Publication Date:
2024-05-27
Description:
Phytoplankton in the upper oceans are exposed to changing light levels due to mixing, diurnal solar cycles and weather conditions. Consequently, effects of ocean acidification are superimposed upon responses to variable light levels. We therefore grew a model diatom Thalassiosira pseudonana under either constant or variable light but at the same daily photon dose, with current low (400 μatm, LC) and future high CO2 (1000 μatm, HC) treatments. Variable light, compared with the constant light regime, decreased the growth rate, Chl a, Chl c, and carotenoid contents under both LC and HC conditions. Cells grown under variable light appeared more tolerant of high light as indicated by higher maximum relative electron transport rate and saturation light. Light variation interacted with high CO2/lowered pH to decrease the carbon fixation rate, but increased particulate organic carbon (POC) and particularly nitrogen (PON) per cell, which drove a decrease in C/N ratio, reflecting changes in the efficiency of energy transfer from photo-chemistry to net biomass production. Our results imply that elevated pCO2 under varying light conditions can lead to less primary productivity but more PON per biomass of the diatom, which might improve the food quality of diatoms and thereby influence biogeochemical nitrogen cycles.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Aragonite saturation state, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calcite saturation state, standard deviation; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Calculated using seacarb after Orr et al. (2018); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbon, organic, particulate; Carbon, organic, particulate, per cell; Carbon, organic, particulate, production per cell; Carbon, organic, particulate, standard deviation; Carbon/Nitrogen ratio; Carbon/Nitrogen ratio, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Carbon fixation rate; Carbon fixation rate, standard deviation; Carotenoids, intracellular; Carotenoids, standard deviation; Carotenoids/Chlorophyll a ratio; Carotenoids/Chlorophyll a ratio, standard deviation; Carotenoids per cell; Cell size; Cell size, standard deviation; Chlorophyll a, intracellular; Chlorophyll a, standard deviation; Chlorophyll a per cell; Chlorophyll c, intracellular; Chlorophyll c, standard deviation; Chlorophyll c per cell; Chromista; Effective quantum yield; Effective quantum yield, standard deviation; Electron transport rate, relative; Electron transport rate, relative, standard deviation; Electron transport rate efficiency; Electron transport rate efficiency, standard deviation; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Fugacity of carbon dioxide in seawater, standard deviation; Growth/Morphology; Growth rate; Growth rate, standard deviation; Irradiance; Laboratory experiment; Laboratory strains; Light; Light saturation point; Light saturation point, standard deviation; Maximal electron transport rate, relative; Maximal electron transport rate, relative, standard deviation; Nitrogen, organic, particulate; Nitrogen, organic, particulate, per cell; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate organic carbon, production, standard deviation; Particulate organic nitrogen, standard deviation; Particulate organic nitrogen production, standard deviation; pH; pH, standard deviation; Phytoplankton; Primary production/Photosynthesis; Production of particulate organic carbon; Production of particulate organic nitrogen; Registration number of species; Salinity; Single species; Species; Temperature, water; Thalassiosira pseudonana; Time of day; Total carbon fixation per cell per hour; Treatment; Type; Uniform resource locator/link to reference
Type:
Dataset
Format:
text/tab-separated-values, 2936 data points
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