Biogeochemical signatures of nitrogen fixation in the eastern North Atlantic
Biogeochemical signatures of nitrogen fixation in the eastern North Atlantic
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北大西洋东部固氮的生物地球化学特征
DOI：
10.1029/2002gl016542
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发表时间：
2003
影响因子：
5.2
通讯作者：
M. Woodward
中科院分区：
文献类型：
--
作者：
C. Mahaffey;Richard G. Williams;G. Wolff;N. Mahowald;W. Anderson;M. Woodward
2000年春季对北大西洋东部上空颗粒有机物的稳定氮同位素测定表明，在沿着20°W的26°N和32°N之间存在一个15 N相对于14 N天然丰度较低的区域。这种光同位素信号，加上植物色素的数据和持续升高的硝酸盐，磷酸盐的比例在上层温跃层，表明固氮提供了一个本地的主要供应氮的浮游植物在北大西洋东部的一部分。这些独立的地球化学代理是一致的增强大气尘埃沉降的区域，建议由大气传输模式。因此，大气沙尘事件可能在空间和时间上限制N2固定剂的分布。
Stable nitrogen isotopic determination of particulate organic matter over the eastern North Atlantic in spring 2000 reveal a region of low natural abundance of 15N relative to 14N between 26°N and 32°N along 20°W. This light isotopic signal, together with phytopigment data and persistently elevated nitrate to phosphate ratios in the upper thermocline, suggest that nitrogen fixation provides a local dominant supply of nitrogen to phytoplankton over part of the eastern North Atlantic. These independent biogeochemical proxies are coincident with a region of enhanced atmospheric dust deposition, as suggested by an atmospheric transport model. Hence, the atmospheric dust events may spatially and temporally constrain the distribution of N2 fixers.