Publication Date:
2024-03-15
Description:
Biological mediation of carbonate dissolution represents a fundamental component of the destructive forces acting on coral reef ecosystems. Whereas ocean acidification can increase dissolution of carbonate substrates, the combined impact of ocean acidification and warming on the microbioerosion of coral skeletons remains unknown. Here, we exposed skeletons of the reef-building corals, Porites cylindrica and Isopora cuneata, to present-day (Control: 400 µatm - 24 °C) and future pCO2-temperature scenarios projected for the end of the century (Medium: +230 µatm - +2 °C; High: +610 µatm - +4 °C). Skeletons were also subjected to permanent darkness with initial sodium hypochlorite incubation, and natural light without sodium hypochlorite incubation to isolate the environmental effect of acidic seawater (i.e., Omega aragonite 〈1) from the biological effect of photosynthetic microborers. Our results indicated that skeletal dissolution is predominantly driven by photosynthetic microborers, as samples held in the dark did not decalcify. In contrast, dissolution of skeletons exposed to light increased under elevated pCO2-temperature scenarios, with P. cylindrica experiencing higher dissolution rates per month (89%) than I. cuneata (46%) in the high treatment relative to control. The effects of future pCO2-temperature scenarios on the structure of endolithic communities were only identified in P. cylindrica and were mostly associated with a higher abundance of the green algae Ostreobium spp. Enhanced skeletal dissolution was also associated with increased endolithic biomass and respiration under elevated pCO2-temperature scenarios. Our results suggest that future projections of ocean acidification and warming will lead to increased rates of microbioerosion. However, the magnitude of bioerosion responses may depend on the structural properties of coral skeletons, with a range of implications for reef carbonate losses under warmer and more acidic oceans.
Keywords:
Abundance; Abundance, standard error; Alkalinity, total; Alkalinity, total, standard error; Animalia; Aragonite saturation state; Aragonite saturation state, standard error; Benthic animals; Benthos; Bicarbonate ion; Bicarbonate ion, standard error; Biomass; Biomass, standard error; Bottles or small containers/Aquaria (〈20 L); Buoyant weighing technique according to Davies (1989); Calcification/Dissolution; Calcite saturation state; Calculated using CO2SYS; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate ion, standard error; Carbonate system computation flag; Carbon dioxide; Cnidaria; Coast and continental shelf; Dissolution/calcification; Dissolution/calcification, standard error; Dissolution rate of calcium carbonate; Distance; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Great_Barrier_Reef; Great Barrier Reef, Australia; Hyella sp.; Identification; Irradiance; Isopora cuneata; Laboratory experiment; Loss of ignition analysis; Mastigocoleus testarum; OA-ICC; Ocean Acidification International Coordination Centre; Oscillatoria sp.; Ostreobium sp.; 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; Plectonema terebrans; Porites cylindrica; Potentiometric titration; Respiration; Respiration rate, oxygen; Salinity; Salinity, standard error; Single species; South Pacific; Species; Spirulina sp.; Temperate; Temperature; Temperature, water; Temperature, water, standard error; Treatment
Type:
Dataset
Format:
text/tab-separated-values, 9021 data points
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