Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and t...Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and their roles in algal blooms remain unknown. In this study, based on previous research findings that fluid motion may stimulate the colony formation in green algae, cul^are experiments were conducted under axenic conditions in a circular water chamber where the flow rate, temperature, light, and nutrients were controlled. The number of cells of Microcystis aeruginosa, the number of cells per colony, and the colonial characteristics in various growth phases were observed and measured. The results indicated that the colony formation in Microcystis aeruginosa, which was not observed under stagnant conditions, was evident when there was fluid motion, with the number of cells per largest colony reaching 120 and the proportion of the number of cells in colonial form to the total number of cells and the mean number of cells per colony reaching their peak values at a flow rate of 35 crn/s. Based on the analysis of colony formation process, fluid motion stimulates the colony formation in Microcystis aeruginosa in the lag growth phase, while flushes and disaggregates the colonies in the exponential growth phase. The stimulation effect in the lag growth phase may be attributable to the involvement of fluid motion in a series of physiological processes, including the uptake of trace elements and the synthesis and secretion of polysaccharides. In addition, the experimental groups exhibiting typical colonial characteristics in the lag growth phase were found to have higher cell biomass in the later phase.展开更多
CCS技术是Carbon Capture and Storage的缩写,是一项将二氧化碳(CO_(2))捕获和封存的技术,是稳定大气温室气体浓度减缓行动组合中的一种选择方案。中国海油CCS示范项目利用一口超浅层大位移井,将油田开发过程中高含量二氧化碳原位处置...CCS技术是Carbon Capture and Storage的缩写,是一项将二氧化碳(CO_(2))捕获和封存的技术,是稳定大气温室气体浓度减缓行动组合中的一种选择方案。中国海油CCS示范项目利用一口超浅层大位移井,将油田开发过程中高含量二氧化碳原位处置回注至类似“穹顶”地质构造,以达到二氧化碳封存的目的。目标井深度3709 m,垂深仅894.31 m,水平段延伸长度3212.96 m,水垂比达3.59,是一口超浅层大位移水平井。固井专业面临低温泥饼不易冲洗、长尾管段回接居中度差和插入难、水泥环易腐蚀和难修复、浅层疏松地层易漏等技术难题。中海油服发挥自身技术优势,对技术难题一一化解,保障了示范项目成功实施。2023年6月,伴随着回注系统将二氧化碳以每小时9吨的速度回注至地层,中国海油CCS示范项目正式投产,作为中国海油自主设计的首口回注井,标志着我国初步形成了海上二氧化碳注入、封存和监测的全套钻完井技术和装备体系,填补了我国海上二氧化碳封存技术的空白。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 50979028)the Special Fund of Research for Public Welfare Industry of the Ministry of Water Resources of China (Grant No. 200801065)
文摘Microcystis aeruginosa, generally occurring in large colonies under natural conditions, mainly exists as single cells in laboratory cultures. The mechanisms involved in colony formation in Microcystis aeruginosa and their roles in algal blooms remain unknown. In this study, based on previous research findings that fluid motion may stimulate the colony formation in green algae, cul^are experiments were conducted under axenic conditions in a circular water chamber where the flow rate, temperature, light, and nutrients were controlled. The number of cells of Microcystis aeruginosa, the number of cells per colony, and the colonial characteristics in various growth phases were observed and measured. The results indicated that the colony formation in Microcystis aeruginosa, which was not observed under stagnant conditions, was evident when there was fluid motion, with the number of cells per largest colony reaching 120 and the proportion of the number of cells in colonial form to the total number of cells and the mean number of cells per colony reaching their peak values at a flow rate of 35 crn/s. Based on the analysis of colony formation process, fluid motion stimulates the colony formation in Microcystis aeruginosa in the lag growth phase, while flushes and disaggregates the colonies in the exponential growth phase. The stimulation effect in the lag growth phase may be attributable to the involvement of fluid motion in a series of physiological processes, including the uptake of trace elements and the synthesis and secretion of polysaccharides. In addition, the experimental groups exhibiting typical colonial characteristics in the lag growth phase were found to have higher cell biomass in the later phase.
