1. N2 fixation rate and diazotroph community structure in the western tropical North Pacific Ocean
- Author
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Zhibing Jiang, Minfang Zheng, Min Chen, Jie Huang, Dongsheng Zhang, Chunsheng Wang, Yusheng Qiu, and Run Zhang
- Subjects
Cyanobacteria ,Biogeochemical cycle ,010504 meteorology & atmospheric sciences ,biology ,Chemistry ,Community structure ,chemistry.chemical_element ,Aquatic Science ,010502 geochemistry & geophysics ,Oceanography ,biology.organism_classification ,01 natural sciences ,Nitrogen ,Nutrient ,Trichodesmium ,Botany ,Dominance (ecology) ,Diazotroph ,0105 earth and related environmental sciences - Abstract
In the present study, we report N2 fixation rate (15N isotope tracer assay) and the diazotroph community structure (using the molecular method) in the western tropical North Pacific Ocean (WTNP) (13°–20°N, 120°–160°E). Our independent evidence on the basis of both in situ N2 fixation activity and diazotroph community structure showed the dominance of unicellular N2 fixation over majority of the WTNP surface waters during the sampling periods. Moreover, a shift in the diazotrophic composition from unicellular cyanobacteria group B-dominated to Trichodesmium spp.-dominated toward the western boundary current (Kuroshio) was also observed in 2013. We hypothesize that nutrient availability may have played a major role in regulating the biogeography of N2 fixation. In surface waters, volumetric N2 fixation rate (calculated by nitrogen) ranged between 0.6 and 2.6 nmol/(L·d) and averaged (1.2±0.5) nmol/(L·d), with
- Published
- 2019