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831.
The growth and alkaline phosphatase activity(APA) of two raphidophyceae species Chattonella marina and Heterosigma akashiwo were investigated in response to P-limitation and subsequent addition of dissolved inorganic phosphorus(DIP, Na H2PO4) and two dissolved organic phosphorus(DOP) compounds: guanosine 5-monophosphate(GMP) and triethyl phosphate(TEP). APA levels increased greatly after P-starvation as the decrease of the cellular phosphorus quotes(Qp). C. marina responded to P-limitation quickly and strongly, with 10-fold increase in APA within 24 hr after P-starvation. The larger difference between maximal and minimal QP values in C. marina indicated its high capacity in P storage. APA of H. akashiwo was maximally enlarged about 2.5 times at 48 hr of P-starvation. After the addition of nutrients, cell numbers of C. marina increased in all treatments including the P-free culture, demonstrating the higher endurance of C. marina to P-limitation. However, those of H. akashiwo increased only in DIP and GMP cultures. APA increased only after the addition of the monophosphate ester GMP. The results suggest that quick responses of C. marina to P-limitation, high capacity in P storage as well as endurance for P-depletion provide this species an ecological advantage in phytoplankton community competition under DIP-limited conditions. 相似文献
832.
Junxia Li Zipeng Dong Yiyu Li Junmei Yang Xingang Liu Liang Yuan Yan Yin Zhanqing Li Peiren Li Gang Ren Lijun Jin Runjun Li 《环境科学学报(英文版)》2015,27(8):44-56
Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (σsc), absorption coefficients (σab), Angström exponent (α), single scattering albedo (ω), backscattering ratio (βsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc′) were obtained. The mean statistical values of σsc were 77.45 Mm− 1 (at 450 nm), 50.72 Mm− 1 (at 550 nm), and 32.02 Mm− 1 (at 700 nm). The mean value of σab was 7.62 Mm− 1 (at 550 nm). The mean values of α, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Qsc and Qsc′ showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Qsc, Qsc′, σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions. 相似文献
833.
长江流域沉积物中黑碳分布及其与多环芳烃的相关性研究 总被引:1,自引:0,他引:1
本文采用CTO-375法测定了长江流域主流及直流20个表层沉积物中黑碳的含量,探讨了沉积物中黑碳与粒度、总有机碳以及多环芳烃之间的关系。结果表明,长江流域沉积物中黑碳的含量范围在0.22~1.89mg/g之间,与粘土、粉砂及砂含量之间的相关性并不明显,说明粒度组成并不是控制BC分布的主要因素。BC与TOC之间的显著正相关性,表明BC与TOC有相似的来源,如人类活动、土壤流失。沉积物中BC与PAHs有较好的相关性,表明二者之间有相似的来源,同时也表明PAHs在研究区域沉积物中吸附主要由BC控制,这为研究多环芳烃在长江流域的环境归趋与影响因素等提供了新的信息。 相似文献
834.
This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water,and thermal modification were investigated. The results showed that thermal activation at 800℃ for 1 hr was the optimum operation to improve the adsorption capacity. The adsorption process of the thermally modified slag was well described by the Elovich kinetic model and the Langmuir isotherm model. The maximum adsorption capacity calculated from the Langmuir model reached 13.62 mg/g. Scanning electron microscopy indicated that the surface of the modified slag was cracked and that the texture became loose after heating. The surface area and pore volume did not change after thermal modification. In the treatment of domestic wastewater, the modified slag bed(35.5 kg) removed phosphate effectively and operated for 158 days until the effluent P rose above the limit concentration of 0.5 mg/L. The phosphate fractionation method, which is often applied in soil research, was used to analyze the phosphate adsorption behavior in the slag bed. The analysis revealed that the total contents of various Ca–P forms accounted for 81.4%–91.1%, i.e., Ca10–P 50.6%–65.1%, Ca8–P 17.8%–25.0%,and Ca2–P 4.66%–9.20%. The forms of Al–P, Fe–P, and O–P accounted for only 8.9%–18.6%. The formation of Ca10–P precipitates was considered to be the main mechanism of phosphate removal in the thermally modified slag bed. 相似文献
835.
应用SEM-EDS结合XRF法测定了2013年8月-2014年5月昆山市7个不同地区大气PM2.5中无机元素的污染水平。研究发现,昆山地区一共可检出40种无机元素,其中主要的22种元素浓度范围在3.02~1113 ng/m3之间,合计为3784 ng/m3;PM2.5中无机元素季节变化明显,呈现春秋季高,夏冬季低的变化特点。无机元素的空间变化不大。通过富集因子的研究,Sc、Ni、Cu、Zn、As、Br、Cd、Pb、Se、Ag、Sn、Sb和Tl等13种元素EF>10,富集程度非常高,说明人类活动对这些元素的贡献较大。 相似文献
836.
呼伦贝尔市环境监测站对呼伦湖多年水质监测的数据,通过进行统计分析后显示:近10年,呼伦湖水质为劣V类,重度污染,水体富营养化较严重,富营养化程度呈逐年加重趋势.主要污染物总磷、氨氮、氟化物、高锰酸盐指数、化学需氧量以及水体营养状态指数与周围地区同期降水量相关性分析结果显示:该湖主要污染物、水体营养状态指数与周围地区同期降水量无相关,湖水水质优劣与富营养化程度不完全由其周围地区降水量决定.根据呼伦湖具体情况分析其重度污染、中度富营养化的原因,并针对污染来源提出防治对策建议. 相似文献
837.
838.
浙江省缺乏常规能源,在能源结构中,火电比重已经过大,加快核电发展,是我省电力发展的必然选择。继中国第一座自行设计、建造的核电站--秦山核电站之后,浙江省第二座核电站三门核电站的两台目前国内最先进的百万千瓦级压水堆技术机组也即将在2015年投入运营。加速核电建设不仅保证能源安全、调整能源结构,而且能实现节能减排、减少环境污染,建设环境友好型、资源节约型社会、推动经济社会又好又快发展。我省核电建设应通过加强核电站的安全检查、设计建设中安全措施保障、解决核电建设存在的相关问题和加强监测网络的建设等,促进浙江省的核电建设与环境安全协调发展。 相似文献
839.
中国流域水资源管理立法研究 总被引:1,自引:0,他引:1
由于人们对流域水资源的肆意掠夺和无情盘剥,流域生态系统日趋退化,资源衰竭、环境污染,己经成为制约人类社会经济可持续发展的瓶颈。事实证明,国外经过多年的实践探索已经成功找到适合流域水资源管理的机制,然而,由于中国流域水资源管理立法的滞后性,中国流域水资源管理现状不容乐观。因此,我们应该在借鉴国外先进经验的基础上,完善中国流域水资源管理的立法,力求建立健全流域水资源管理的法律体系,以求更好地实现流域水资源管理。 相似文献
840.