Seawater carbonate chemistry and combined physiological effects of CO2 and light on the N2-fixing cyanobacterium Trichodesmium IMS101 during experiments, 2010, supplement to: Kranz, Sven A; Levitan, Orly; Richter, Klaus-Uwe; Prasil, O; Beran-Frank, Ilana; Rost, Bjoern (2010): Combined effects of CO2 and light on the N2-fixing cyanobacterium Trichodesmium IMS101: Physiological responses. Plant Physiology, 154, 334-345

• Main Authors: Kranz, Sven A, Levitan, Orly, Richter, Klaus-Uwe, Prasil, O, Beran-Frank, Ilana, Rost, Bjoern
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2010
• Subjects: Bacteria; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria <20 L; Cyanobacteria; Growth/Morphology; Laboratory experiment; Laboratory strains; Light; Not applicable; Other metabolic rates; Pelagos; Phytoplankton; Primary production/Photosynthesis; Respiration; Single species; Trichodesmium sp.; Comment; Salinity; Temperature, water; Radiation, photosynthetically active; Experimental treatment; Partial pressure of carbon dioxide water at sea surface temperature wet air; Carbon dioxide; Carbon dioxide, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; pH; pH, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Growth rate; Growth rate, standard deviation; Carbon, organic, particulate, per cell; Particulate organic carbon content per cell, standard deviation; Particulate organic nitrogen per cell; Particulate organic nitrogen per cell, standard deviation; Particulate organic phosphorus per cell; Particulate organic phosphorus per cell, standard deviation; Carbon/Nitrogen ratio; Carbon/Nitrogen ratio, standard deviation; Chlorophyll a per cell; Chlorophyll a, standard deviation; Production of particulate organic carbon per cell; Particulate organic carbon, production, standard deviation; Production of particulate organic nitrogen; Particulate organic nitrogen production, standard deviation; Gross oxygen evolution, per chlorophyll a; Gross oxygen evolution, standard deviation; Oxygen consumption per chlorophyll a; Oxygen consumption, standard deviation; Fixation of carbon in chlorophyll; Fixation of carbon in chlorophyll, standard deviation; Bicarbonate uptake rate in chlorophyll; Bicarbonate uptake in chlorophyll, standard deviation; Carbon dioxide uptake rate in chlorophyll; Carbon dioxide uptake in chlorophyll, standard deviation; Time in hours; Nitrogen fixation rate per chlorophyll a; Nitrogen fixation rate, standard deviation; Carbonate system computation flag; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; Calculated using CO2SYS; Alkalinity, Gran titration Gran, 1950; pH meter Metrohm electrodes; Calculated, see references; Mass spectrometer ANCA-SL 20-20 Europa Scientific; Calculated; see references; Determined by acetylene reduction assay using a gas chromatograph; Calculated using seacarb after Nisumaa et al. 2010; European network of excellence for Ocean Ecosystems Analysis EUR-OCEANS; European Project on Ocean Acidification EPOCA; Ocean Acidification International Coordination Centre OA-ICC; Klaus; Sven; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.777430; https://doi.pangaea.de/10.1594/PANGAEA.777430

Recent studies on the diazotrophic cyanobacterium Trichodesmium erythraeum(IMS101) showed that increasing CO2 partial pressure (pCO2) enhances N2 fixation and growth. Significant uncertainties remain as to the degree of the sensitivity to pCO2, its modification by other environmental factors, and underlying processes causing these responses. To address these questions, we examined the responses ofTrichodesmium IMS101 grown under a matrix of low and high levels of pCO2 (150 and 900 µatm) and irradiance (50 and 200 µmol photons m-2 s-1). Growth rates as well as cellular carbon and nitrogen contents increased with increasing pCO2 and light levels in the cultures. The pCO2-dependent stimulation in organic carbon and nitrogen production was highest under low light. High pCO2 stimulated rates of N2fixation and prolonged the duration, while high light affected maximum rates only. Gross photosynthesis increased with light but did not change with pCO2. HCO3- was identified as the predominant carbon source taken up in all treatments. Inorganic carbon uptake increased with light, but only gross CO2 uptake was enhanced under high pCO2. A comparison between carbon fluxes in vivo and those derived from 13C fractionation indicates high internal carbon cycling, especially in the low-pCO2treatment under high light. Light-dependent oxygen uptake was only detected underlow pCO2 combined with high light or when low-light-acclimated cells were exposed to high light, indicating that the Mehler reaction functions also as a photoprotective mechanism in Trichodesmium. Our data confirm the pronounced pCO2 effect on N2fixation and growth in Trichodesmium and further show a strong modulation of these effects by light intensity. We attribute these responses to changes in the allocation of photosynthetic energy between carbon acquisition and the assimilation of carbon and nitrogen under elevated pCO2. These findings are supported by a complementarystudy looking at photosynthetic fluorescence parameters of photosystem II, photosynthetic unit stoichiometry (photosystem I:photosystem II), and pool sizes of key proteins in carbon and nitrogen acquisition. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne and Gattuso, 2011) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI).