Seawater carbonate chemistry and net community production and net ecosystem calcification in tide pools

• Main Authors: Bracken, Matthew E S, Silbiger, N J, Bernatchez, Genevieve, Sorte, Cascade J B
• Format: Dataset
• Language: English
• Published: PANGAEA 2018
• Subjects: Alkalinity; total; Ammonium; Aragonite saturation state; Area; Benthos; Bicarbonate ion; Calcification/Dissolution; Calcite saturation state; Calculated using seacarb after Nisumaa et al. (2010); Carbon; inorganic; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; air-sea; flux; Coast and continental shelf; Community composition and diversity; Containers and aquaria (20-1000 L or < 1 m**2); Coverage; Day of experiment; Difference; Entire community; EXP; Experiment; Field experiment; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Horseshoe_Cove_OA; Identification; Irradiance; Net calcification rate of calcium carbonate; Net community production; dissolved inorganic carbon; Nitrate and Nitrite; North Pacific; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Phosphate; Primary production/Photosynthesis; Rocky-shore community; Salinity; Surface area; Temperate; Pacific; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.924379; https://doi.org/10.1594/PANGAEA.924379

Predicting the impacts of ocean acidification in coastal habitats is complicated by bio-physical feedbacks between organisms and carbonate chemistry. Daily changes in pH and other carbonate parameters in coastal ecosystems, associated with processes such as photosynthesis and respiration, often greatly exceed global mean predicted changes over the next century. We assessed the strength of these feedbacks under projected elevated CO2 levels by conducting a field experiment in 10 macrophyte-dominated tide pools on the coast of California, USA. We evaluated changes in carbonate parameters over time and found that under ambient conditions, daytime changes in pH, pCO2, net ecosystem calcification (NEC), and O2 concentrations were strongly related to rates of net community production (NCP). CO2 was added to pools during daytime low tides, which should have reduced pH and enhanced pCO2. However, photosynthesis rapidly reduced pCO2 and increased pH, so effects of CO2 addition were not apparent unless we accounted for seaweed and surfgrass abundances. In the absence of macrophytes, CO2 addition caused pH to decline by ∼0.6 units and pCO2 to increase by ∼487 µatm over 6 hr during the daytime low tide. As macrophyte abundances increased, the impacts of CO2 addition declined because more CO2 was absorbed due to photosynthesis. Effects of CO2addition were, therefore, modified by feedbacks between NCP, pH, pCO2, and NEC. Our results underscore the potential importance of coastal macrophytes in ameliorating impacts of ocean acidification.