中国科学院水生生物研究所机构知识库
Advanced  
IHB OpenIR  > 中科院水生所知识产出(2009年前)  > 学位论文
题名: 东湖沉积物磷形态、行为及生态学意义
作者: 付永清
答辩日期: 2000
导师: 周易勇
授予单位: 中国科学院水生生物研究所
授予地点: 中国科学院水生生物研究所
学位: 硕士
关键词: 东湖沉积物 ; 磷形态 ; 行为 ; 生态学意义
摘要: 磷作为水体初级生产力的限制因子,决定了磷循环在水体生态系统中的重要作用。磷循环可分为生物循环和地球化学循环,前者许多过程已为人揭示,而与后者相联系的诸多过程的研究进展相当缓慢。沉积物磷组分的复杂性、多种环境因子对磷形态、行为影响的交互作用导致了这一状况。这无疑成为认识湖泊磷循环的一大瓶颈。本文以富营养化的东湖为研究对象,试图阐明其中一二。主要研究结果如下:1、经典提取法和EDTA提取法分级分离东湖沉积物磷的结果均表明,铁结合态磷是沉积物磷的主要存在形态,占沉积物总反应性磷(TRP)的70%左右。经典提取法中,NH_4Cl提取的易交换性或松结合态磷占TRP的3-7%,高于水提取的量(<3%)。在富营养化程度较高的I站,这种形态的磷的含量明显高于II、III两站。碳酸氢钠一连二硫酸钠提取的反应性磷(BD-RP)和NaOH提取的反应性磷(NaOH-RP)之和占TRP的57-81%。这两种形态的磷主要与铁结合,在东湖磷循环中意义重大。EDTA提取法较好地避免了提取过程中磷的重吸附,铁结合态磷和钙结合态磷的含量一般高于由经典提取法相应步骤测得的含量。沉积物各形态的磷表现出一定的季节变化规律,总的说来,沉积物TRP按I、II、III站的次序依次递减,分别为1650、1 048、730 μg.g dw~(-1)(以1998年10月样品测定结果计,dw表示干重)。沉积物中铁结合态磷与钙结合态磷的比率可用来评判湖泊富营养化的程度,一般而言,高比率预示着较高富营养化水平。在富营养化程度最高的东湖I站,这一比率明显高于II、III站,以4月份经典提取法的测定结果来看,这一比率依次为80:10,75:11和75:14。2、在沉积物磷分级界定的基础上,以磷吸附指数(PSI)和平衡磷浓度(EPC)来研究正磷酸盐在东湖沉积物一水界面的可能行为模式。结果表明,铁结合态磷的含量与EPC正相关,而与PSI负相关。I站沉积物吸附磷能力明显不及II、III两站。在影响沉积物PSI或EPC的诸多环境因子中,上覆水钙浓度、pH及沉积物粒径组成起重要作用,而温度、沉积物生物因子等影响不大。沉积物对磷的吸附可能主要与沉积物交换性铁的介入有关。吸附曲线能由Freundlich方程:P_(sed)=A~*(o - P_w)~B很好拟合(r > 0.95)。PSI随钙浓度上升而增大,PSI的高峰值出现在pH5.8附近,此时沉积物表现出最大吸磷能力。沉积物颗粒越细,吸附磷的能力越强(即PSI越大);I站沉积物颗粒细小的组分(<0.075mm)含量最高,但其PSI最小,这与其有效吸附位点的减少有关。尽管II、III两站沉积物PSI高于I站,但总的说来,东湖沉积物的高EPC和低PSI值说明,沉积物对磷的吸附控制能力正在日益弱化。3、东湖各站表层沉积物中可为碱性磷酸酶降解的磷(PHP)具明显的季节变化规律:从3月份开始,沉积物PHP的含量锐减,5-9月份近于耗尽,1O月以后出现积累。东湖沉积物PHP在藻类繁盛季节,可提供数量可观的磷。在东湖I站,由沉积物表层到35cm深处,沉积物有机磷中的PHP可占到O-1 0%以上。在研究期间(1999年5月)沉积物间隙水中PHP与O-P的比值在O-0.3范围内。以o-P和PHP(葡萄糖-1-磷酸盐和肌醇单磷酸盐)分别测定沉积物EPC,结果表明,EPC均随沉积物深度的增加而下降(吸附o-P和PHP的能力递增),在28-35cm处EPC值趋于一致,约43.Oμg P l~(-1)。沉积物对PHP的吸附机制不同于对o-P的吸附。沉积物碱性磷酸酶活性(APA)在表层最大,且随深度的增加而下降。沉积物APA与铁结合态磷(Fe(OOH)≈P)、酸可溶态有机磷(ASOP)和总反应性磷(TRP)正相关。ASOP中有部分磷可能是沉积物APA作用的底物。在沉积物表层(O-7cm)和中部(14-21cm),由APA介导的PHP降解作用可能较为强烈,这对沉积物磷循环意义重大:沉积物底部的有机磷部分可降解为o-P并释放至水柱中,参与到磷的再循环过程。
英文摘要: As one important limiting factor of primary production, phosphorus plays a significant role in nutrient cycling in aquatic ecosystems. For the sake of convenience, P cycling was divided into two aspects: the biological cycling and the geochemical cycling. Processes associated with the former one are now fairly well understood while processes in the latter are very slow, especially the solution of sediments. This unsatisfactory status, due to the complexity of sediment P species as well as the environmental multi-effects on P behavior, is undoubtedly an obstacle for the understanding of P cycling in aquatic bodies. This paper is aimed to elucidate some respects involved with P cycling in sediments via relevant studies on a eutrophic lake - Lake Donghu. The main results are as following: 1. Sediment P species were fractionated with classic method and EDTA-method respectively. Results showed that iron-bound P were the main species in sediments and constituted about 70% of total reactive phosphorus (TRP) . With the classic method (Psenner et al., 1985), approximately 3-7% of TRP was labile or exchangeable P extracted by NH_4Cl, more than that extracted by water (<3%). At the most eutrophic Station I, content of this kind of P was markedly higher than that at less enriched Station II and III. Iron-bound P, successively extracted by NaHCO_3-Na_2S_20_4 (BD-RP) and NaOH (NaOH-RP), accounted for 57-81% of TRP. As the EDTA-method can well avoid P re-adsorption during extraction, the amounts of iron-bound and calcium-bound P were higher than those extracted by the classic method. There was a seasonal variation in sediment TRP concentration during the study period and as a whole, sediments at Station I had the largest TRP content: the value was 1650 μg.g dw~(-1), much more than those at station II (1048 μg.g dw~(-1)) and III (730 μg.g dw~(-1)) based on the study of samples collected in October 1998. The ratio of iron-bound P: calcium-bound P could be used as an indicator for evaluating lake eutrophication and the higher the ratio, the higher level of eutrophication. At Station I, this ratio was usually larger than that at Station II and III, for example, the ratios were 80:10, 75:11 and 75:14 respectively based on the samples collected and analyzed in April 1998 according to the classic method. 2. The likely behavior of P at the sediment-water interface was studied by determining the phosphorus sorption index (PSI) and equilibrium phosphorus concentration (EPC) along with the influencing factors. Results showed that EPC was positively while PSI negatively correlated with iron-bound P. The P adsorption capacity of sediments at Station I was much lower than that at Station II and III. Among the likely factors that affected the adsorption, Ca concentration of overlying water, pH and sediment particle size were the main ones while the effects of temperature and biological factor were minor. The P adsorption process was in accordance with a mechanism involving the presence of hydrolyzed exchangeable Fe. The adsorption isotherms can be well fitted by Freundlich equation: P_(sed) = A~*(o - P_w)~B. PSI increased with increasing pH and the maximum occurred at approximate pH5.8 where the adsorption capacity was the largest. Finer sediments exhibited greater PSI or lower EPC than coarser sediments and sediments at Station I showed the lowest PSI or highest EPC values in spite that more than 45% of the sediment fraction was within the finest range (<0.075 mm). This might attribute to the lesser available sorption sites in the sediments at Station I, compared with those at Station II and III. 3. Phosphatase hydrolyzable phosphorus (PHP) is a significant kind of organic phosphate that can be utilized by organisms with the action of alkaline phosphatase. Study on annual variation in sediment PHP suggested that PHP in Lake Donghu contributed a considerable quantity of P to phytoplankton during algal bloom in summer and fall: declining markedly from March, sediment PHP were nearly depleted from May through September and then accumulated in the following months. Sediment PHP at Station I or II was usually higher than that at Station III, the less enriched region. Down from the surface to 35 cm deep at Station I, PHP constituted 0 to over 10% of sediment organic P pool during study period. Ratio porewater PHP: porewater o-P was in the range of 0-0.3. Laboratory sorption experiments showed that sediment EPC declined with depth for both o-P and PHP (exemplified by G-1-P and IMP), approaching almost a same value (about 43.0 μg P 1~(-1)) at the 28-35 cm layer. Different mechanisms might be responsible for the adsorption of o-P and PHP onto sediments. Sediment alkaline phosphatase activity (APA) was positively correlated with the amount of iron-bound P, acid soluble organic P and TRP. Sediment APA decreased with increasing depth, suggesting the phosphatase-induced PHP hydrolyzation or phosphorus regeneration could occur intensively at the sediment-water interface. The relatively low concentration of porewater/sediment PHP and high APA at the middle stratum (14-21 cm) implied another active P regeneration area. These two areas were of important limnological implications: sediment PHP, especially from the deeper layer, as a P pool, could be hydrolyzed to o-P and released into water column and then incorporated into P cycling.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.ihb.ac.cn/handle/342005/12560
Appears in Collections:中科院水生所知识产出(2009年前)_学位论文

