
EISSN	1944-9224
起始页码	1187
结束页码	1202
卷号	33 期号:9
英文摘要	The Eastern Tropical North Pacific Ocean hosts one of the world's largest oceanic oxygen deficient zones (ODZs). Hot spots for reactive nitrogen (Nr) removal processes, ODZs generate conditions proposed to promote Nr inputs via dinitrogen (N2) fixation. In this study, we quantified N2 fixation rates by 15N tracer bioassay across oxygen, nutrient, and light gradients within and adjacent to the ODZ. Within subeuphotic oxygen-deplete waters, N2 fixation was largely undetectable; however, addition of dissolved organic carbon stimulated N2 fixation in suboxic (<20 μmol/kg O2) waters, suggesting that diazotroph communities are likely energy limited or carbon limited and able to fix N2 despite high ambient concentrations of dissolved inorganic nitrogen. Elevated rates (>9 nmol N·L−1·day−1) were also observed in suboxic waters near volcanic islands where N2 fixation was quantifiable to 3,000 m. Within the overlying euphotic waters, N2 fixation rates were highest near the continent, exceeding 500 μmol N·m−2·day−1 at one third of inshore stations. These findings support the expansion of the known range of diazotrophs to deep, cold, and dissolved inorganic nitrogen-replete waters. Additionally, this work bolsters calls for the reconsideration of ocean margins as important sources of Nr. Despite high rates at some inshore stations, regional N2 fixation appears insufficient to compensate for Nr loss locally as observed previously in the Eastern Tropical South Pacific ODZ. ©2019. The Authors.
英文关键词	aphotic; diazotroph; eastern tropical pacific; nitrogen fixation; oxygen deficient zone; oxygen minimum zone
语种	英语
scopus关键词	dissolved organic carbon; nitrogen fixation; oxygen; oxygen minimum layer; physicochemical property; Pacific Ocean; Pacific Ocean (North); Pacific Ocean (South); Pacific Ocean (South)
来源期刊	Global Biogeochemical Cycles
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/129711
作者单位	Department of Ocean, Earth & Atmospheric Science, Old Dominion University, Norfolk, VA, United States; Now at Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, United States; Institute of Oceanological Research, Autonomous University of Baja California, Ensenada, Mexico; Department of Geosciences, Princeton University, Princeton, NJ, United States; Now at Helmholtz Center for Ocean Research Kiel, Kiel, Germany
推荐引用方式 GB/T 7714	Selden C.R.,Mulholland M.R.,Bernhardt P.W.,et al. Dinitrogen Fixation Across Physico-Chemical Gradients of the Eastern Tropical North Pacific Oxygen Deficient Zone[J],2019,33(9).
APA	Selden C.R..,Mulholland M.R..,Bernhardt P.W..,Widner B..,Macías-Tapia A..,...&Jayakumar A..(2019).Dinitrogen Fixation Across Physico-Chemical Gradients of the Eastern Tropical North Pacific Oxygen Deficient Zone.Global Biogeochemical Cycles,33(9).
MLA	Selden C.R.,et al."Dinitrogen Fixation Across Physico-Chemical Gradients of the Eastern Tropical North Pacific Oxygen Deficient Zone".Global Biogeochemical Cycles 33.9(2019).