Combined effects of different CO2 levels and N sources on the diazotrophic cyanobacterium Trichodesmium, supplement to: Eichner, Meri; Kranz, Sven A; Rost, Bjoern (2014): Combined effects of different CO2 levels and N sources on the diazotrophic cyanobacterium Trichodesmium. Physiologia Plantarum, 152(2), 316-330

• Main Authors: Eichner, Meri, Kranz, Sven A, Rost, Bjoern
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2014
• Subjects: Bacteria; Bottles or small containers/Aquaria <20 L; Cyanobacteria; Growth/Morphology; Laboratory experiment; Laboratory strains; Macro-nutrients; Not applicable; Other metabolic rates; Pelagos; Phytoplankton; Primary production/Photosynthesis; Respiration; Single species; Trichodesmium erythraeum; Species; Figure; Treatment; Salinity; Temperature, water; Irradiance; pH; pH, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide, standard deviation; Growth rate; Growth rate, standard deviation; Carbon, organic, particulate per chlorophyll a; Carbon, organic, particulate, standard deviation; Nitrogen, organic, particulate per chlorophyll a; Nitrogen, organic, particulate, standard deviation; Particulate organic carbon production, per chlorophyll a; Particulate organic carbon, production, standard deviation; Particulate organic nitrogen production, per chlorophyll a; Particulate organic nitrogen production, standard deviation; Carbon, organic, particulate/Nitrogen, organic, particulate ratio; Carbon, organic, particulate/Nitrogen, organic, particulate ratio, standard deviation; Identification; Time in hours; LightDark cycle; Nitrogen fixation rate per chlorophyll a; Time point, descriptive; Net oxygen evolution, per chlorophyll a; Net oxygen evolution, per chlorophyll a, standard deviation; Carbon, inorganic, dissolved, half saturation concentration; Carbon, inorganic, dissolved, half saturation concentration, standard deviation; Maximum photochemical quantum yield of photosystem II; Maximum photochemical quantum yield of photosystem II, standard deviation; Effective absorbance cross-section of photosystem II; Effective absorbance cross-section of photosystem II, standard deviation; Re-oxidation time of the Qa acceptor; Re-oxidation time of the Qa acceptor, standard deviation; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Bicarbonate ion; Carbonate ion; Aragonite saturation state; Calcite saturation state; Potentiometric; Potentiometric titration; Coulometric titration; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Sven; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.834556; https://doi.pangaea.de/10.1594/PANGAEA.834556

To predict effects of climate change and possible feedbacks, it is crucial to understand the mechanisms behind CO2 responses of biogeochemically relevant phytoplankton species. Previous experiments on the abundant N2 fixers Trichodesmium demonstrated strong CO2 responses, which were attributed to an energy reallocation between its carbon (C) and nitrogen (N) acquisition. Pursuing this hypothesis, we manipulated the cellular energy budget by growing Trichodesmium erythraeum IMS101 under different CO2 partial pressure (pCO2) levels (180, 380, 980 and 1400?µatm) and N sources (N2 and NO3-). Subsequently, biomass production and the main energy-generating processes (photosynthesis and respiration) and energy-consuming processes (N2 fixation and C acquisition) were measured. While oxygen fluxes and chlorophyll fluorescence indicated that energy generation and its diurnal cycle was neither affected by pCO2 nor N source, cells differed in production rates and composition. Elevated pCO2 increased N2 fixation and organic C and N contents. The degree of stimulation was higher for nitrogenase activity than for cell contents, indicating a pCO2 effect on the transfer efficiency from N2 to biomass. pCO2-dependent changes in the diurnal cycle of N2 fixation correlated well with C affinities, confirming the interactions between N and C acquisition. Regarding effects of the N source, production rates were enhanced in NO3-grown cells, which we attribute to the higher N retention and lower ATP demand compared with N2 fixation. pCO2 effects on C affinity were less pronounced in NO3- users than N2 fixers. Our study illustrates the necessity to understand energy budgets and fluxes under different environmental conditions for explaining indirect effects of rising pCO2. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Lavigne et al, 2014) 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). The date of carbonate chemistry calculation is 2014-07-30.