Publication Date:
2024-03-15
Description:
Iron availability in seawater, namely the concentration of dissolved inorganic iron ([Fe']), is affected by changes in pH. Such changes in the availability of iron should be taken into account when investigating the effects of ocean acidification on phytoplankton ecophysiology because iron plays a key role in phytoplankton metabolism. However, changes in iron availability in response to changes in ocean acidity are difficult to quantify specifically using natural seawater because these factors change simultaneously. In the present study, the availability of iron and carbonate chemistry were manipulated individually and simultaneously in the laboratory to examine the effect of each factor on phytoplankton ecophysiology. The effects of various pCO2 conditions (390, 600, and 800 µatm) on the growth, cell size, and elemental stoichiometry (carbon [C], nitrogen [N], phosphorus [P], and silicon [Si]) of the diatom Thalassiosira weissflogii under high iron ([Fe'] = 240 pmol/l) and low iron ([Fe'] = 24 pmol/l) conditions were investigated. Cell volume decreased with increasing pCO2, whereas intracellular C, N, and P concentrations increased with increasing pCO2 only under high iron conditions. Si:C, Si:N, and Si:P ratios decreased with increasing pCO2. It reflects higher production of net C, N, and P with no corresponding change in net Si production under high pCO2 and high iron conditions. In contrast, significant linear relationships between measured parameters and pCO2 were rarely detected under low iron conditions. We conclude that the increasing CO2 levels could affect on the biogeochemical cycling of bioelements selectively under the iron-replete conditions in the coastal ecosystems.
Keywords:
Alkalinity, total; Aragonite saturation state; Bicarbonate ion; Biogenic silica; Biogenic silica, per cell; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, intracellular; Carbon, organic, particulate; Carbon, organic, particulate, per cell; Carbon/Nitrogen ratio; Carbon/Phosphorus ratio; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cell biovolume; Cell density; Chlorophyll a; Chlorophyll a, intracellular; Chlorophyll a per cell; Chlorophyll a production per cell; Chromista; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Iron, dissolved, inorganic; Laboratory experiment; Laboratory strains; Micro-nutrients; Net nitrogen production rate; Net phosphorus production; Net silicon production; Nitrogen, intracellular; Nitrogen, particulate; Nitrogen, particulate, per cell; Nitrogen/Phosphorus ratio; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate organic carbon production per cell; Pelagos; pH; Phosphorus, intracellular; Phosphorus, organic, particulate, per cell; Phosphorus, particulate; Phytoplankton; Primary production/Photosynthesis; Registration number of species; Salinity; Silicon/Carbon, molar ratio; Silicon/Nitrogen, molar ratio; Silicon/Phosphorus ratio; Silicon per surface area; Single species; Species; Surface area; Temperature, water; Thalassiosira weissflogii; Time in days; Treatment; Type; Uniform resource locator/link to reference
Type:
Dataset
Format:
text/tab-separated-values, 1179 data points
Permalink