气候变化领域集成服务门户(CCPortal): Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre

CCPortal

DOI	10.1029/2019JC015600
	Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre
	Mino Y.; Sukigara C.; Honda M.C.; Kawakami H.; Wakita M.; Sasaoka K.; Yoshikawa C.; Abe O.; Kaiser J.; Kimoto K.; Kitamura M.; Fujiki T.; Matsumoto K.; Saino T.
发表日期	2020
ISSN	21699275
卷号	125 期号:5
英文摘要	Time series of particulate nitrogen isotope delta (PN-δ15N) and flux of trapped particles at 200 m were determined in the northwestern North Pacific subtropical gyre between 2010 and 2014 in order to examine temporal variations in mixed layer nitrate availability and downward particle export. Lower PN-δ15N (<4‰) seen every winter corresponded to convective nitrate supply triggering phytoplankton blooms. Greater particle fluxes were associated with higher CaCO3 concentrations (mass fraction >50%), implying that new nitrogen supply stimulated predominantly coccolithophore growth and downward transport of coccoliths. Even in the stratified summer of 2011, a δ15N drop associated with a spike in particulate flux was found and was attributed to the uplift of nitrate-rich deep waters due to a mesoscale cyclonic eddy passing the mooring station. Total nitrate input sustains 86–93% of annual new production in this region while nitrogen fixation accounts for the rest. Trapped particles also showed that the winter δ15N decrease appeared earlier in the 2011–2012 blooms than those in 2013–2014, coinciding with 8% higher CaCO3 concentrations and a 40% lower particulate organic carbon to inorganic carbon export ratio, R(POC:PIC). This reflected stronger convective mixing and hence larger nutrient supply in 2011–2012, caused by larger ocean heat loss related to winter monsoon intensity. Such interannual change of winter R(POC:PIC) can affect CO2 uptake rate in the northwestern North Pacific subtropical gyre where anthropogenic CO2 accumulates in subtropical mode waters. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	coccolithophore; delta N-15 of particles; nitrate supply; POC:PIC export ratio; the western north pacific subtropical gyre; time-series sediment trap
语种	英语
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/186877
作者单位	Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan; Center for Marine Research and Operations, Tokyo University of Marine Science and Technology, Tokyo, Japan; Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan; Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan; Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
推荐引用方式 GB/T 7714	Mino Y.,Sukigara C.,Honda M.C.,et al. Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre[J],2020,125(5).
APA	Mino Y..,Sukigara C..,Honda M.C..,Kawakami H..,Wakita M..,...&Saino T..(2020).Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre.Journal of Geophysical Research: Oceans,125(5).
MLA	Mino Y.,et al."Seasonal and Interannual Variations in Nitrogen Availability and Particle Export in the Northwestern North Pacific Subtropical Gyre".Journal of Geophysical Research: Oceans 125.5(2020).