Files in This Item:
File Name/ File Size Content Type Version Access License
LW005047.pdf(1924KB)----暂不开放-- 联系获取全文

Recommended Citation:
东湖沉积物磷形态、行为及生态学意义.付永清[d].中国科学院水生生物研究所,2000.20-25
Service
Recommend this item
Sava as my favorate item
Show this item's statistics
Export Endnote File
Google Scholar
Similar articles in Google Scholar
[付永清]'s Articles
CSDL cross search
Similar articles in CSDL Cross Search
[付永清]‘s Articles
Related Copyright Policies
Null
Social Bookmarking
Add to CiteULike Add to Connotea Add to Del.icio.us Add to Digg Add to Reddit
所有评论 (0)
暂无评论
 
评注功能仅针对注册用户开放,请您登录
您对该条目有什么异议,请填写以下表单,管理员会尽快联系您。
内 容:
Email:  *
单位:
验证码:   刷新
您在IR的使用过程中有什么好的想法或者建议可以反馈给我们。
标 题:
 *
内 容:
Email:  *
验证码:   刷新

Items in IR are protected by copyright, with all rights reserved, unless otherwise indicated.

 

 

Valid XHTML 1.0!
Copyright © 2007-2017  中国科学院水生生物研究所 - Feedback
Powered by CSpace