Publication Date:
2024-03-15
Description:
Along with increasing oceanic CO2 concentrations, enhanced stratification constrains phytoplankton to shallower upper mixed layers with altered light regimes and nutrient concentrations. Here, we investigate the effects of elevated pCO2 in combination with light or nitrogen-limitation on 13C fractionation (epsilon p) in four dinoflagellate species. We cultured Gonyaulax spinifera and Protoceratium reticulatum in dilute batches under low-light (LL) and high-light (HL) conditions, and grew Alexandrium fundyense and Scrippsiella trochoidea in nitrogen-limited continuous cultures (LN) and nitrogen-replete batches (HN). The observed CO2-dependency of epsilon p remained unaffected by the availability of light for both G. spinifera and P. reticulatum, though at HL epsilon p was consistently lower by about 2.7 per mil over the tested CO2 range for P. reticulatum. This may reflect increased uptake of (13C-enriched) bicarbonate fueled by increased ATP production under HL conditions. The observed CO2-dependency of epsilon p disappeared under LN conditions in both A. fundyense and S. trochoidea. The generally higher epsilon p under LN may be associated with lower organic carbon production rates and/or higher ATP:NADPH ratios. CO2-dependent epsilon p under non-limiting conditions has been observed in several dinoflagellate species, showing potential for a new CO2-proxy. Our results however demonstrate that light- and nitrogen-limitation also affect epsilon p, thereby illustrating the need to carefully consider prevailing environmental conditions.
Keywords:
Alexandrium fundyense; 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; Carbon, organic, particulate, per cell; Carbon, organic, particulate, standard deviation; Carbon, organic, particulate/Nitrogen, organic, particulate ratio; Carbon, organic, particulate/Nitrogen, organic, particulate ratio, standard deviation; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard deviation; Chlorophyll a, standard deviation; Chlorophyll a per cell; Chromista; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gonyaulax spinifera; Growth/Morphology; Growth rate; Growth rate, standard deviation; Isotopic fractionation, during photosynthis; Isotopic fractionation, during photosynthis, standard deviation; Laboratory experiment; Laboratory strains; Light; Macro-nutrients; Myzozoa; Not applicable; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Pelagos; pH; pH, standard deviation; Phytoplankton; Potentiometric; Potentiometric titration; Primary production/Photosynthesis; Protoceratium reticulatum; Registration number of species; Salinity; Scrippsiella trochoidea; Single species; Species; Temperature, water; Treatment; Type; Uniform resource locator/link to reference
Type:
Dataset
Format:
text/tab-separated-values, 1008 data points
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