气候变化领域集成服务门户(CCPortal): Nitrogen Fixation at the Mid-Atlantic Bight Shelfbreak and Transport of Newly Fixed Nitrogen to the Slope Sea

CCPortal

DOI	10.1029/2023JC020651
	Nitrogen Fixation at the Mid-Atlantic Bight Shelfbreak and Transport of Newly Fixed Nitrogen to the Slope Sea
	Selden, C. R.; Mulholland, M. R.; Crider, K. E.; Clayton, S.; Macias-Tapia, A.; Bernhardt, P.; McGillicuddy Jr, D. J.; Zhang, W. G.; Chappell, P. D.
发表日期	2024
ISSN	2169-9275
EISSN	2169-9291
起始页码	129
结束页码	4
卷号	129 期号:4
英文摘要	Continental shelves contribute a large fraction of the ocean's new nitrogen (N) via N-2 fixation; yet, we know little about how physical processes at the ocean's margins shape diazotroph biogeography and activity. Here, we test the hypothesis that frontal mixing favors N-2 fixation at the Mid-Atlantic Bight shelfbreak. Using the N-15(2) bubble release method, we measured N-2 fixation rates on repeat cross-frontal transects in July 2019. N-2 fixation rates in shelf waters (median = 5.42 nmol N L-1 d(-1)) were higher than offshore (2.48 nmol N L-1 d(-1)) but did not significantly differ front frontal waters (8.42 nmol N L-1 d(-1)). However, specific N-2 uptake rates, indicative of the relative contribution of diazotroph-derived N to particulate N turnover, were significantly higher in frontal waters, suggesting that diazotroph-derived N is of greater importance in supporting productivity there. This study furthered captured an ephemeral shelf-water streamer, which resulted from the impingement of a warm core ring on the shelf. The streamer transported shelf-water diazotrophs (including UCYN-A and Richelia spp., as assessed by qPCR) offshore with sustained high N-2 fixation rates. This feature injected >50 metric tons d(-1) of newly fixed N to the Slope Sea-a rate equivalent to similar to 4% of the total N flux estimated for the entire Mid-Atlantic Bight. As intrusions of Gulf Stream meanders and eddies onto the shelf are increasing in frequency due to climate change, episodic lateral fluxes of new N into the Slope Sea may become increasingly important to regional budgets and ecosystem productivity.
英文关键词	N-2 fixation; diazotroph; front; Gulf Stream; Mid-Atlantic Bight; warm-core ring; streamer
语种	英语
WOS研究方向	Oceanography
WOS类目	Oceanography
WOS记录号	WOS:001197518000001
来源期刊	JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/302942
作者单位	Rutgers University System; Rutgers University New Brunswick; Old Dominion University; NERC National Oceanography Centre; National Oceanic Atmospheric Admin (NOAA) - USA; Woods Hole Oceanographic Institution; State University System of Florida; University of South Florida
推荐引用方式 GB/T 7714	Selden, C. R.,Mulholland, M. R.,Crider, K. E.,et al. Nitrogen Fixation at the Mid-Atlantic Bight Shelfbreak and Transport of Newly Fixed Nitrogen to the Slope Sea[J],2024,129(4).
APA	Selden, C. R..,Mulholland, M. R..,Crider, K. E..,Clayton, S..,Macias-Tapia, A..,...&Chappell, P. D..(2024).Nitrogen Fixation at the Mid-Atlantic Bight Shelfbreak and Transport of Newly Fixed Nitrogen to the Slope Sea.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,129(4).
MLA	Selden, C. R.,et al."Nitrogen Fixation at the Mid-Atlantic Bight Shelfbreak and Transport of Newly Fixed Nitrogen to the Slope Sea".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 129.4(2024).