Green tidal algal Enteromorpha species complete their life cycles by the isomorphic alternation of generations. The provenance of green tide caused by them in the western Yellow Sea has been disputed. The cell reproduction derived from adult thallus was observed on E. clathrata collected from Shantou City, Guangdong Province in this study. Subsequently, it further found that E. proliferia collected from Qingdao City, Shandong Province and Qinhuangdao City, Hebei Province, produced reproductive cells by somatic cells of its early infantile thallus or branch. The latter is functionally similar to that the seedlings of red alga Porphyra yezoensis produce the monospores, and could exquisitely explain the ephemeral or opportunistic trait and environmental adaptation ability of Enteromorpha species. Changes in growth conditions may induce the two types of cell reproduction. They contribute to the bloom, and can effectively reveal the seasonally occurring large-scale and on-year and off-year phenomenon. The latter may have played a decisive role in its formation. This paper analyses the legal status of the species name, the type of generation during bloom, ephemeral traits, the role of microscopic propagule, the area of origin, on-year and off-year phenomenon, early warning and prevention and control of the species, and so on. On this basis, further study on the influence of environmental factors on cell reproduction of early infantile thalli or branches will achieve a positive effect for early warning and prevention and control of the green tidal algal bloom.
