Publication Date:
2024-03-15
Description:
We measured the relationship between CO2-induced seawater acidification, photo-physiological performance and intracellular pH (pHi) in a model cnidarian-dinoflagellate symbiosis - the sea anemone Aiptasia sp. -under ambient (289.94 ± 12.54 µatm), intermediate (687.40 ± 25.10 µatm) and high (1459.92 ± 65.51 µatm) CO2 conditions. These treatments represented current CO2 levels, in addition to CO2 stabilisation scenarios IV and VI provided by the Intergovernmental Panel on Climate Change (IPCC). Anemones were exposed to each treatment for two months and sampled at regular intervals. At each time-point we measured a series of physiological responses: maximum dark-adapted fluorescent yield of PSII (Fv/Fm), gross photosynthetic rate, respiration rate, symbiont population density, and light-adapted pHi of both the dinoflagellate symbiont and isolated host anemone cell. We observed increases in all but one photo-physiological parameter (Pgross:R ratio). At the cellular level, increases in light-adapted symbiont pHi were observed under both intermediate and high CO2 treatments, relative to control conditions (pHi 7.35 and 7.46 versus pHi 7.25, respectively). The response of light-adapted host pHi was more complex, however, with no change observed under the intermediate CO2 treatment, but a 0.3 pH-unit increase under the high CO2 treatment (pHi 7.19 and 7.48, respectively). This difference is likely a result of a disproportionate increase in photosynthesis relative to respiration at the higher CO2 concentration. Our results suggest that, rather than causing cellular acidosis, the addition of CO2 will enhance photosynthetic performance, enabling both the symbiont and host cell to withstand predicted ocean acidification scenarios.
Keywords:
Aiptasia pulchella; Alkalinity, total; Alkalinity, total, standard error; Animalia; Aragonite saturation state; Benthic animals; Benthos; Bicarbonate ion; Bicarbonate ion, standard error; 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; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cnidaria; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gross photosynthesis/respiration ratio; Gross photosynthesis/respiration ratio, standard error; Gross photosynthesis rate, oxygen; Gross photosynthesis rate, oxygen, per cell; Gross photosynthesis rate, oxygen, standard error; Incubation duration; Laboratory experiment; Laboratory strains; Maximum photochemical quantum yield of photosystem II; Maximum photochemical quantum yield of photosystem II, standard error; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); Partial pressure of carbon dioxide (water) at sea surface temperature (wet air), standard error; pH; pH, intracellular; pH, intracellular, standard error; pH, standard error; Potentiometric; Primary production/Photosynthesis; Respiration; Respiration rate, oxygen; Respiration rate, oxygen, standard error; Salinity; Single species; South Pacific; Species; Symbiont cell density; Symbiont cell density, standard error; Temperature, water; Temperature, water, standard error
Type:
Dataset
Format:
text/tab-separated-values, 702 data points
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