Category Archives: Nitrogen Fixation


Fellow Travelers

Observations suggest diazotrophs like Crocosphaera and Trichodesmium pay for their ability to fix nitrogen with a very low growth rate, yet diatom-diazotroph associations or DDAs exhibit high growth rates. CBIOMES postdoctoral fellow Chris Follett and co-authors use a cell flux model to test the hypothesis that diatom-diazotroph associations or DDAs grow faster than unpaired diazotrophs because the diatoms in DDAs provide organic carbon to their diazotroph guests that boost their growth rate. Continue reading


Phytoplankton & Chips

Helen Hill | Darwin Project

Microbes mediate the global marine cycles of elements, modulating atmospheric CO2 and helping to maintain the oxygen we all breath yet there is much about them scientists still don’t understand. Now, an award from the Simons Foundation will give researchers from the Darwin Project access to bigger, better computing resources to model these communities and probe how they work. Continue reading

NO3, Fe, and diazotroph biomass - observations (left) and model (right) over top 50 m - from Fig 1, Dutkiewicz et al, 2014

Life on the Edge – How shifting marine province boundaries could provide a new metric for global change

In their new competition theory paper, appearing in the 2014 issue of Biogeosciences, Dutkiewicz et al examine the sensitivity of the biogeography of nitrogen fixers to a warming climate and increased aeolian iron deposition in the context of a global earth system model. Continue reading

Dutkiewicz, S., Ward, B. A., Scott, J. R., and Follows, M. J. (2014) Understanding predicted shifts in diazotroph biogeography using resource competition theory, Biogeosciences, 11, 5445-5461, doi: 10.5194/bg-11-5445-2014.

Moore, R.M., M. Kienast, M. Fraser, J. Cullen, C. Deutsch, S. Dutkiewicz, M.J. Follows, and C.J. Somes (2014), Substantial underestimation of nitrogen fixation suggested by hydrogen supersaturations in the Atlantic, Journal of Geophysical Research - Oceans , 119, 4340-4350, doi: 10.1002/2014JC010017.