Diazotrophic bacteria respond to Saharan dust additions
Diazotrophic bacteria respond to Saharan dust additions
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DOI：
10.3354/meps10109
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发表时间：
2012-01-01
影响因子：
2.5
通讯作者：
LaRoche, Julie
中科院分区：
文献类型：
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作者：
Langlois, Rebecca J.;Mills, Matthew M.;LaRoche, Julie
进行了三个生物测定实验，以研究营养物和撒哈拉尘埃添加对北大西洋热带自然固氮群落的影响。在 48 小时孵育开始和结束时收集用于核酸分析的样品。 TaqMan 探针特异于 7 种固氮营养系统型，即。丝状蓝藻 (Trichodesmium spp.)、单细胞蓝藻 (UCYN) A、B 和 C 组、Gamma A 和 P 变形菌以及 Cluster III 用于定量 nifH DNA 丰度。在相同的实验中使用N-15(2)气泡注入方法测量了N-2固定率。 N-2 固定受到 P 和 Fe 的共同限制。添加 Fe 或 P 或两者组合后，总 nifH 丰度相对于对照有所增加。与对照相比，单独添加溶解的 N 或与磷酸盐组合添加溶解的 N 会诱导 UCYN-A 和 Gamma A nifH 的增加。撒哈拉尘埃的添加显着提高了固定率。添加撒哈拉沙尘后，所有蓝藻和 Gamma A nifH 系统发育型的丰度至少翻倍，其中地表水溶解铁浓度为
Three bioassay experiments were performed to study the effects of nutrient and Saharan dust additions on natural diazotrophic communities in the tropical North Atlantic Ocean. Samples for nucleic acid analysis were collected at the beginning and end of 48 h incubations. TaqMan probes specific to 7 diazotrophic phylotypes, viz. filamentous cyanobacteria (Trichodesmium spp.), unicellular cyanobacterial (UCYN) Groups A, B, and C, Gamma A and P Proteobacteria, and Cluster III, were used to quantify nifH DNA abundances. N-2 fixation rates were measured in the same experiments using the N-15(2) gas bubble injection method. N-2 fixation was co-limited by P and Fe. Total nifH abundances increased relative to the control with additions of either Fe or P or both in combination. Additions of dissolved N, alone or in combination with phosphate, induced increases in UCYN-A and Gamma A nifH compared with the control. Saharan dust additions significantly stimulated fixation rates. Abundances of all cyanobacterial and Gamma A nifH phylotypes at least doubled after Saharan dust additions where surface water dissolved Fe concentrations were