abundance and distribution of major groups of diazotrophic cyanobacteria and their potential contribution to n₂ fixation in the tropical atlantic ocean.the abundances of six n₂-fixing cyanobacterial phylotypes were profiled at 22 stations across the tropical atlantic ocean during june 2006, and used to model the contribution of the diazotrophs to n₂ fixation. diazotroph abundances were measured by targeting the nifh gene of trichodesmium, unicellular groups a, b, c (ucyn-a, ucyn-b and ucyn-c), and diatom-cyanobiont symbioses hemiaulus-richelia, rhizosolenia-richelia and chaetoceros-calothrix. west to east gradients in temperature, salinity and ...201020678117
nitrogen fixation and nitrogenase (nifh) expression in tropical waters of the eastern north atlantic.expression of nifh in 28 surface water samples collected during fall 2007 from six stations in the vicinity of the cape verde islands (north-east atlantic) was examined using reverse transcription-polymerase chain reaction (rt-pcr)-based clone libraries and quantitative rt-pcr (rt-qpcr) analysis of seven diazotrophic phylotypes. biological nitrogen fixation (bnf) rates and nutrient concentrations were determined for these stations, which were selected based on a range in surface chlorophyll conc ...201121228888
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