Premium
The relative availability of inorganic carbon and inorganic nitrogen influences the response of the dinoflagellate Protoceratium reticulatum to elevated CO 2
Author(s) -
Pierangelini Mattia,
Raven John A.,
Giordano Mario
Publication year - 2017
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/jpy.12463
Subject(s) - dinoflagellate , biology , nitrogen , phytoplankton , biomass (ecology) , zoology , rubisco , total inorganic carbon , abundance (ecology) , nutrient , ecological stoichiometry , botany , photosynthesis , environmental chemistry , carbon dioxide , ecology , chemistry , organic chemistry
This work originates from three facts: (i) changes in CO 2 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 CO 2 regimes (400, 1,000, and 5,000 ppmv, pH of 8.1) and either variable (the NO 3 − concentration was always 2.5 mmol · L −1 ) or constant ( NO 3 − concentration varied to maintain the same C i / NO 3 − ratio at all pCO 2 ) C i / NO 3 − ratio. Regardless of N availability, cells had higher specific growth rates, but lower cell dry weight and C and N quotas, at elevated CO 2 . The carbohydrate pool size and the C/N was unaltered in all treatments. The lipid content only decreased at high pCO 2 at constant C i / NO 3 − ratio. In the variable C i / NO 3 − conditions, the relative abundance of Rubisco (and other proteins) also changed; this did not occur at constant C i / NO 3 − . Thus, the biomass quality of P. reticulatum for grazers was affected by the C i / NO 3 − 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.