An accurate estimation of gross primary production in macroalgal beds is necessary to understand the carbon cycle in shallow coastal waters. In this study, the primary production of two Sargassum species (Myagropsis myagroides and Sargassum macrocarpum) commonly found along the coast of Japan was measured using the 13C-labelling method, focusing on morphologically distinct sections (blade, stipe, and holdfast including the perennial parts), as well as the apical tip. The blades and apical tips of M. myagroides showed higher production rates, consistent with its adaptation to high-light conditions. In contrast, S. macrocarpum exhibited stable photosynthetic performance under low-light conditions. Compared to conventional yield measurements (calculated only from the blade and the apical tip), the production calculated using the weighted average of each section’s production and its weight composition was approximately 60%. This helps improve the conventional measurement method, which is likely prone to overestimation (or underestimation).
Miyata T, et al., Phycological Research, 2025. DOI: https://doi.org/10.1111/pre.70006.
