Publication Date:
2024-03-15
Description:
Fish farming in coastal areas has become an important source of food to support the world's increasing population. However, intensive and unregulated mariculture activities have contributed to changing seawater carbonate chemistry through the production of high levels of respiratory CO2. This additional CO2, i.e. in addition to atmospheric inputs, intensifies the effects of global ocean acidification resulting in localized extreme low pH levels. Marine calcifying macroalgae are susceptible to such changes due to their CaCO3 skeleton. Their physiological response to CO2-driven acidification is dependent on their carbon physiology. In this study, we used the pH drift experiment to determine the capability of 9 calcifying macroalgae to use one or more inorganic carbon (Ci) species. From the 9 species, we selected the rhodolith Sporolithon sp. as a model organism to investigate the long-term effects of extreme low pH on the physiology and biochemistry of calcifying macroalgae. Samples were incubated under two pH treatments (pH 7.9 = ambient and pH 7.5 = extreme acidification) in a temperature-controlled (26 ± 0.02 °C) room provided with saturating light intensity (98.3 ± 2.50 μmol photons/m**2/s). After the experimental treatment period (40 d), growth rate, calcification rate, nutrient uptake rate, organic content, skeletal CO3-2, pigments, and tissue C, N and P of Sporolithon samples were compared. The pH drift experiment revealed species-specific Ci use mechanisms, even between congenerics, among tropical calcifying macroalgae. Furthermore, long-term extreme low pH significantly reduced the growth rate, calcification rate and skeletal CO3-2 content by 79%, 66% and 18%, respectively. On the other hand, nutrient uptake rates, organic matter, pigments and tissue C, N and P were not affected by the low pH treatments. Our results suggest that the rhodolith Sporolithon sp. is susceptible to the negative effects of extreme low pH resulting from intensive mariculture-driven coastal acidification.
Keywords:
Alkalinity, total; Alkalinity, total, standard error; Allophycocyanin; Allophycocyanin, standard error; Ammonium uptake rate; Ammonium uptake rate, standard error; Aragonite saturation state; Benthos; Bicarbonate ion; Bicarbonate ion, standard error; Biomass/Abundance/Elemental composition; Bottles or small containers/Aquaria (〈20 L); 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; Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard error; Carbon, standard error; Carbon/Nitrogen ratio; Carbon/Nitrogen ratio, standard error; Carbon/Phosphorus ratio; Carbon/Phosphorus ratio, standard error; Carbonate ion; Carbonate ion, standard error; Carbonate system computation flag; Carbon dioxide; Carbon dioxide, standard error; Chlorophyll a; Chlorophyll a, standard error; Chlorophyll d; Chlorophyll d, standard error; Coast and continental shelf; Dos_Hermanos; EXP; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth; Growth, relative, standard error; Growth/Morphology; Inorganic matter; Inorganic matter, standard error; Laboratory experiment; Macroalgae; Nitrate uptake rate; Nitrate uptake rate, standard error; Nitrite uptake rate; Nitrite uptake rate, standard error; Nitrogen; Nitrogen, standard error; Nitrogen/Phosphorus ratio; Nitrogen/Phosphorus ratio, standard error; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Organic matter; Organic matter, standard error; 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; Phosphate uptake rate; Phosphate uptake rate, standard error; Phosphorus; Phosphorus, standard error; Phycocyanin; Phycocyanin, standard error; Phycoerythrin; Phycoerythrin, standard error; Plantae; Potentiometric; Potentiometric titration; Rhodophyta; Salinity; Salinity, standard error; Single species; Skeleton; Skeleton, standard error; Species; Sporolithon sp.; Temperature, water; Temperature, water, standard error; Treatment; Tropical; Type
Type:
Dataset
Format:
text/tab-separated-values, 144 data points
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