Photosynthetic activity buffers ocean acidification in seagrass meadows

• Main Authors: Hendriks, Iris, Olsen, Ylva, Ramajo, L, Basso, L, Steckbauer, Alexandra, Moore, T S, Howard, J, Duarte, Carlos Manuel
• Format: Dataset
• Language: English
• Published: PANGAEA 2014
• Subjects: Alkalinity; total; Aragonite saturation state; Benthos; Bicarbonate ion; Biomass; Biomass/Abundance/Elemental composition; Calcite saturation state; Calcium carbonate; inorganic; Calculated using seacarb after Nisumaa et al. (2010); Carbon; dissolved; Carbonate ion; Carbonate system computation flag; Carbon dioxide; Coast and continental shelf; Field observation; Flow velocity; water; standard error; Fugacity of carbon dioxide (water) at sea surface temperature (wet air); Growth/Morphology; Illuminance; standard deviation; Leaf area index; Macroalgae; Mediterranean Sea; Mediterranean Sea Acidification in a Changing Climate; MedSeA; OA-ICC; Ocean Acidification International Coordination Centre; Oxygen; Partial pressure of carbon dioxide (water) at sea surface temperature (wet air); pH; Plantae; Posidonia oceanica; Potentiometric; Pyrheliometer; Eppley; NIP; SN 16523E6; WRMC No. 31296; Salinity; Ocean acidification
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.834083; https://doi.org/10.1594/PANGAEA.834083

Macrophytes growing in shallow coastal zones characterised by intense metabolic activity have the capacity to modify pH within their canopy and beyond. We observed diel pH changes in shallow (5-12 m) seagrass (Posidonia oceanica) meadows spanning 0.06 pH units in September to 0.24 units in June. The carbonate system (pH, DIC, and aragonite saturation state (omega Ar)) and O2 within the meadows displayed strong diel variability driven by primary productivity, and changes in chemistry were related to structural parameters of the meadow, in particular, the leaf surface area available for photosynthesis (LAI). LAI was positively correlated to mean, max and range pHNBS and max and range omega Ar. In June, vertical mixing (as Turbulent Kinetic Energy) influenced max and min omega Ar, while in September there was no effect of hydrodynamics on the carbonate system within the canopy. Max and range omega Ar within the meadow showed a positive trend with the calcium carbonate load of the leaves, pointing to a possible link between structural parameters, omega Ar and carbonate deposition.