Publication Date:
2024-03-15
Description:
The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT(8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT(7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification.
Keywords:
AA; Alkalinity, Gran titration (Gran, 1950); Alkalinity, total; Alkalinity, total, standard deviation; Animalia; Aragonite saturation state; Autoanalyzer; Benthic animals; Benthos; Bicarbonate ion; Biomass/Abundance/Elemental composition; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon, inorganic, dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cnidaria; Containers and aquaria (20-1000 L or 〈 1 m**2); Electron transport rate of photosystem II; EPOCA; EUR-OCEANS; European network of excellence for Ocean Ecosystems Analysis; European Project on Ocean Acidification; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Laboratory experiment; Laboratory strains; Light:Dark cycle; Maximum photochemical quantum yield of photosystem II; Nutrient uptake rate, per chlorophyll; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen evolution, per chlorophyll a; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; pH meter (Metrohm, 826 pH mobile); Primary production/Photosynthesis; pulse-amplitude-modulated chlorophyll fluorometry (diving PAM, Waltz, Germany); Radiation, photosynthetically active; Red Sea; Salinity; see reference(s); Single species; Spectrofluorometry; Spectrophotometry; Stylophora pistillata; Stylophora pistillata, chlorophyll; Stylophora pistillata, protein content; Stylophora pistillata, zooxanthellate cell density; Temperature; Temperature, water
Type:
Dataset
Format:
text/tab-separated-values, 10336 data points
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