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Distribution of green algae micro-propagules and their function in the formation of the green tides in the coast of Qinhuangdao, the Bohai Sea, China
Han Hongbin, Song Wei, Wang Zongling, Ding Dewen, Yuan Chao, Zhang Xuelei, Li Yan
2019, 38(8): 72-77. doi: 10.1007/s13131-018-1278-1
Keywords: green tides, micro-propagules, macroalgae, Qinhuangdao, Bohai Sea
Since 2015, a novel green tide has been recurring in the coastal areas of Qinhuangdao at the western coast of the Bohai Sea in China, threatening the environment and ecosystem of the Beidaihe seaside holiday resort along the coast. Micro-propagules of the green algae including gametes, spores, micro-germlings and micro-vegetative fragments play an important role in the formation of green tides. They serve as a “seed source” of green macroalgae, and their distributions could reflect and influence the “algae source” of green tides. In this study, monthly surveys in the inshore and offshore areas of the Qinhuangdao coast were conducted from April to September 2016 and in January 2017 to investigate the tempo-spatial distribution patterns and the biomass variations of the green algae micro-propagules. The obtained results show that micro-propagules were mainly distributed in the inshore areas with a significantly decreasing abundance towards offshore areas. Their biomass was highest in July and August, and lowest in winter. The areas that were affected by the green tides showed a remarkably higher abundance of micro-propagules compared to other areas. These micro-propagules could serve as the “seed” source of green tides. Their distribution patterns indicate that the green tide in the coastal areas of Qinhuangdao originated locally.
The current situations of green macroalgae and micro-propagules in Pyropia aquaculture of the Subei Shoal in spring of 2013
LIU Xiangqing, WANG Zongling, FAN Shiliang, XIAO Jie, LI Yan, ZHANG Xuelei, LI Ruixiang, WANG Xiaona
2016, 35(6): 94-100. doi: 10.1007/s13131-016-0879-9
Keywords: distribution, Subei Shoal, green algal micro-propagules, green macroalgae
To discover the distribution of green algal micro-propagules in the Subei Shoal and clarify the growth of green macroalgae attached on Pyropia aquaculture rafts, an integrated investigation in Pyropia aquaculture area and one cruise in the coastal area of the Subei Shoal were carried out from March to May in 2013. The results showed that green algal micro-propagules were discovered in seawater and sediment during March to May. The average quantity of micro-propagules was 267 ind./L in surface seawater and 43 ind./g in sediment. The biomass of attached green macroalgae increased in Pyropia aquaculture from March to May. Three species, including Ulva prolifera, Ulva linza and Blidingia sp. were found in Pyropia aquaculture rafts. The dominant specie was Blidingia sp. and the second was U. prolifera in spring. This study indicated that the micro-propagules and macroalgae were existed in the coastal area of the Subei Shoal at the early stage of green tide. This was the key point to the governance of green tide in China.
Source of propagules of the fouling green macroalgae in the Subei Shoal, China
SONG Wei, JIANG Meijie, WANG Zongling, WANG Hongping, ZHANG Xuelei, FU Mingzhu
2018, 37(4): 102-108. doi: 10.1007/s13131-018-1169-5
Keywords: green tides, source of propagules, Ulva prolifera, anti-fouling
Since 2007, large-scale green tides dominated by Ulva prolifera consecutively bloomed in the Yellow Sea and caused great economic losses. The fouling U. prolifera on the Pyropia yezoensis aquaculture rafts in the Subei Shoal was regarded as the major source of the floating biomass. However, it was still unclear about the seed source of fouling green macroalgae attached on the rafts. In this study, the field surveys and the indoor experiments were conducted to reveal the source of propagules of the fouling green macroalgae on the rafts and to study the anti-fouling material for P. yezoensis aquaculture rafts which could possibly be a feasible strategy to control the green tides in the Yellow Sea. The results showed that (1) micro-propagules of several green macroalgal species, including U. prolifera, U. linza, U. compressa, U. flexuosa, and Blidingia sp. coexisted in the waters and sediments in the Subei Shoal and their proportion remarkably changed over time; (2) the bamboo poles with peeling treatment could significantly reduce the amount of U. prolifera micro-propagules attached. This study confirmed that the micro-propagules distributed in the Subei Shoal area were the precursors of the green tides, and provided a feasible method to control the Yellow Sea large-scale green tides at the beginning.
