Seawater carbonate chemistry and abiotic and biotic interactions in the diffusive boundary layer of kelp blades ...

• Main Authors: Noisette, Fanny, Hurd, Catriona L
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2018
• Subjects: Benthos; Chromista; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Laboratory experiment; Macroalgae; Ochrophyta; Other; Other metabolic rates; Primary production/Photosynthesis; Single species; South Pacific; Temperate; Ocean Acidification International Coordination Centre OA-ICC; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.885874; https://doi.pangaea.de/10.1594/PANGAEA.885874

Seaweeds are able to modify the chemical environment at their surface, in a micro‐zone called the diffusive boundary layer (DBL), via their metabolic processes controlled by light intensity. Depending on the thickness of the DBL, sessile invertebrates such as calcifying bryozoans or tube‐forming polychaetes living on the surface of the blades can be affected by the chemical variations occurring in this microlayer. Especially in the context of ocean acidification (OA), these microhabitats might be considered as a refuge from lower pH, because during the day photosynthesis temporarily raises the pH to values higher than in the mainstream seawater.We assessed the thickness and the characteristics of the DBL at two pH levels (today's average surface ocean pH 8.1 and a reduced pH predicted for the end of the century, pH 7.7) and seawater flows (slow, 0.5 and fast, >8 cm/s) on Ecklonia radiata (kelp) blades. Oxygen and pH profiles from the blade surface to the mainstream seawater were measured with O2 and pH ...