用TN-TP-SRSi三角形图解评价藻类组成结构的营养比动力学     

Katrin Teubner  Thomas Teubner 《湖泊科学》1998,10(S1):393-410

To show the relative availability of nitrogen, phosphorus and silica for diatoms as well as non-siliceous algae in phytoplankton communities triangular diagrams are most appropriate. Triangular diagrams for TN-TP-SRSi show the nutrient ratios TN:TP, SRSi:TN and SRSi:TP in proportion to each other at the same time.Comparison of waters, grouped according to their limnological characteristics, indicate that these groups have also different seasonal dynamics of TN, TP and SRSi in proportion to each other. From these groups, which include meso-eutrophic and hypertrophic, shallow and deep, polymictic and dimictic lakes,only the group of "flushed, hypertrophic polymictic lakes" has a high seasonal dynamic of the ratios of all three macronutrients. Moreover the relative availability of TN:TP-ratios changes from > 16:1 in spring to <16:1 in summer. Significant changes in phytoplankton structure are associated with this high dynamic of the nutrient ratios. Considerable changes in the share of cyanobacteria to diatom biomass during summer are synchronised with a powerful modification of the relative availability of TN-TP-SRSi as illustrated by the triangular diagrams.For practical purposes trophic situations are most commonly evaluated from concentrations of a single nutrient or a nutrient ratio, such as N:P. However, a complex assessment would often be more appropriate. In this context triangular diagrams have the benefit of synoptically presenting relative nutrient availability for phytoplankton communities as a whole.  相似文献   

表层海水硅同位素的分布特征及其影响因素     

倪建宇  付锋  王渊  姚旭莹 《海洋学报》2021,(2):1-8

本文分析了采集自太平洋、印度洋和大西洋的表层海水溶解硅酸盐的δ30Si值,结果表明,太平洋表层海水的δ30Si值为0.45‰～2.91‰,平均值为(1.52±0.59)‰;印度洋表层海水的δ30Si值为0.98‰～2.30‰,平均值为(1.52±0.36)‰;大西洋表层海水的δ30Si值为0.90‰～2.23‰,其平均值为(1.55±0.35)‰。硅同位素在各大洋表层,主要表现出与大洋表层环流和经向翻转流的相关性,其分布特征受表层水体中的生物活动以及表层洋流运动导致的不同水团之间的混合的影响,且混合作用可能对开放大洋表层水体的δ30Si分布具有显著的影响。  相似文献   

Solar light, seawater temperature, and nutrients, which one is more important in affecting phytoplankton growth？   总被引：2，自引：1，他引：1  

苗振清  杨东方 《中国海洋湖沼学报》2009,27(4):825-831

Based on research results on the impacts of solar light, seawater temperature, and nutrient available to phytoplankton growth and changes in phytoplankton physiology and assemblage, we discussed the order of influence of these factors. By clarifying the mechanisms and processes of the impacts by these factors, we have determined the rising order of the importance as solar light, seawater temperature, and nutrient silicon (Si). Therefore, for human interests in sustaining economic development, the first thing to be considered is the input of nutrient Si into the ocean, followed by seawater temperature change.  相似文献   

Nutrient regimes and their effect on distribution of phytoplankton in the Bay of Bengal     

Paul JT  Ramaiah N  Sardessai S 《Marine environmental research》2008,66(3):337-344

The seasonal dynamics of nutrient ratios and abundance of phytoplankton cells from the central (CB) and western (WB) Bay of Bengal (BOB) were studied during the fall intermonsoon (FIM; September-October 2002) and spring intermonsoon (SpIM; April-May 2003). The nutrient molar ratios of macronutrients such as nitrate to phosphate (N:P), nitrate to silicate (N:Si) and silicate to phosphate (Si:P) in the top 120m were calculated for both FIM and SpIM. During both the seasons, the N:P ratios along the CB and WB were lower than 16, indicating nitrate deficiency. Whereas, along both transects the N:Si ratio was <1 and Si:P >3 in the top 20 and 40m during FIM and SpIM, respectively, indicating Si enrichment. Relatively greater nutrient concentrations along the WB than the CB appear to contribute to higher phytoplankton abundance. The preponderance of diatoms in the Bay could be attributed to rapid utilization of available nutrients in particular during FIM thus resulting in low N:Si ratios in the water column. Among diatoms, pennales were predominantly controlled by nutrients and their ratios. While, apart from nutrients, physical stratification, light and eddies also seem to influence the distribution and abundance of centrales.  相似文献   

