Distribution of major diazotrophs in the surface water of the Kuroshio from northeastern Taiwan to south of mainland Japan
Distribution of major diazotrophs in the surface water of the Kuroshio from northeastern Taiwan to south of mainland Japan
复制标题
台湾东北部至日本大陆南部黑潮表层水中主要固氮生物的分布
DOI：
10.1093/plankt/fby027
复制
发表时间：
2018
影响因子：
2.1
通讯作者：
Takeda Shigenobu
中科院分区：
文献类型：
--
作者：
Shiozaki Takuhei;Kondo Yoshiko;Yuasa Daisuke;Takeda Shigenobu
我们调查了太平洋固氮“热点”--黑潮水域以及邻近海域和北太平洋热带环流(NPTG)水域中重氮菌的组成和分布。具体地说，我们研究了七种常见的重氮菌中nifHi的丰度：毛霉、Crocosphaera、Ucyn-A、Ucyn-C、与根霉(RR)或半乳杆菌(HR)相关的黎氏菌和一种伽马蛋白细菌(γ-24774A11)。黑潮表层固氮菌群落与其他水域不同的是毛霉、RR、HR和UCyN-C丰度较高。这些重氮菌的分布不能很好地解释温度和常量营养素浓度，尽管它们可能受到电流和微量营养素含量的影响。γ-24774A11广泛存在于富营养化水体中，其丰度与水温显著相关。Crocosphaa和UCyn-A1的表面丰度在黑潮中从上游向下游递减，其丰度在黑潮低于NPTG。黑潮的温度和硝酸盐+亚硝酸盐水平与NPTG相当，但磷酸盐和叶绿素水平分别较低和较高。这些结果表明，Crocosphaa和UCyn-A1在黑潮中的生长可能受到磷有效性的调节，但由于与非重氮菌和其他重氮菌的激烈竞争，磷的有效性将受到严重限制。
We investigated the composition and distribution of diazotrophs in waters of the Kuroshio, the “hot spot” of nitrogen fixation in the Pacific Ocean, as well as in adjacent waters and the North Pacific tropical gyre (NPTG). Specifically, we explored the abundance ofnifHin seven commonly observed diazotrophs:Trichodesmium,Crocosphaera, UCYN-A, UCYN-C,Richeliaassociated withRhizosolenia(RR) orHemiaulus(HR) and a gammaproteobacterium (γ-24774A11). The surface diazotroph community in the Kuroshio was distinguished from those in other waters by its higher abundances ofTrichodesmium, RR, HR and UCYN-C. The distributions of these diazotrophs were not well explained by temperature and macronutrient concentrations, although they may be influenced by the current flow and micronutrient content. γ-24774A11 occurred extensively in the oligotrophic waters, and its abundance was significantly correlated with water temperature. The surface abundances ofCrocosphaeraand UCYN-A1 decreased from upstream to downstream in the Kuroshio, and their abundances were lower in the Kuroshio than in the NPTG. Temperature and nitrate + nitrite levels were comparable between the Kuroshio and NPTG, but phosphate and chlorophyllalevel were lower and higher, respectively, in the Kuroshio. These results suggest that the growth ofCrocosphaeraand UCYN-A1 in the Kuroshio may be regulated by phosphorus availability, which would be severely limited due to intense competition with non-diazotrophs and other diazotrophs.