Publication Date:
2024-07-06
Description:
Ocean acidification (OA) has important implications for the persistence of coral reef ecosystems, due to potentially negative effects on biomineralization. Many coral reefs are dynamic with respect to carbonate chemistry, and experience fluctuations in pCO2 that exceed OA projections for the near future. To understand the influence of dynamic pCO2 on an important reef calcifier, we tested the response of the crustose coralline alga Porolithon onkodes to oscillating pCO2. Individuals were exposed to ambient (400 µatm), high (660 µatm), or variable pCO2 (oscillating between 400/660 µatm) treatments for 14 days. To explore the potential for coralline acclimatization, we collected individuals from low and high pCO2 variability sites (upstream and downstream respectively) on a back reef characterized by unidirectional water flow in Moorea, French Polynesia. We quantified the effects of treatment on algal calcification by measuring the change in buoyant weight, and on algal metabolism by conducting sealed incubations to measure rates of photosynthesis and respiration. Net photosynthesis was higher in the ambient treatment than the variable treatment, regardless of habitat origin, and there was no effect on respiration or gross photosynthesis. Exposure to high pCO2 decreased P. onkodes calcification by 〉70%, regardless of the original habitat. In the variable treatment, corallines from the high variability habitat calcified 42% more than corallines from the low variability habitat. The significance of the original habitat for the coralline calcification response to variable, high pCO2 indicates that individuals existing in dynamic pCO2 habitats may be acclimatized to OA within the scope of in situ variability. These results highlight the importance of accounting for natural pCO2 variability in OA manipulations, and provide insight into the potential for plasticity in habitat and species-specific responses to changing ocean chemistry.
Keywords:
Alkalinity, total; Alkalinity, total, standard error; Aragonite saturation state; Aragonite saturation state, standard error; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcification rate, standard error; Calcification rate of calcium carbonate; Calcite saturation state; Calcite saturation state, standard error; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Containers and aquaria (20-1000 L or 〈 1 m**2); Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gross photosynthesis rate, oxygen; Gross photosynthesis rate, oxygen, standard error; Irradiance; Irradiance, standard error; Laboratory experiment; Macroalgae; Net photosynthesis rate, oxygen; Net photosynthesis rate, oxygen, 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, standard error; Plantae; Porolithon onkodes; Potentiometric titration; Primary production/Photosynthesis; Respiration; Respiration rate, oxygen; Respiration rate, oxygen, standard error; Rhodophyta; Salinity; Salinity, standard error; Single species; South Pacific; Species; Spectrophotometric; Temperature, water; Temperature, water, standard error; Treatment; Tropical
Type:
Dataset
Format:
text/tab-separated-values, 264 data points
Permalink