Silicon limitation on primary production and its destiny in Jiaozhou Bay, China——Ⅶ： The complementary mechanism of the earth ecosystem     

杨东方高振会  杨应斌孙培艳 王鑫平 《中国海洋湖沼学报》2006,24(4):401-412

1 INTRODUCTION In marine waters, water temperature and nutrient Si control the temporal and spatial variation of the phytoplankton growth (Yang et al., 2006). The effect of nutrient Si and water temperature on the mecha- nism of phytoplankton growth has p…  相似文献   

高精度硅同位素分析方法研究进展     

王俊霖  王微  魏海珍 《高校地质学报》2021,27(3):275-288

基于碱熔法的改进和多接收电感耦合等离子质谱仪（MC-ICP-MS）的发展,近年来高精度Si同位素组成（δ30Si）分析方法取得了长足进步,分析精度（2SD）自气体质谱仪（GS-MS）时代的±0.15‰~±0.30‰ 提高到优于±0.10‰,足以辨析高温过程中Si同位素发生的微小分馏,并且避免了实验流程中使用含氟等危险化学品。二次离子质谱（SIMS）和飞秒激光剥蚀（fs LA）的发展使得原位Si同位素组成分析精度近期也优化到±0.10‰~±0.22‰。文章对近年来Si同位素分析方法的发展沿革进行综述,探讨建立溶液法MC-ICP-MS的高精度Si同位素分析方法的进展与局限,并比对了国内外各个实验室已发表国际国内Si同位素标准物质测定值,最后总结了硅酸盐地球（BSE）、地壳和陨石等主要地质储库的δ30Si组成范围。  相似文献   

Increasing eutrophication in the coastal seas of China from 1970 to 2050   总被引：4，自引：0，他引：4  

Maryna Strokal  He Yang  Yinchen Zhang  Carolien Kroeze  Lili Li  Shengji Luan  Huanzhi Wang  Shunshun Yang  Yisheng Zhang 《Marine pollution bulletin》2014

We analyzed the potential for eutrophication in major seas around China: the Bohai Gulf, Yellow Sea and South China Sea. We model the riverine inputs of nitrogen (N), phosphorus (P) and silica (Si) to coastal seas from 1970 to 2050. Between 1970 and 2000 dissolved N and P inputs to the three seas increased by a factor of 2–5. In contrast, inputs of particulate N and P and dissolved Si, decreased due to damming of rivers. Between 2000 and 2050, the total N and P inputs increase further by 30–200%. Sewage is the dominant source of dissolved N and P in the Bohai Gulf, while agriculture is the primary source in the other seas. In the future, the ratios of Si to N and P decrease, which increases the risk of harmful algal blooms. Sewage treatment may reduce this risk in the Bohai Gulf, and agricultural management in the other seas.  相似文献   

Uranium Behavior in the Process of Primary Pitchblende Ores Alteration by the Post‐ore Hydrothermal Solutions: An Application to Assessment of Uranium Migration from Underground Spent Nuclear Fuel Repositories     

Nikolay P. Laverov  Vasily I. Velichkin  Ai Fujiwara  Naotatsu Shikazono  Alexey P. Aleshin  Enver E. Asadulin  Vyacheslav N. Golubev  Tatiana L. Krylova  Alexander A. Pek  Igor V. Chernyshev 《Resource Geology》2009,59(4):342-358

