Seawater carbonate chemistry and growth and chlorophyll, photochemical parameters, carbon fixation of diatom Phaeodactylum tricornutum, supplement to: Liu, Nana; Beardall, John; Gao, Kunshan (2017): Elevated CO2 and associated seawater chemistry do not benefit a model diatom grown with increased availability of light. Aquatic Microbial Ecology, 79(2), 137-147

• Main Authors: Liu, Nana, Beardall, John, Gao, Kunshan
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2017
• Subjects: Bottles or small containers/Aquaria <20 L; Chromista; Growth/Morphology; Laboratory experiment; Laboratory strains; Light; Not applicable; Pelagos; Phaeodactylum tricornutum; Phytoplankton; Primary production/Photosynthesis; Single species; Type; Species; Registration number of species; Uniform resource locator/link to reference; Partial pressure of carbon dioxide water at sea surface temperature wet air; Treatment; Identification; Growth rate; Maximum photochemical quantum yield of photosystem II; Time in seconds; Effective quantum yield; Light saturation point; Maximal electron transport rate, relative; Light capturing capacity; Cumulative carbon fixation per cell; Initial slope of photosynthesis vs dissolved inorganic carbon; Light saturated maximum photosynthetic rate per cell; Carbon, inorganic, dissolved, intracellular pool; Factor; Temperature, water; Salinity; pH; Alkalinity, total; Carbon, inorganic, dissolved; Bicarbonate ion; Carbonate ion; Carbon dioxide; Carbonate system computation flag; Fugacity of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.900658; https://doi.pangaea.de/10.1594/PANGAEA.900658

Elevated CO2 is leading to a decrease in pH in marine environments (ocean acidification [OA]), altering marine carbonate chemistry. OA can influence the metabolism of many marine organisms; however, no consensus has been reached on its effects on algal photosynthetic carbon fixation and primary production. Here, we found that when the diatom Phaeodactylum tricornutum was grown under different pCO2 levels, it showed different responses to elevated pCO2 levels under growth-limiting (20 µmol photons/m**2/s, LL) compared with growth-saturating (200 µmol photons/m**2/s, HL) light levels. With pCO2 increased up to 950 µatm, growth rates and primary productivity increased, but in the HL cells, these parameters decreased significantly at higher concentrations up to 5000 µatm, while no difference in growth was observed with pCO2 for the LL cells. Elevated CO2 concentrations reduced the size of the intracellular dissolved inorganic carbon (DIC) pool by 81% and 60% under the LL and HL levels, respectively, with the corresponding photosynthetic affinity for DIC decreasing by 48% and 55%. Little photoinhibition was observed across all treatments. These results suggest that the decreased growth rates under higher CO2 levels in the HL cells were most likely due to acid stress. Low energy demand of growth and energy saving from the down-regulation of the CO2 concentrating mechanisms (CCM) minimized the effects of acid stress on the growth of the LL cells. These findings imply that OA treatment, except for down-regulating CCM, caused stress on the diatom, reflected in diminished C assimilation and growth rates. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2016) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2019-04-25.