Seawater carbonate chemistry and net community calcification (NCC) and net community production (NCP) rates of individual taxa and combined reef communities

• Main Authors: Silbiger, N J, Nelson, Craig E, Remple, Kristina, Sevilla, Jessica K, Quinlan, Zachary A, Putnam, H M, Fox, M D, Donahue, M J
• Format: Dataset
• Language: English
• Published: PANGAEA 2018
• Subjects: Alkalinity; total; Animalia; Aquarium number; Aragonite saturation state; Ash free dry mass; Benthos; Bicarbonate ion; Bottles or small containers/Aquaria (<20 L); Calcification/Dissolution; Calcite saturation state; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Cnidaria; Coast and continental shelf; Coconut_Island; DATE/TIME; Dry mass; Entire community; EXP; Experiment; Flow rate; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Gracillaria salicornia; Gross primary production of oxygen; Identification; Laboratory experiment; Light mode; Macroalgae; Macro-nutrients; Montipora capitata; Net calcification rate of calcium carbonate; Net primary production of oxygen; Nitrate and Nitrite; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Phosphate; Plantae; Porites compressa; Potentiometric; Potentiometric titration; Pacific; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.924534; https://doi.org/10.1594/PANGAEA.924534

There is a long history of examining the impacts of nutrient pollution and pH on coral reefs. However, little is known about how these two stressors interact and influence coral reef ecosystem functioning. Using a six-week nutrient addition experiment, we measured the impact of elevated nitrate (NO−3) and phosphate (PO3−4) on net community calcification (NCC) and net community production (NCP) rates of individual taxa and combined reef communities. Our study had four major outcomes: (i) NCC rates declined in response to nutrient addition in all substrate types, (ii) the mixed community switched from net calcification to net dissolution under medium and high nutrient conditions, (iii) nutrients augmented pH variability through modified photosynthesis and respiration rates, and (iv) nutrients disrupted the relationship between NCC and aragonite saturation state documented in ambient conditions. These results indicate that the negative effect of NO−3 and PO3−4 addition on reef calcification is likely both a direct physiological response to nutrients and also an indirect response to a shifting pH environment from altered NCP rates. Here, we show that nutrient pollution could make reefs more vulnerable to global changes associated with ocean acidification and accelerate the predicted shift from net accretion to net erosion.