It has been shown that the main uranium ore mineral, pitchblende (uranium dioxide), is a natural analog of synthetic uraninite (also uranium dioxide), which constitutes 96% of spent nuclear fuel (SNF). Geochronological studies of the U‐Pb isotope systems in unaltered pitchblende from the orebodies reveal that these systems remained completely closed over the entire period (approximately 135 Ma) since the formation of the deposits. The bulk of the primary uranium ores within the Streltsovskoye ore field was influenced to various degrees by post‐ore hydrothermal solutions that led to pitchblende spherulites being replaced by pseudomorphs of an amorphous phase with a U‐Si composition; this phase also re‐precipitated in veinlets proximal to the pitchblende pseudomorphs. A technique specially developed by the authors was used to carry out quantitative counts of the abundance of uranium minerals by calculating the uranium mass balance in one of the orebodies subjected to hydrothermal alteration. The calculations reveal minimal uranium loss from the orebody. Uranium liberated in the process of the pseudomorphic replacement of pitchblende was immediately fixed, in situ, in the newly formed coffinite‐like amorphous U‐Si phase as a result of the development of an efficient geochemical barrier that prevented the long‐distance migration of uranium. In assessing the long‐term safety of underground SNF repositories, the results of the present study give us confidence that SNF uraninite, in terms of the preservation of its integrity as a mineral phase, provides for the reliable long‐term isolation of uranium, transuranium elements, and fission products that are “sealed” in the uraninite matrix. In the case of the mineral transformation of the uraninite matrix by hydrothermal solutions, the liberated uranium would be efficiently immobilized by the newly formed amorphous U‐Si phase.  相似文献   

断裂带中硅的化学活动类型和变质平衡系统     

孙岩  万玲 《高校地质学报》1996,2(1):38-47

我国东北地区数十条断裂带横剖面上断层岩的化学分析资料表明，硅含量的递变有是 规律。从变质作用，成分组合、显微构造、分带分异和构造背景等的不同表现，元素硅持球化学行为可分为低级变质作用和甚低级变质作用两咱类型。硅在断裂带中变化的复杂性，依实例分析为低级变质作用和甚低级变质作用两种类型。硅在断裂带中变化的复杂性，依实例分析同长石的分解密切相关，此系动力分异的一所导致的变质分异和化学分异多次性的结果，并  相似文献   

Computational study of tetrahedral Al–Si ordering in muscovite     

E. J. Palin  M. T. Dove  S. A. T. Redfern  A. Bosenick  C. I. Sainz-Diaz  M. C. Warren 《Physics and Chemistry of Minerals》2001,28(8):534-544

 The nature of Al–Si ordering across the tetrahedral sites in muscovite, K₂Al₄(Si₆Al₂O₂₀)(OH)₄, was investigated using various computational techniques. Values of the atomic exchange interaction parameters J _l were obtained. From these parameters, a two-dimensional Al–Si ordering scheme was deduced. The transition temperature T _c for this two-dimensional ordering is 1900 K. There are several possible ordering schemes in three dimensions, based on different stacking sequences of ordered sheets of tetrahedral sites. Monte Carlo simulations of both two-dimensional and three-dimensional ordering were performed, but in the three-dimensional simulation only the two-dimensional ordering is seen, implying that three-dimensional ordering is too slow to be attained during the timescale of the simulation. The effect of the three-dimensional interactions is to raise the two-dimensional ordering temperature to 2140 K. From the three-dimensional Monte Carlo simulation, the frequency of occurrence of 4Si0Al, 3Si1Al, 2Si2Al and 1Si3Al clusters was determined, which match those inferred by ²⁹Si MAS–NMR measurements reasonably well. In fact, the match suggests that the cation ordering seen in experiments corresponds to a configuration with considerable short-range order but no long-range order, similar to a state that is at a temperature just above an ordering phase transition. Received: 28 August 2000 / Accepted: 12 March 2001  相似文献