Publication Date:
2024-03-15
Description:
Experimentally elevated pCO2 and the associated pH drop are known to differentially affect many aspects of the physiology of diatoms under different environmental conditions or in different regions. However, contrasting responses to elevated pCO2 in the dark and light periods of a diel cycle have not been documented. By growing the model diatom Phaeodactylum tricornutum under 3 light levels and 2 different CO2 concentrations, we found that the elevated pCO2/pH drop projected for future ocean acidification reduced the diatom's growth rate by 8–25% during the night period but increased it by up to 9–21% in the light period, resulting in insignificant changes in growth over the diel cycle under the three different light levels. The elevated pCO2 increased the respiration rates irrespective of growth light levels and light or dark periods and enhanced its photosynthetic performance during daytime. With prolonged exposure to complete darkness, simulating the sinking process in the dark zones of the ocean, the growth rates decreased faster under elevated pCO2, along with a faster decline in quantum yield and cell size. Our results suggest that elevated pCO2 enhances the diatom's respiratory energy supplies to cope with acidic stress during the night period but enhances its death rate when the cells sink to dark regions of the oceans below the photic zone, with implications for a possible acidification-induced reduction in vertical transport of organic carbon.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Bicarbonate ion; Bicarbonate ion, standard deviation; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Carotenoids, standard deviation; Carotenoids/Chlorophyll a ratio; Carotenoids/Chlorophyll a ratio, standard deviation; Carotenoids per cell; Cell, diameter; Cell, diameter, standard deviation; Chlorophyll a, standard deviation; Chlorophyll a per cell; Chromista; Effective photochemical quantum yield; Effective photochemical quantum yield, standard deviation; Electron transport rate, relative; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Laboratory experiment; Laboratory strains; Light; Light mode; Maximum quantum yield of photosystem II; Maximum quantum yield of photosystem II, standard deviation; Net photosynthesis rate, oxygen, per cell; Net photosynthesis rate, standard deviation; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Phaeodactylum tricornutum; Phytoplankton; Primary production/Photosynthesis; Ratio; Ratio, standard deviation; Registration number of species; Respiration; Respiration rate, oxygen, per cell; Respiration rate, oxygen, standard deviation; Salinity; Single species; Species; Temperature, water; Time in hours; Treatment; Type; Uniform resource locator/link to reference
Type:
Dataset
Format:
text/tab-separated-values, 3030 data points
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