Spatial variation in N 2 -fixation rate and diazotroph activity in the Tropical Atlantic

• Main Authors: Montoya, J. P., Voss, M., Capone, D. G.
• Other Authors: Georgia Institute of Technology Atlanta, Leibniz-Institut für Ostseeforschung Warnemünde (IOW), Leibniz Association, University of Southern California (USC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]; [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-00297855; https://hal.archives-ouvertes.fr/hal-00297855/document; https://hal.archives-ouvertes.fr/hal-00297855/file/bgd-3-1739-2006.pdf

International audience A variety of N 2 -fixers occur in the tropical Atlantic and these diazotrophs make a substantial contribution to the nitrogen budget of the upper water column. A synthesis of previously published and novel rate measurements for the Tropical North Atlantic provides insight into the role of two different diazotroph groups in supporting N 2 fixation in the tropical Atlantic. The overall rate of N 2 -fixation by the two groups of diazotrophs was similar in the eastern and western parts of the basin, but N 2 -fixation by \textit{Trichodesmium} was strongly dominant in the western part of the basin while small diazotrophs played a much larger role to the east of 40° W. The reasons for this shift in dominance are unclear, as is the identity of the small organisms fixing N 2 in the water column.