Publication Date:
2024-03-15
Description:
Despite the heightened awareness of ocean acidification (OA) effects on marine organisms, few studies empirically juxtapose biological responses to CO2 manipulations across functionally distinct primary producers, particularly benthic algae. Algal responses to OA may vary because increasing CO2 has the potential to fertilize photosynthesis but impair biomineralization. Using a series of repeated experiments on Palmyra Atoll, simulated OA effects were tested across a suite of ecologically important coral reef algae, including five fleshy and six calcareous species. Growth, calcification and photophysiology were measured for each species independently and metrics were combined from each experiment using a meta-analysis to examine overall trends across functional groups categorized as fleshy, upright calcareous, and crustose coralline algae (CCA). The magnitude of the effect of OA on algal growth response varied by species, but the direction was consistent within functional groups. Exposure to OA conditions generally enhanced growth in fleshy macroalgae, reduced net calcification in upright calcareous algae, and caused net dissolution in CCA. Additionally, three of the five fleshy seaweeds tested became reproductive upon exposure to OA conditions. There was no consistent effect of OA on algal photophysiology. Our study provides experimental evidence to support the hypothesis that OA will reduce the ability of calcareous algae to biomineralize. Further, we show that CO2 enrichment either will stimulate population or somatic growth in some species of fleshy macroalgae. Thus, our results suggest that projected OA conditions may favor non-calcifying algae and influence the relative dominance of fleshy macroalgae on reefs, perpetuating or exacerbating existing shifts in reef community structure.
Keywords:
Acanthophora spicifera; Alkalinity, total; Alkalinity, total, standard error; Aragonite saturation state; Aragonite saturation state, standard error; Avrainvillea amadelpha; Benthos; Bicarbonate ion; Bicarbonate ion, standard error; Bottles or small containers/Aquaria (〈20 L); Calcite saturation state; Calcite saturation state, standard error; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbon, inorganic, dissolved, standard error; Carbonate ion; Carbonate ion, standard error; Carbonate system computation flag; Carbon dioxide; Caulerpa serrulata; Chlorophyta; Coast and continental shelf; Coulometric titration; Dichotomaria marginata; Dictyota bartayresiana; Experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Galaxaura rugosa; Growth/Morphology; Growth rate; Growth rate, standard error; Halimeda opuntia; Halimeda taenicola; Hypnea pannosa; Laboratory experiment; Lithophyllum prototypum; Lithophyllum sp.; Macroalgae; Maximal electron transport rate, relative; Maximal electron transport rate, relative, standard error; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Ochrophyta; 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; Photoinhibition; Photoinhibition, standard error; Photosynthetic efficiency; Photosynthetic efficiency, standard error; Plantae; Potentiometric titration; Primary production/Photosynthesis; Replicates; Rhodophyta; Run Number; Salinity; Salinity, standard error; Single species; Species; Table; Temperature, water; Treatment; Tropical
Type:
Dataset
Format:
text/tab-separated-values, 2271 data points
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