Phenological study of Sargassum thunbergii (Fucales, Phaeophyta) in Lidao Bay, Rongcheng, China

Abstract

We conducted a phenological evaluation of Sargassum thunbergii , a common algal species, along the coast of Lidao Bay, Rongcheng, China. The local S . thunbergii population entered a maturation period from early June to mid-August, when seawater temperature was 14.4 to 25.1°C. Our results suggest an increase in temperature and day length during this period initiated thalli maturation. Inhabitants of the low tidal zone had higher thalli length and biomass compared with those from the mid-and high tidal zones. We observed a switch in the length frequency distribution and contribution of length classes to biomass between the small (<20 cm) and long (20-79.9 cm) length classes at the time of thallus maturity. This suggests there is a trade-off between sexual reproduction and vegetative regeneration.

Effects of Temperature, Photon Irradiance and Photoperiods on the Early Growth of Sargassum thunbergii

“…It is also used as feed for invertebrates in China, particularly by sea cucumbers, because of its high nutritional value. Studies of Sargassum thunbergii have been conducted mainly in China and Japan, and include the reproductive biology of Sargassum thunbergii (Liang et al, 2014), osmosis, and desiccation stress, which affects the heat tolerance of germinated Sargassum thunbergii thalli (Chu et al, 2012), the early developmental stages of germinated young thalli under indoor culture (Zhao et al, 2008), the phylogenetics of Chinese Sargassum thunbergii (Liu et al, 2016), and large-scale culture (Liu et al, 2021). In Japan, studies have concentrated on the ecology and cultivation of Sargassum thunbergii (Umezaki, 1974).…”