Modelling the dynamics of carbon–nitrogen metabolism in the unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501, under variable light regimes

Type : ACL
Nature : Production scientifique
Au bénéfice du Laboratoire : Oui
Statut de publication : Publié
Année de publication : 2014
Auteurs (5) : GRIMAUD Ghjuvan,micaelu RABOUILLE Sophie DRON Anthony SCIANDRA Antoine BERNARD Olivier
Revue scientifique : Ecological Modelling
Volume : 291
Fascicule : 0
Pages : 121-133
DOI : 10.1016/j.ecolmodel.2014.07.016
URL : http://www.sciencedirect.com/science/article/pii/s0304380014003524
Abstract : A dynamical model is proposed that describes the daily dynamics of diazotrophy in a unicellular cyanobacterium, Crocosphaera watsonii WH8501, in regard to light limitation and obligate diazotrophy. In this model, intracellular carbon and nitrogen are both divided into a functional pool and a storage pool. An internal pool that explicitly describes the nitrogenase enzyme is also added. The various intracellular carbon and nitrogen flows between these pools lead to a complex dynamics driven by the light regime. The model is successfully validated with continuous cultures experiments of C. watsonii under three light regimes, indicating that the proposed mechanisms accurately reproduce the growth dynamics of this organism under various light environments. Then, a series of model simulations is run for a range of light regimes with different photoperiods and daily light doses. Results reveal how nitrogen and carbon are coupled, through the diel cycle, along with nitrogenase dynamics whose activity is constrained by the light regime. In an ecological perspective, we picture the effect of such irradiance condition on growth and on the carbon to nitrogen stoichiometry on cells. This model could prove useful to understand the latitudinal distribution of this cyanobacterium in the global ocean.
Mots-clés : Nitrogen fixation Continuous culture UCYN Growth model Reserves Carbon
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Tags : PHYTOPULSE
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Citation :
Grimaud GM, Rabouille S, Dron A, Sciandra A, Bernard O (2014) Modelling the dynamics of carbon–nitrogen metabolism in the unicellular diazotrophic cyanobacterium Crocosphaera watsonii WH8501, under variable light regimes. Ecol Model 291: 121-133 | doi: 10.1016/j.ecolmodel.2014.07.016