Seawater carbonate chemistry and UVR-induced inhibition of photosynthetic light reactions and growth in an intertidal red macroalga

• Main Authors: Zhang, Di, Xu, Juntian, Bao, Menglin, Beer, Sven, Yan, Dong, Beardall, John, Gao, Kunshan
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2020
• Subjects: Benthos; Bottles or small containers/Aquaria <20 L; Coast and continental shelf; Growth/Morphology; Laboratory experiment; Light; Macroalgae; North Pacific; Plantae; Primary production/Photosynthesis; Pyropia yezoensis; Rhodophyta; Single species; Temperate; Type; Species; Registration number of species; Uniform resource locator/link to reference; Treatment; Growth rate; Growth rate, standard deviation; Carbon dioxide assimilation rate per area; Carbon dioxide assimilation rate, standard deviation; 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; Effective quantum yield; Effective quantum yield, standard deviation; Non photochemical quenching; Non photochemical quenching, standard deviation; Ultraviolet absorbing compounds; Ultraviolet absorbing compounds, standard deviation; Ultraviolet radiation-induced inhibition; Ultraviolet radiation-induced inhibition, standard deviation; Temperature, water; Temperature, water, standard deviation; Salinity; pH; pH, standard deviation; Alkalinity, total; Alkalinity, total, standard deviation; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard deviation; Bicarbonate ion; Bicarbonate ion, standard deviation; Carbonate ion; Carbonate ion, standard deviation; Carbon dioxide; Carbon dioxide, standard deviation; Carbonate system computation flag; Fugacity of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air; Aragonite saturation state; Calcite saturation state; Experiment; Potentiometric titration; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Psi; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.927308; https://doi.pangaea.de/10.1594/PANGAEA.927308

The commercially important red macroalga Pyropia (formerly Porphyra) yezoensis is, in its natural intertidal environment, subjected to high levels of both photosynthetically active and ultraviolet radiation (PAR and UVR, respectively). In the present work, we investigated the effects of a plausibly increased global CO2 concentration on quantum yields of photosystems II (PSII) and I (PSI), as well as photosynthetic and growth rates of P. yezoensis grown under natural solar irradiance regimes with or without the presence of UV-A and/or UV-B. Our results showed that the high-CO2 treatment (1000 μbar, which also caused a drop of 0.3 pH units in the seawater) significantly increased both CO2 assimilation rates (by 35%) and growth (by 18%), as compared with ambient air of 400 μbar CO2. The inhibition of growth by UV-A (by 26%) was reduced to 15% by high-CO2 concentration, while the inhibition by UV-B remained at ~6% under both CO2 concentrations. Homologous results were also found for the maximal relative photosynthetic electron transport rates (rETRmax), the maximum quantum yield of PSII (Fv/Fm), as well as the midday decrease in effective quantum yield of PSII (YII) and concomitant increased non-photochemical quenching (NPQ). A two-way ANOVA analysis showed an interaction between CO2 concentration and irradiance quality, reflecting that UVR-induced inhibition of both growth and YII were alleviated under the high-CO2 treatment. Contrary to PSII, the effective quantum yield of PSI (YI) showed higher values under high-CO2 condition, and was not significantly affected by the presence of UVR, indicating that it was well protected from this radiation. Both the elevated CO2 concentration and presence of UVR significantly induced UV-absorbing compounds. These results suggest that future increasing CO2 conditions will be beneficial for photosynthesis and growth of P. yezoensis even if UVR should remain at high levels. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2020) 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 2021-01-25.