Micro-phytoplankton distribution and biomass in and around a channel-based fish farm: implications for sustainable aquaculture
SADALLY S. B, NAZURALLY N, TALEB-HOSSENKHAN N, BHAGOOLI R
2014, 33(12): 180-191. doi: 10.1007/s13131-014-0577-4
Keywords: chlorophyll a, micro-phytoplankton, physico-chemical parameters, sustainable aquaculture
Micro-phytoplankton density, genera composition, chlorophyll a concentration, and physico-chemical parameters were investigated at five stations (S1—near the coast; S2 and S4—at the edges of the aquaculture set-up; S3—in the center of the set-up; and S5—nearby patch of corals) in and around a coastal channelbased fish farm. The highest total micro-phytoplankton density (TPD), including diatoms, dinoflagellates and cyanobacteria, was recorded at S3 ((6.28±2.00)×106 cells/L) followed by S4 ((5.87±2.81)×105 cells/L), S1 ((4.92×105±8.70×104) cells/L), S5 ((3.54×105±5.33×104) cells/L) and S2 ((2.60±1.14)×105 cells/L). Chlorophyll a and nutrient concentrations were highest at S3 and were positively correlated with TPD. Among the 35 genera documented in this study, Chaetoceros spp. was the dominant diatom while Peridinium spp. was the most dominant dinoflagellate. Very low densities of toxic bloom-forming dinoflagellates were encountered during this study. These results suggest that occurrence of non-bloom densities of micro-phytoplankton, possibly due to the natural flushing of the existing lagoonal channel at the aquaculture site, yielded in little environmental impact and can represent an appropriate sustainable approach for future aquaculture development.
Research on extracting method of micro-scale remote sensing information combination and application in coastal zone
YANG Xiaomei, ZHOU Chenghu, GONG Jianming, GAO Zhenyu
2009(5): 30-38.
Keywords: Object-oriented, Image Segmentation, Coastal Zone, Information Extraction
Due to the need of rapid and sustainable development in China's coastal zones,the high-resolution information theory using data mining technology becomes an urgent research focus.However,the traditional pixel-based image analysis methods cannot meet the needs of this development trend.The paper attempts to present an information extraction approach in terms of image segmentation based on an object-oriented algorithm for high-resolution remote sensing images.An aim of the author' research is to establish an identification system of "pixel-primitive-object".Through extraction and combination of micro-scale coastal zone features,some objects are classified or recognized,e.g.,tidal flat,water line,sea wall,and mariculture pond.Firstly,the authors extract various internal features of relatively homogeneous primitive objects using an image segmentation algorithm based on both spectral and shape information.Secondly,the features of those primitives are analyzed to ascertain an optimal object by adopting certain feature rules.The results from this research indicate that our model is practical to realize and the extraction accuracy of the coastal information is significantly improved as compared with the traditional approaches.Therefore,this study provides a potential way to serve the author' highly dynamic coastal zones for monitoring,management,development and utilization.
Layer-block tectonics of Cenozoic basements and formation of intra-plate basins in Nansha micro-plate, southern South China Sea
LIU Hailing, XIE Guofa, LIN Qiujin, ZHENG Hongbo, LIU Yingchun
2009(3): 26-39.
Keywords: layer-block tectonics, forming mechanism of intra-plate basin, Nansha micro-plate, South China Sea, oil and gas, gas hydrate
Layer-block tectonics (LBT) concept, with the core of pluralistic geodynamic outlook and multilayer-sliding tectonic outlook, is one of new keys to study 3-dimensional solid and its 4-dimensional evolution history of global tectonic system controlled by global geodynamics system. The LBT concept is applied to study the lithospheric tectonics of the southern South China Sea (SCS). Based on the analysis of about 30 000 km of geophysical and geological data, some layer-blocks in the Nansha micro-plate can be divided as Nansha ultra-crustal layer-block, Zengmu crustal layer-block, Nanwei (Rifleman bank)-Andu (Ardasier bank) and Liyue (Reed bank)-North Palawan crustal layer-blocks, Andu-Bisheng and Liyue-Banyue basemental layer-blocks. The basic characteristics of the basemental layer-blocks have been dicussed, and three intra-plate basin groups are identified. The intra-plate basins within Nansha micro-plate can be divided into three basin groups of Nanwei-Andu, Feixin-Nanhua, and Liyue-North Palawan based on the different geodynamics. In the light of pluralistic geodynamic concept, the upheaving force induced by the mid-crust plastic layer is proposed as the main dynamical force which causes the formation of the intra-plate basins within the Nansha micro-plate. Finally, models of a face-to-face dip-slip-detachment of basemental layerblock and a unilateral dip-slip-detachment of basemental layer-block are put forward for the forming mechanisms of the Nanwei-Andu and Liyue-North Palawan intra-plate basin groups, respectively.
