An increase in new Sargassum (Phaeophyceae) blooms along the coast of the East China Sea and Yellow Sea

ABSTRACT

New macroalgal blooms caused by the genus Sargassum have been occurring along the coast of China. In particular, in 2017, Sargassum blooms covered up to 188 km² and drifted into the offshore region of Jiangsu Province, the traditional area for Pyropia aquaculture. This resulted in an enormous loss of production of Pyropia. This study was designed to identify the species composition, phylogenetic relationships, and possible origin of the free-floating Sargassum populations in the Yellow Sea and East China Sea. Results from morphological observations and molecular identification showed that Sargassum horneri was the only species comprising the blooms. Based on further satellite remote sensing analysis, the suspected origin of the blooms was the coastal area of Zhejiang Province, where S. horneri is widely distributed. This study increases our understanding of the importance of controlling the spread of macroalgae blooms.

KEYWORDS:

• Eutrophication
• Macroalgal blooms
• Origin
• Sargassum horneri
• Yellow Sea

ACKNOWLEDGEMENTS

The authors thank the crews working on the Songhang for collecting the floating Sargassum samples. We also express sincere thanks to Dr David Garbary, Editor of Phycologia, for his suggestions which improved our article. Thanks are also due to the reviewers for their valuable comments on the article.

Additional information

Funding

This study was sponsored by the National Key R&D Programme of China for Blue Granary (2018YFD0901500), Shanghai Sailing Programme (17YF1407900), National Natural Science Foundation of China (41576163), Jiangsu Marine Science and Technology Innovation Project (HY2017-4) and Ocean Public Welfare Scientific Research Project, China (201205010).