Publication Date:
2024-05-27
Description:
Climate change is expected to bring about alterations in the marine physical and chemical environment that will induce changes in the concentration of dissolved CO2 and in nutrient availability. These in turn are expected to affect the physiological performance of phytoplankton. In order to learn how phytoplankton respond to the predicted scenario of increased CO2 and decreased nitrogen in the surface mixed layer, we investigated the diatom Phaeodactylum tricornutum as a model organism. The cells were cultured in both low CO2 (390 µatm) and high CO2 (1000 µatm) conditions at limiting (10 µmol/L) or enriched (110 µmol/L) nitrate concentrations. Our study shows that nitrogen limitation resulted in significant decreases in cell size, pigmentation, growth rate and effective quantum yield of Phaeodactylum tricornutum, but these parameters were not affected by enhanced dissolved CO2 and lowered pH. However, increased CO2 concentration induced higher rETRmax and higher dark respiration rates and decreased the CO2 or dissolved inorganic carbon (DIC) affinity for electron transfer (shown by higher values for K1/2 DIC or K1/2 CO2). Furthermore, the elemental stoichiometry (carbon to nitrogen ratio) was raised under high CO2 conditions in both nitrogen limited and nitrogen replete conditions, with the ratio in the high CO2 and low nitrate grown cells being higher by 45% compared to that in the low CO2 and nitrate replete grown ones. Our results suggest that while nitrogen limitation had a greater effect than ocean acidification, the combined effects of both factors could act synergistically to affect marine diatoms and related biogeochemical cycles in future oceans.
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, reciprocal of photosynthetic affinity value; Carbon, inorganic, dissolved, reciprocal of photosynthetic affinity value, standard deviation; Carbon, inorganic, dissolved, standard deviation; Carbon, organic, particulate, per cell; Carbonate ion; Carbonate ion, standard deviation; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, reciprocal of photosynthetic affinity value; Carbon dioxide, reciprocal of photosynthetic affinity value, standard deviation; Carbon dioxide, standard deviation; Carotenoids, standard deviation; Carotenoids per cell; Cell biovolume; Cell biovolume, standard deviation; Cell counts, percent of total; Cell counts, standard deviation; Cell size; Cell size, standard deviation; Chlorophyll a, standard deviation; Chlorophyll a per cell; Chlorophyll c, standard deviation; Chlorophyll c per cell; Chromista; Coulometric titration; Effective quantum yield; Effective quantum yield, standard deviation; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Growth rate; Growth rate, standard deviation; Identification; Laboratory experiment; Laboratory strains; Macro-nutrients; Maximal electron transport rate, relative; Maximal electron transport rate, relative, standard deviation; Maximum photochemical quantum yield of photosystem II; Maximum photochemical quantum yield of photosystem II, standard deviation; Nitrogen, organic, particulate, per cell; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; Partial pressure of carbon dioxide, standard deviation; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Particulate organic carbon content per cell, standard deviation; Particulate organic nitrogen per cell, standard deviation; pH; pH, standard deviation; Phaeodactylum tricornutum; Photochemical efficiency; Photochemical efficiency, standard deviation; Phytoplankton; Potentiometric; Primary production/Photosynthesis; Respiration; Respiration rate, oxygen, per cell; Respiration rate, oxygen, per chlorophyll a; Respiration rate, oxygen, standard deviation; Salinity; Single species; Species; Spectrophotometric; Temperature, water; Treatment
Type:
Dataset
Format:
text/tab-separated-values, 29292 data points
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