Who made the world's largest green tide in China?—an integrated study on the initiation and early development of the green tide in Yellow Sea

Abstract

To discover the original source and clarify development of the world's largest transregional green tides in the Yellow Sea, an integrated investigation covering the Subei Shoal coastal waters and the adjacent regions was carried out during March to June of 2012. The results showed that macroalgal wastes from the connecting ropes of Porphyra aquaculture rafts contributed significantly to the original biomass of free-floating green algae. Approximately 6500 t of Ulva prolifera were released into the coastal waters from mid-April to late-May when farmers were cleaning aquaculture facilities. Among the total biomass disposed, about 62.3% floated up to the sea surface, which turned into the original floating patches. The floating U. prolifera, with a high growth rate of 26.3% per day, dominated in the floating algal patches rapidly, moved northward under the hydrodynamic action, and formed a massive free-floating green tide near the south of Shandong peninsula in early June. The optimal sea temperature and sufficient nutrients in the Yellow Sea facilitated the formation of the green tide. No other source contributing substantially to the initial floating biomass was detected in the survey except those from the connecting ropes of rafts. Based on our field data, we concluded that the green tide in Yellow Sea is a transregional disaster stimulated directly by the unhygienic husbandry and maintenance practices of coastal aquaculture.

Mapping macroalgal blooms in the Yellow Sea and East China Sea using HJ-1 and Landsat data: Application of a virtual baseline reflectance height technique

“…suggested that they were from the "nori" (seaweed Pyropia yezoensis) farming facilities in the JS (Xing, Tosi, Braga, Gao, & Gao, 2015a): at the end of April (after the nori harvesting season) when the facilities (bamboo poles, ropes) were removed and recycled, the green macroalgae (Ulva spp.) growing on the facilities were also removed and deserted in the sea water, serving as the seed source of MABs (China Ocean News, CON, 2013;Wang, Xiao, Fan, Li, Liu, & Liu, 2015). An alternative explanation is that the seeds were released from the animal (crabs and prawns) aquaculture ponds in April (Pang, Liu, Shan, Xu, Zhang, Gao, Chopin, & Sun, 2010).…”

Long-term trend of Ulva prolifera blooms in the western Yellow Sea

“…Since then, macroalgae blooms are observed in May-August period every year in this region. Numerous studies have documented their growth cycles, seasonality, transport patterns, and their linkage with local aquaculture, eutrophication, and ocean circulations (Hu et al, 2010;Liu et al, 2009Liu et al, , 2013Wang et al, 2015). However, to date, although a number of studies used remote sensing to estimate their spatial distributions and temporal changes, nearly all focused on how to effectively detect the presence of the macroalgae (Cui et al, 2012;Hu, 2009;Hu et al, 2010;Keesing et al, 2011;Lee et al, 2011;Garcia et al, 2013;Bao et al, 2015;Xing and Hu, 2016).…”

Tracking the Movement and Distribution of Green Tides on the Yellow Sea in 2015 Based on GOCI and Landsat Images

“…The detection of the algal mass in the 500 m resolution GOCI images just two days after initial detection in the 30 m Landsat images is indicative of the high growth rate of floating green algae. Wang et al (2015) stated that floating U.…”

“…Green tides sink over time (Lü and Qiao, 2008;Wang et al, 2015) and off the coast of China, most green tides sink in the waters off the Korean Peninsula after passage through the Yellow Sea.…”

“…Prior to this study, the characteristic reflectance properties of Ulva prolifera, the main type of floating green algae in the region were known (Liu et al, 2010;Luo et al, 2012;Huo et al, 2013;Zhao et al, 2013;Wang et al, 2015). Data from the 500 m spatial resolution Communication, Ocean, and…”