The drifting and spreading mechanism of floating Ulva mass in the waterways of Subei shoal, the Yellow Sea of China – Application for abating the world's largest green tides. (May 2023)

• Record Type: Journal Article
• Authors: Wang, Zongling; Xiao, Jie; Yuan, Chao; Miao, Xiaoxiang; Fan, Shiliang; Fu, Mingzhu; Xia, Tao; Zhang, Xuelei
• Is Part Of: Marine pollution bulletin. Volume 190(2023)
• Publication Date: 2023-05
• Subjects: Green tide -- Ulva -- Floating biomass -- Subei Shoal -- Green tide containment; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2023.114789
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: The large-scale green tides have been prevailing in the Yellow Sea over a decade. Prevention and control techniques in the source region (Subei Shoal) are urgently needed to minimize its adverse ecological and social impacts. Drifting and spreading mechanism of Ulva mass was investigated in the Subei Shoal in order to develop the early containment measures. The multidisciplinary surveys suggested twelve major waterways transporting the initial Ulva mass which was closely related to the basin topology and water circulation in the shoal. The epiphytic algal mass from the northern and eastern raft regions contributed 82.7 % of the initial floating biomass, and moved out in 4–6 days with an average drifting velocity of 0.28 m s −1 . Accordingly, two series of algae-blocking lines were proposed to remove floating mass from the shoal. And the primary field trial in 2018 confirmed the feasibility of this strategy to abate the green tides. Highlights: The floating Ulva was transported out of Subei Shoal through 12 major waterways, especially the northern and eastern five. The movement of initial floating Ulva mass was influenced by the basin topology and accumulated along the sand grooves. The biomass flux in each waterway was linearly correlated with the source epiphytic Ulva algae from the aquaculture rafts. Two series of blocking lines were proposed to remove the initial floating mass and mitigate the green tides.