The relative availability of inorganic carbon and inorganic nitrogen influences the response of the dinoflagellate Protoceratium reticulatum to elevated CO2

0474561 - MBÚ 2018 RIV US eng J - Journal Article
Pierangelini, M. - Raven, J.A. - Giordano, Mario
The relative availability of inorganic carbon and inorganic nitrogen influences the response of the dinoflagellate Protoceratium reticulatum to elevated CO2.
Journal of Phycology. Roč. 53, č. 2 (2017), s. 298-307. ISSN 0022-3646. E-ISSN 1529-8817
Institutional support: RVO:61388971
Keywords : cell composition * CO 2 * dinoflagellate
OECD category: Microbiology
Impact factor: 3.000, year: 2017

This work originates from three facts: (i) changes in CO2 availability influence metabolic processes in algal cells, (ii) Spatial and temporal variations of nitrogen availability cause repercussions on phytoplankton physiology, (iii) Growth and cell composition are dependent on the stoichiometry of nutritional resources. In this study, we assess whether the impact of rising pCO(2) is influenced by N availability, through the impact that it would have on the C/N stoichiometry, in conditions of N sufficiency. Our experiments used the dinoflagellate Protoceratium reticulatum, which we cultured under three CO2 regimes (400, 1,000, and 5,000 ppmv, pH of 8.1) and either variable (the NO3- concentration was always 2.5 mmol.L-1) or constant (NO3- concentration varied to maintain the same Ci/NO3- ratio at all pCO(2)) C-i/NO3- ratio. Regardless of N availability, cells had higher specific growth rates, but lower cell dry weight and C and N quotas, at elevated CO2. The carbohydrate pool size and the C/N was unaltered in all treatments. The lipid content only decreased at high pCO(2) at constant Ci/NO3- ratio. In the variable Ci/NO3- conditions, the relative abundance of Rubisco (and other proteins) also changed, this did not occur at constant Ci/NO3-. Thus, the biomass quality of P. reticulatum for grazers was affected by the Ci/NO3- ratio in the environment and not only by the pCO(2), both with respect to the size of the main organic pools and the composition of the expressed proteome.
Permanent Link: http://hdl.handle.net/11104/0271586