Transport patterns of micro nutrient elements from the continental shelf of the East China Sea to the Kuroshio area
Lu Saiying, Yao Qiao'er, Chen Zhen
1992(2): 219-230.
On the basis of the in situ data of DO2, pH, SiO2, PO4-P, NO3-N and NO2-N collected in the north of the East China Sea during 1987-1988, the following points are mainly expounded.
1.The inorgonic nutrients are obviously affected by continent runoff in the north of the East China Sea. Their distributions are characteristic of its distribution of terrigenous materials.
2.There are three transport paths of nutrients from the shelf to the Kuroshio area. The first is mixing-diffusing-advection and upwelling process, the process of biology and biochemistry belongs to the second, and the sinking process is the last one.
3.The swing of the Kuroshio axis affectes both the range of the migration of substances through mixing-diffusing-advection process and the upwelling degree of the subsurface Kuroshio water to the shelf.
4.Most part of the substances sink as macroparticles to the deep layer before reaching the Kuroshio area.
A MICRO-FLUORESCENT METHOD FOR THE DE TERMINATION OF FREE AMINO ACIDS IN SEA-WATER AND THE DISTRIBUTION OF TOTAL FREE AMINO ACIDS
MING XIUREN, HU QINXIAN, ZHU BIYING, LIU ZILIN, YANG WANLUN
1985(1): 121-130.
O-phthaldialdehyde is used for the determination of free amino acid in seawater by measuring the fluorescence produced by its reaction with the a-amino group of amino acids. This method is so sensitive that as little as 1-10 nM of amino acids and less than 1 ml of seawater may be sufficient for one test.
This method is simple, rapid and accurate and a-amino acids contained in seawater can directly be determined without concentration and extraction. It is free from the interference of large content of inorganic salts and other nitrogenous compounds in seawater.
A hundred and fifty-two samples collected at 24 stations in offshore of Zhejiang have been analyzed. The results obtained show that the range of concentration of the total free amino acid is 0.37-4.70 μM. The values are high near shore and low offshore.
An experimental study on microscopic characteristics of gas-bearing sediments under different gas reservoir pressures
Zhenqi Guo, Tao Liu, Lei Guo, Xiuting Su, Yan Zhang, Sanpeng Li
2021, 40(10): 144-151. doi: 10.1007/s13131-021-1834-y  Published:2021-10-30
Keywords: micro characteristics, CT scanning, gas content, number and volume of bubbles, gas reservoir pressure, seabed sediments
Gas-bearing sediments are widely distributed in five continents all over the world. Most of the gases exist in the soil skeleton in the form of discrete large bubbles. The existence of gas-phase may increase or decrease the strength of the soil skeleton. So far, bubbles’ structural morphology and evolution characteristics in soil skeleton lack research, and the influence of different gas reservoir pressures on bubbles are still unclear. The micro characteristics of bubbles in the same sediment sample were studied using an industrial CT scanning test system to solve these problems. Using the image processing software, the micro variation characteristics of gas-bearing sediments in gas reservoir pressure change are obtained. The results show that the number and volume of bubbles in different equivalent radius ranges will change regularly under different gas reservoir pressure. With the increase of gas reservoir pressure, the number and volume of tiny bubbles decrease. In contrast, the number and volume of large bubbles increase, and the gas content in different positions increases and occupies a dominant position, driving the reduction of pore water and soil skeleton movement.
Oscillopolarographic determination of microsillicon in seawater
Chen Liyi
1990(4): 555-560.
A new oscillopolarographic method for the determination of Si (Ⅳ) is described in this paper. In the system HCl-Sb(Ⅲ)-Mo(Ⅵ)-NaCl-ethyl alcohol, Si (Ⅳ) with Sb (Ⅲ) and Mo (Ⅵ) form ternary heteropoly acid. The anion of ternary heteropoly is adsorbed on the dropping mercury electrobe and under proper electric potentials reduced quickly into heteropoly blue. The process of electrochemical reaction will produce a sensitive polarographic wave with peak potential at -0.30(Vs. SCE). The lower limit of determination is 8×10-8 mol/dm3. This method is sensitive, accurate and extremely rapid for the determination of micro-silicon in seawater.
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