太湖沉积物铁形态分布特征及磷铁相关性分析  

Distribution of iron forms and their correlations analysis with phosphorus forms in the sedimentary profiles of Taihu Lake

作　　者：杨文斌[1] 唐皓[1,2] 韩超[2] 丁士明[2] 

机构地区：[1]安徽师范大学环境科学与工程学院,安徽芜湖241003 [2]中国科学院南京地理与湖泊研究所,湖泊与环境国家重点实验室,江苏南京210008

出　　处：《中国环境科学》2016年第4期1145-1156,共12页China Environmental Science

基　　金：安徽省自然科学基金项目(1208085MD60);国家自然科学基金项目(31070338)

摘　　要：通过对太湖藻型湖区、草藻过渡型湖区、草型湖区柱状沉积物进行铁的形态分级分析沉积物中不同提取态磷铁含量,获得不同形态铁的空间分布特征.结果表明:沉积物总铁含量藻型湖区31.57mg/g(SD=8.51)>过渡型湖区30.34mg/g(SD=11.97)>草型湖区25.25mg/g(SD=4.59),不同湖区沉积物中铁形态的含量依次为可还原(晶型)铁氧化物Fe_(ox2)>碳酸盐铁Fe_(carb)>易还原(无定形)铁氧化物Fe_(ox1)>低活性硅酸铁Feprs>磁铁矿Femag>可吸附性Fe(Ⅱ),Fe_(carb)、Fe_(ox1)、Fe_(ox2),3种铁形态属于高活性铁Fe(III),含量为7.79,6.16,8.18mg/g,分别占总铁含量的28.56%,21.54%,29.53%,表明高活性铁(III)是沉积物中最主要的铁形态;沉积物中各提取态磷含量大小比较为NH_2OH·HCl-P>MgCl_2-P>NaAc-P>Na_2S_2O_4-P>浓HCl-P>(NH_4)_2C_2O_4-P,含量较高的MgCl_2-P(0.067mg/g)、NaAc-P(0.061mg/g)、NH_2OH·HCl-P(0.068mg/g),分别占总提取磷的35.28%、31.97%和22.55%,是沉积物铁分级提取态磷中最主要的形态.磷-铁相关性分析表明,二者之间呈显著的正相关(P<0.05),进一步从铁形态分级角度证实铁是沉积物內源磷释放的关键因子.Occureneces and distributions of iron forms in the sediment cores from three typically zones of Lake Taihu, i.e. phytoplankton dominated zone, macrophyte dominated zone, and phytoplankton-macrophyte transition zone, were investigated using the sequential extraction procedure. Generally, the total iron contents decreased in the order： phytoplankton dominated zone（31.57±8.51mg/g） phytoplankton- macrophyte transition zone（30.34± 11.97mg/g） macrophyte dominated zone（25.25±4.59mg/g）, while the contents of different iron forms in the interest sites followed the variations： reducible oxides Fe_（ox2）carbonate associated Fe Fe_（carb）easilyreducible oxides Fe_（ox1）poorly reactive sheet silicate Fe Feprsmagnetite FemagAbsorbed Fe（Ⅱ）, Fe_（carb）、Fe_（ox1）、Fe_（ox2） weremeasured to be7.79mg/g, 6.16mg/g, 8.18mg/g, accounting for 28.56%, 21.54%, 29.53% of total iron respectively, suggesting those highly reactive iron Fe（III） were the dominated iron forms. The concents of different extracted phosphorus in sediment decreased in the order： NH_2OH·HCl-PMgCl_2-PNaAc-PNa_2S_2O_4-PConcentrated HCl-P（NH_4）_2C_2O_4-P. Three dominated phosphorus fractions including MgCl_2-P、NaAc-P、NH_2OH·HCl-Pwere measured to be 0.067mg/g, 0.061mg/g, 0.068mg/g, accounting for 35.28%、31.97% and 22.55% of the total extracted phosphorus.Significantly positive relationships were observed between the extracted phosphorus and iron fractions using the sequential extraction（P0.05）, further confirming the concomitant release of phosphorus from reduction dissolution of Fe（oxyhydr） oxides in sediments.

关 键 词：铁形态分级 藻型湖区 草藻过渡型湖区 草型湖区 相关性分析 太湖 

分 类 号：X171[环境科学与工程—环境科学]