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81.
For some hundred surface sediment samples from five cores taken in two cruises near the Huanghe River Estuary, total phosphorus (TP (.inorganic phosphorus (IP (and organic phosphorus (OP)were determined.On the average, 527×10-6, 455×10~6 and 72×10-6 were found for TP,IP and OP for the surface sediments taken in the two cruises. The distribution of OP and IP was controlled by the sample particle size: OP content increased with the decreasing of the sample particle size, while the maximal value of IP was found in the silt fraction due to the existence of apatite in our samples. Vertical distributions reflected well the channel change of the Huanghe River. Results from the multiple regressions between the three forms of phosphorus and the percentages of different particle size agreed well with the analytical data.  相似文献   
82.
83.
提高生态浮床系统脱氮除磷效率研究进展   总被引:3,自引:0,他引:3  
生态浮床系统处理技术因具有投资少、易操作、无二次污染兼具良好景观性等优点而被广泛应用于各种类型污染水体的治理。生态浮床系统是一个复合生态工程系统,其对污染的去除机理是一个错综复杂的过程,填料、水生植物、水生动物和微生物共同发挥着重要作用。主要概述生态浮床系统的发展状况、脱氮除磷机理、限制因素及存在问题;重点概述以细菌固定化技术和曝气等方式的外在法和以改进生态浮床系统构造形式、筛选优势浮床植物等方式的内在法,来提高生态浮床系统脱氮除磷效率;展望了生态浮床污水处理系统未来的研究与应用前景。  相似文献   
84.
埃迪卡拉纪(震旦纪)陡山沱期是Rodinia超大陆裂离的重要地质时期,是多细胞生物起源和发展的重要转折时期和磷质聚集时期,也是化学、气候和环境变化的剧烈时期。液化岩脉、液化角砾岩、脉化变形构造、以及阶梯状层内断层等磷质震积岩的发现,表明扬子地区在陡山沱期晚期至少发生过两次以上的地震事件。地震构造运动将地球内部积累能量快速地释放,可能是磷质来源和热水活动一种重要的方式或通道。海水中磷等无机营养盐分的增加,海水温度的升高,有利于多细胞生物的起源和发展,同时多细胞生物的繁盛又有利于磷的聚集。  相似文献   
85.
Subsurface tile drainage speeds water removal from agricultural fields that are historically prone to flooding. While managed drainage systems improve crop yields, they can also contribute tothe eutrophication of downstream ecosystems, as tile-drained systems are conduits for nutrients to adjacent waterways. The changing climate of the Midwestern US has already altered precipitation regimes which will likely continue into the future, with unknown effects on tile drain water and nutrient loss to waterways. Adding vegetative cover (i.e., as winter cover crops) is one approach that can retain water and nutrients on fields to minimize export via tile drains. In the current study, we evaluate the effect of cover crops on tile drain discharge and soluble reactive phosphorus (SRP) loads using bi-monthly measurements from 43 unique tile outlets draining fields with or without cover crops in two watersheds in northern Indiana. Using four water years of data (n = 844 measurements), we examined the role of short-term antecedent precipitation conditions and variation in soil biogeochemistry in mediating the effect of cover crops on tile drain flow and SRP loads. We observed significant effects of cover crops on both tile drain discharge and SRP loads, but these results were season and watershed specific. Cover crop effects were identified only in spring, where their presence reduced tile drain discharge in both watersheds and SRP loads in one watershed. Varying effects on SRP loads between watersheds were attributed to different soil biogeochemical characteristics, where soils with lower bioavailable P and higher P sorption capacity were less likely to have a cover crop effect. Antecedent precipitation was important in spring, and cover crop differences were still evident during periods of wet and dry antecedent precipitation conditions. Overall, we show that cover crops have the potential to significantly decrease spring tile drain P export, and these effects are resilient to a wide range of precipitation conditions.  相似文献   
86.
Alkaline phosphatase activity (APA) and the availability of dissolved organic phosphorus (DOP) to marine algae were determined in Xiamen Bay and in algal batch culture systems. Results showed that APA changed with seasons, increasing to the highest value in summer and decreasing to the lowest in autumn and spring in Xiamen Bay. Tests on natural populations of planktonic algae and bacteria community showed that algae were mostly responsible for DOP utilization, while bacteria could not take up DOP compounds. Results from algal batch cultures also supported the above conclusion. Relationships between APA and environmental factors indicated that APA was negatively correlated with phosphorus level such as phosphate and small molecular DOP, and APA played an important role in utilization of DOP by algae. All the results emphasized the ecological significance of DOP in subtropical coastal waters.  相似文献   
87.
Bioassesment by the use of the macroalga, Ulva lactuca L., was carried out in the Limfjord, Denmark, to assess the significance of nitrogen and phosphorus as limiting factors for primary production during 1985, 1993, 1994 and 1995 and for the detection of changes in eutrophication levels.

