Publication Date:
2024-03-15
Description:
Light affects iron (Fe) growth requirements in marine phytoplankton while CO2 can influence energy allocation and light sensitivity. Therefore, ongoing increases in seawater CO2 concentrations could impact the growth of Fe- and light-limited phytoplankton. In this study, Phaeodactylum tricornutum was used as a model diatom to examine the interactive effects of Fe, light, and CO2 on photosynthesis, growth, and protein expression in marine phytoplankton. Low concentration of biologically available inorganic iron (Fe) and low-light intensity decreased specific rates of carbon (C)-fixation and growth, and the two together had an even greater effect, indicating a co-limitation. Increased partial pressure of CO2 from its current value (400 μatm) to 750 μatm had no effect at growth sufficient levels of Fe and light, but increased C-fixation and growth rate under Fe or light limitation, and had an even greater effect in Fe and light co-limited cells. The results suggest that ongoing increases in CO2 may increase C-fixation rates in Fe- and light-limited and co-limited regions, which cover at least 30% of the ocean. Measurements of photosynthetic proteins in photosystems II and I, and transcripts of proteins involved in CO2 concentrating mechanisms (CCMs), photorespiration, and antioxidant protection, suggest that the benefit of increased CO2 in the Fe- and light-limited cells was from a downregulation of CCMs and resultant decreased demands for energy supplied from photosynthesis, and from decreased rates of photorespiration, which consumes photosynthetically produced ATP and NADPH. A decrease in oxidative stress with increased CO2 also contributed.
Keywords:
Alkalinity, total; Alkalinity, total, standard deviation; Aragonite saturation state; Bicarbonate ion; Biomass/Abundance/Elemental composition; 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 system computation flag; Carbon dioxide; Carbon fixation rate; Carbon fixation rate, standard deviation; Cell iron/carbon ratio; Cell iron/carbon ratio, standard deviation; Chromista; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gene expression (incl. proteomics); Growth/Morphology; Growth Iron use efficiency; Growth Iron use efficiency, standard deviation; Growth rate; Growth rate, standard deviation; Iron, dissolved, inorganic; Iron uptake rate; Iron uptake rate, standard deviation; Irradiance; Laboratory experiment; Laboratory strains; Light; Micro-nutrients; mRNA copy numbers ratio; mRNA copy numbers ratio, standard deviation; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Other metabolic rates; Other studied parameter or process; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Phaeodactylum tricornutum; Photosynthetic Iron use efficiency; Photosynthetic Iron use efficiency, standard deviation; Photosynthetic protein, PsbA, standard deviation; Photosynthetic protein, PsbC, standard deviation; Phytoplankton; Primary production/Photosynthesis; PsaC protein; PsbA protein; PsbA protein/PsaC protein ratio; PsbA protein/PsaC protein ratio, standard deviation; Registration number of species; Salinity; Single species; Species; Spectrophotometric; Temperature, water; Treatment; Treatment: partial pressure of carbon dioxide; Type; Uniform resource locator/link to reference
Type:
Dataset
Format:
text/tab-separated-values, 456 data points
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