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Song W.,First Institute of Oceanography | Peng K.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | Xiao J.,First Institute of Oceanography | Li Y.,First Institute of Oceanography | And 6 more authors.
Estuarine, Coastal and Shelf Science | Year: 2014

Since 2007, large-scale green tides that primarily consisted of Ulva prolifera have consecutively invaded the coast of Qingdao (36°06'N, 120°25'E, PR China) in summer. The germination of green algae micro-propagules in the Subei Shoal played a significant role in the formation of these green tides. The change in sea temperature might be the key factor that affects the germination of the micro-propagules because the other environmental factors varied only slightly according to previous studies. This study was designed to investigate the effects of temperature on the germination of micro-propagules via laboratory experiments. The results showed the following: (1) five types of green algae micro-propagules, including U. prolifera, U. linza, U. compressa, Ulva sp. (Clade 6) and Blidingia sp., were detected in the seawater samples collected from the Subei Shoal; (2) at 5 °C, germinated micro-propagules were not detected in any of the samples; at 10 °C, the micro-propagules began to germinate, and the germination quantity markedly changed between 10 °C and 30 °C; (3) the germination numbers of U. prolifera, U. linza, Ulva sp. (Clade 6) and Blidingia sp. were maximized at 15 °C, 10 °C, 25 °C and 20 °C, respectively. This study indicated that the sea temperature played a significant role in the germination of green algae micro-propagules in water and could partly explain the community succession phenomenon of the attached green algae in the Subei Shoal. © 2014 Elsevier Ltd. All rights reserved.


Song W.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | Song W.,First Institute of Oceanography | Peng K.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | Xiao J.,First Institute of Oceanography | And 8 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

Since 2007, large-scale green tides that primarily consisted of Ulva prolifera have consecutively invaded the coast of Qingdao (36°06'N, 120°25'E, PR China) in summer. The germination of green algae micro-propagules in the Subei Shoal played a significant role in the formation of these green tides. The change in sea temperature might be the key factor that affects the germination of the micro-propagules because the other environmental factors varied only slightly according to previous studies. This study was designed to investigate the effects of temperature on the germination of micro-propagules via laboratory experiments. The results showed the following: (1) five types of green algae micro-propagules, including U. prolifera, U. linza, U. compressa, Ulva sp. (Clade 6) and Blidingia sp., were detected in the seawater samples collected from the Subei Shoal; (2) at 5 °C, germinated micro-propagules were not detected in any of the samples; at 10 °C, the micro-propagules began to germinate, and the germination quantity markedly changed between 10 °C and 30 °C; (3) the germination numbers of U. prolifera, U. linza, Ulva sp. (Clade 6) and Blidingia sp. were maximized at 15 °C, 10 °C, 25 °C and 20 °C, respectively. This study indicated that the sea temperature played a significant role in the germination of green algae micro-propagules in water and could partly explain the community succession phenomenon of the attached green algae in the Subei Shoal. © 2014 Elsevier Ltd.


Li Y.,First Institute of Oceanography | Song W.,First Institute of Oceanography | Song W.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | Xiao J.,First Institute of Oceanography | And 6 more authors.
Harmful Algae | Year: 2014

From 2008 to 2013, vast green tides mainly composed of Ulva prolifera consecutively invaded the coast of Qingdao (36°06'N, 120°25'E, PR China) in June and July. Previous studies have shown that the early green tides initially formed in the Porphyra yezoensis aquaculture area of the Subei Shoal, southern Yellow Sea. To date, multiple studies have demonstrated that green algae micro-propagules play an important role in the formation of green tides. In this study, we aimed to assess the temporal and spatial distribution of green algae micro-propagules in an extensive area of the Yellow Sea and to determine the species diversity of propagules during the development of the large-scale green tide. We found that the quantity of micro-propagules increased with the free-floating biomass from the initial generation to the development phase of the green tide in mid May. From late May to mid June, the micro-propagule density decreased sharply despite a continuous increase of the floating macroalgae biomass. In addition, our data indicate that the coastal area of the Subei Shoal has always been the distribution center of the micro-propagules, even prior to the large-scale green tide formation. Furthermore, diverse green algae species, including Ulva prolifera, Ulva linza, Ulva flexuosa, Ulva compressa, Ulva pertusa and Blidingia sp., were identified among the micro-propagules in the survey sea area. Finally, we determined that the distribution of U. prolifera micro-propagules is closely related to the floating algal mats and attached macroalgae on Porphyra aquaculture rafts. © 2014 Elsevier B.V.


Song W.,First Institute of Oceanography | Song W.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | Li Y.,First Institute of Oceanography | Li Y.,Hunan Provincial Key Laboratory of Phytohormones and Growth Development | And 8 more authors.
Estuarine, Coastal and Shelf Science | Year: 2015

The blooms of large-scale green tides in the Yellow Sea have become a focus of marine research in China. Micro-propagules, as the propagule source of green algae, played an important role in the formation of green tides. In this study, monthly surveys in the coastal area of the Subei Shoal were conducted from October 2010 to October 2011. The temporal and spatial distributions of green algae micro-propagules in the water column and sediment were investigated. Green algae micro-propagules were widely distributed in the waters and sediments throughout the year, and their distribution significantly corresponded to Porphyra aquaculture activities. The abundance of the micro-propagules decreased gradually from inshore to offshore. The average number of micro-propagules reached a maximum in late April and was low during the winter and summer. The source of the micro-propagules was the green algae attached to the Porphyra aquaculture rafts. The green algae micro-propagules might serve as the seed stock of the raft-attached green algae and provide the initial conditions for the formation of green tides. © 2014 Elsevier Ltd.

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