Benavides, M. and Agawin, N.S.R. and Arístegui, J. and Ferrio, P. and Stal, L.J. (2011) Nitrogen fixation by Trichodesmium and small diazotrophs in the subtropical northeast Atlantic. Aquatic Microbial Ecology, 65, 43-53. ISSN 0948-3055.
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Official URL: http://dx.doi.org/10.3354/ame01534
We measured gross and net nitrogen fixation in fractionated samples (organisms >10 µm and <10 µm), and the density of Trichodesmium, during a cruise along the northeast Atlantic boundary current system and during 2 mesoscale experiments in the upwelling systems of Cape Silleiro (northwest Iberia) and Cape Ghir (northwest Africa). The density of Trichodesmium (<0.5 trichomes l−1) and its associated rates of nitrogen fixation (<0.1 μmol N m−2 d−1) were low. Trichomes appeared to accumulate at frontal sites—such as upwelling filaments and the Azores Front. Gross and net rates of nitrogen fixation were always <0.4 nmol N l−1d−1 except off the northwest African coast where a gross nitrogen fixation peak of 0.98 nmol N l−1 d−1 was measured. The <10 µm fraction contributed more to both gross and net nitrogen fixation than did the >10 µm fraction in most of the areas studied. The <10 µm fraction was responsible for 70 to 92% of the total nitrogen fixation in cold nutrient-rich areas. The contribution of small diazotrophs to nitrogen fixation in the upwelling sites suggests that the distribution and activity of these organisms are more widespread than previously thought.
|Institutes:||Nederlands Instituut voor Ecologie (NIOO)|
|Deposited On:||10 Oct 2011 02:00|
|Last Modified:||24 Apr 2012 16:41|
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