Mechanism Of Floating And Sinking For Ulva Prolifera

Green algal blooms have occurred in the Yellow Sea of China for eight consecutive years since 2007. Floating green tides algae appears in April or May every year, its biomass also shows explosive growth during the process of drifting to the north, until dying out in August at shandong coastal. The green tides blooms in the Yellow Sea were mainly caused by the rapid growth of floating Ulva and large-scale drifting with the waves, while the featur of floating is an important factor for macroalgal blooms. There were some reports about floating Ulva having air-sac structure,but no specific mechanism studies about the Ulva form into the air-sac in domestic and foreign reports, and no detailed study of specific morphological characteristics. In this study, floating and sinking mechanism of the Yellow Sea green tides dominant species were studied, starting with the morphological study of the cause of dominant species seagrass green tide airbag structure formation process was observed; the other, from the physical aspect of the study of photosynthesis float Ulva a long-term floating dark adaptation mechanisms and strategies; and third, to Ulva algae physiological characteristics and mechanism of the sinking were discussed, laid the theoretical foundation for further elucidate the mechanism Hu moss green tide outbreaks.1. Formation of pipes and air-sac of UlvaThe main observations and morphological aspects of the algae research pipeline and an airbag green tide algae Ulva seedlings dominant species formed during the development process, including Ulva spores / gametes diffuse, seedling germination, frond development and pipeline structure formation, branch formation and balloon formation process. U.prolifera after cell maturation can diffuse a lot of propagules, each spore / gamete can develop into an independent mature seagrass. Seedlings during germination, propagation body gradually develops into a monolayer tubular structure and differentiate fronds and rhizoid, the tubular algae can form numerous branches, while the absorption of nutrients can also live in seawater bubbles suspended in order to achieve algae floating effect. After lumen mature fronds bent to form a "node", filled with gas in a closed section formed algae balloon, the balloon can float so seagrass in the sea a long time. This study reveals the formation of algae pipes and balloon floating mechanism is U.prolifera internal factor, it laid the theoretical foundation for the further clarification of U.prolifera float mechanism and green tide outbreaks mechanism.2. Mechanism of long distance floating for Ulva in the Yellow SeaOn the basis of the process of the formation of the balloon research on the study of the process of floating green tide algae underwater seagrass way to escape hanging high illumination intensity Stress and Physiological ecology. From 2012 to 2014 for 3 consecutive years in the Yellow Sea green tide floats drift tracking and monitoring process, monitoring results show that the floating algae afloat and can be divided into two parts underwater suspension, of floating algae due to the high intensity stress and most gradually White died while flying underwater algae can avoid high light intensity Stresses survive. July 2014 in Qingdao green tide algae floating in the waters acquisition, branching tubular balloon and fly the chlorophyll fluorescence parameters were observed buoyancy measurements and microscopic cell structures. U.prolifera mostly white balloon floating green, Fv/Fm values averaged about 0.29, chlorophyll content of about 0.32mg/g, cytoplasm majority shifted or atrophy discoloration, and another part of the balloon bladder cells to form germ cells or diffuse out of the breeding Hanging branches mostly green and Fv/Fm values are relatively high, averaging about 0.6, relatively high chlorophyll content was 0.87mg/g, the cell contents filling, only a small fraction of cells began to shrink; body. After hanging branches culture; the airbag main branch and hanging branches at 25 ℃, under 80μmol/m2 s environmental observation again after a week of culture, the cells balloon bough basic reproductive cells are formed or diffuse into the air sac cells It remains healthy growth, shrinking cytoplasm ratio decreases.3. Mechanism of Sinking for UlvaEach year in early August green tide began to enter the decline phase, the area decreases. May to July 2014 on the floating U.prolifera were tracking and monitoring, in July set up six stations sites in Qingdao U.prolifera acquisition settlement. The collected green tide algae were observed microscopic cell structure determination and chlorophyll fluorescence parameters. Measured sedimentation green tide algae chlorophyll fluorescence parameters average of 0.68, the total chlorophyll content of 1.44mg/g, compared with floating seagrass higher in a healthy state, cells were vegetative cell state, only a small amount of cytoplasm shrinking discoloration. Cultured under suitable conditions still capable of rapid vegetative propagation, no bag produce germ cells, photosynthesis and chlorophyll fluorescence parameters decreased slightly, Fv/Fm values average of 0.65, the total chlorophyll content was reduced to 1.27mg/g. By dark treatment simulation study of morphological and physiological state U.prolifera change state under the seabed matte, seagrass stop growing and even showed rotting state, significantly decreased the photosynthetic physiological state, Fv/Fm values average of 0.09, the total chlorophyll content of 0.14 mg/g, cytoplasmic atrophy, cell wall degrading release protoplasts.