Publication Date:
2024-04-03
Description:
We examined the combined effects of light and pCO2 on growth, CO2-fixation and N2-fixation rates by strains of the unicellular marine N2-fixing cyanobacterium Crocosphaera watsonii with small (WH0401) and large (WH0402) cells that were isolated from the western tropical Atlantic Ocean. In low-pCO2-acclimated cultures (190 ppm) of WH0401, growth, CO2-fixation and N2-fixation rates were significantly lower than those in cultures acclimated to higher (present-day 385 ppm, or future 750 ppm) pCO2 treatments. Growth rates were not significantly different, however, in low-pCO2-acclimated cultures of WH0402 in comparison with higher pCO2 treatments. Unlike previous reports for C. watsonii (strain WH8501), N2-fixation rates did not increase further in cultures of WH0401 or WH0402 when acclimated to 750 ppm relative to those maintained at present-day pCO2. Both light and pCO2 had a significant negative effect on gross : net N2-fixation rates in WH0402 and trends were similar in WH0401, implying that retention of fixed N was enhanced under elevated light and pCO2. These data, along with previously reported results, suggest that C. watsonii may have wide-ranging, strain-specific responses to changing light and pCO2, emphasizing the need for examining the effects of global change on a range of isolates within this biogeochemically important genus. In general, however, our data suggest that cellular N retention and CO2-fixation rates of C. watsonii may be positively affected by elevated light and pCO2 within the next 100 years, potentially increasing trophic transfer efficiency of C and N and thereby facilitating uptake of atmospheric carbon by the marine biota.
Keywords:
15N2-tracer method; Alkalinity, total; Aragonite saturation state; Bacteria; Bicarbonate ion; 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, photosynthetic; Coulometric titration; Crocosphaera watsonii; Cyanobacteria; Diameter; Diameter, standard error; Figure; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Growth rate, standard deviation; Irradiance; Laboratory experiment; Laboratory strains; Light; Nitrogen, particulate, accumulation, per cell; Nitrogen, particulate, accumulation, standard deviation; Nitrogen fixation rate; Nitrogen fixation rate, gross/nitrogen fixation rate, netto ratio; Nitrogen fixation rate, gross/nitrogen fixation rate, netto ratio, standard deviation; Nitrogen fixation rate, gross/particulate nitrogen, netto, accumulation rate ratio; Nitrogen fixation rate, gross/particulate nitrogen, netto, accumulation rate ratio, standard deviation; Nitrogen fixation rate, per cell; Nitrogen fixation rate, standard deviation; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Other metabolic rates; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Photosynthetic carbon fixation rate, standard deviation; Photosynthetic carbon fixation rate per cell; Phytoplankton; Potentiometric; Primary production/Photosynthesis; Salinity; Single species; Species; Strain; Temperature, water
Type:
Dataset
Format:
text/tab-separated-values, 1043 data points
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