Minimum and critical tissue concentrations for nitrogen and phosphorus in macroalgae were identified. The concentrations of nitrogen were generally below the critical concentration level in June–October in 1985, 1993, and 1995 but in 1994 nitrogen was only limiting for primary production in short periods. Only in early spring in 1985 and 1993 were the tissue concentrations of phosphorus below the critical concentration level, whereas in 1994 up to 3–4 months showed phosphorus limited growth, indicating that significant changes in limitation patterns can occur between different years.

It was concluded that the use of biomonitoring techniques is well suited as a bioassessment method for direct detection and for providing a time-integrated measure of nutrient availability in coastal waters, and thus for assessing ecosystem health with regard to eutrophication. It is recommended that biomonitors and the concept of critical tissue concentrations should be used in environmental management and incorporated in future monitoring programmes.  相似文献   

88.
海陆边缘沉积磷在全球变化研究中的意义   总被引:9,自引:1,他引:8  
从磷的生物地球化学循环的角度,讨论了磷与大气圈O2、CO2的关联模式,并通过研究磷的环境地球化学行为,揭示了海陆边缘沉积磷对古气候、古环境变化的记录及其对指示古全球变化的关键性,同时提出了中国东部沿海近代沉积磷的积累与全球变化的耦合作用关系,在中短时间尺度的全球变化研究中所具有的特殊意义。  相似文献   
89.
江西雅山花岗岩长石中磷的分布及意义   总被引:6,自引:0,他引:6  
刘昌实  黄小龙 《岩石学报》1999,15(2):291-297
雅山富氟高磷花岗岩具较高的全岩磷含量(0.15%~0.55%),长石是磷的主要赋存矿物,磷以PAlSi-2替换方式进入长石结构中。各种结晶习性的长石的磷含量各不相同。早世代钠长石和雪球结构中钠长石包裹体的结晶较早,平均磷含量分别为0.18%和0.19%,而晚世代钠长石和环带钾长石中钠长石嵌晶的结晶稍晚,具较高的平均磷含量(分别为0.25%和0.23%)。钾长石的磷含量相对于钠长石总体上较低,早期结晶的雪球结构主晶钾长石和环带钾长石的磷含量最低,分别为0.04%和0.02%,晚期细粒钾长石的平均磷含量略高(0.19%)。长石对全岩磷的贡献率还与磷锂铝石等磷酸盐副矿物是否达到饱和有关,当无磷锂铝石结晶时,长石磷的贡献率约为76%,反之则约为31%。  相似文献   
90.
厦门西港引发有害硅藻水华磷的阈值研究   总被引:12,自引:1,他引:11  
林昱  林荣澄 《海洋与湖沼》1999,30(4):391-396
1995年10月,在厦门市国家海洋局第三海洋研究所的陆基水池中,应用海洋围隔生态系实验技术,研究了在无海流、盐度等因子干扰的情况下,磷的形态、分布及其与浮游植物生物量的相关性。结果表明,海水中的可溶性无机磷(DIP)随时间里指数函数减少。浮游植物生物量主要与可溶性无机磷密切相关:[Chl-a]=A×e-B[PO4],这种相关的浮游植物生物量表现2d左右的滞后现象。还探讨了限制浮游植物增殖的DIP的最低浓度为0.3-04μmol/L,从DIP表现浓度估算浮游植物可能达到的最大生物量为[Chl-a]=10mg/m3,并由此估算出引发中肋骨条藻赤潮的DIP的阈值为1.2μmol/L,作为赤潮预测预报的参考。  相似文献   
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