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31.
Behavior of different phosphorus species in suspended particulate matter in the Changjiang estuary 总被引:1,自引:0,他引:1
Suspended particulate matter (SPM) collected in the Changjiang (Yangtze River) estuary in June 2006 was separated into five
fractions via water elutriation: clay-very fine silt (<8 μm), fine silt (8–16 μm), medium silt (16–32 μm), coarse silt (32-63
μm) and sand (>63 μm). The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction
method to obtain six species of phosphorus: exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital
P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated
to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth
to the gate of the river mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount
of exchangeable P appeared around the gate of the river mouth. From the gate of the river mouth to the sea, exchangeable P
and organic P in suspended particles increased distinctly. The total particulate P flux into the estuary from the Changjiang
River was about 45.45×108 μmol/s during sampling. Of this, about 8.27×108 μmol/s was associated with the “truly suspended” fraction. The bio-available particulate P flux was about 13.58×108 μmol/s. Of this, about 4.24×108 μmol/s was transported by “truly suspended” particles. 相似文献
32.
Species and distribution of inorganic selenium in the Bohai Sea 总被引:1,自引:0,他引:1
1 INTRODUCTION Selenium is a ubiquitous trace element that ex- ists in multiple chemical forms in seawater in dif- ferent oxidation states and organic metalloid com- pounds. Selenium is essential for the growth of various photosynthetic species in natural… 相似文献
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长江口及邻近海域沉积物再悬浮对水体磷酸盐的影响的模拟研究 总被引:3,自引:1,他引:2
以长江口及邻近海域为研究区域,采用改进后的SEDEX法对沉积物中各形态磷的含量进行了分析,并通过模拟实验探讨了沉积物再悬浮对上覆水体磷酸盐浓度的影响。结果表明:碎屑磷(De-P)是沉积物磷的主要赋存形态,占总磷(TP)的50%以上;其次是可提取态有机磷(Or-P)和非活性有机磷(Re-P);生物可利用磷(BAP)占总磷的比例约为21%,可提取态有机磷(Or-P)是生物可利用磷(BAP)的主要存在形态。沉积物再悬浮时,水体磷酸盐的浓度显著升高,说明沉积物再悬浮会引起沉积物中磷的释放;水体磷酸盐浓度升高主要源于沉积物中磷的释放,而间隙水的贡献较低。沉积物发生再悬浮时,厌氧条件相对于好氧条件,更有利于沉积物磷的释放。 相似文献
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Relationships between phytoplankton community composition and environmental variables in the East China Sea (ECS) and Yellow
Sea (YS) were investigated using geochemical and molecular microbiology methods. The diversity of phytoplankton was characterized
using cultivation-independent PCR-based denaturing gradient gel electrophoresis (DGGE). Groups resulting from unweighted pair-group
method with arithmetic averages clustering of the DGGE profiles showed good consistency with the eco-environmental characteristics
of the sea area they belonged to. Additionally, the clustering results based on DGGE fingerprinting and those based on morphological
compositions were practically identical. The relationship of phytoplankton diversity to environmental factors was statistically
analyzed. Temperature, dissolved inorganic nitrogen (DIN), and silicate-Si were found significantly related to the phytoplankton
community composition. Canonical correspondence analysis (CCA) was performed to reveal the relationship between community
composition and these three environmental factors. Generally, values of the ECS are clearly separated from those of the YS
in the CCA biplot, due to mainly the effect of temperature and DIN. 相似文献
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于特枯水情年对三峡水库溶解硅和长江干流自涪陵至河口段悬浮颗粒物、溶解硅、生物硅和叶绿素a浓度等进行调查.研究表明,在平水期和汛期末,长江干流水体溶解硅和生物硅浓度和通量在其上游受大坝"滞留"效应的影响呈现沿程降低的趋势,中、下游受"两湖"和汉江等的补充作用有明显升高.在枯水年,长江干流水体生物硅浓度占活性硅(溶解硅和生物硅之和)浓度的2%~5%,显著低于平水年的比例(13%),同时也低于世界河流的平均水平(16%).三峡水库在4-12月份减少溶解硅向下游的输送通量,而在1-3月份增加溶解硅的输送通量;水库在枯水年滞留了大约3%~6%的溶解硅.三峡水库内低的初级生产水平和高的生物硅再生速率是其难以对溶解硅形成有效滞留的主要因素.大坝下游会因清水下泄产生潜在的滞留效应,不过还需要更多的数据去量化. 相似文献
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于2006年6月和2007年4月在长江口及毗邻海区采集了表层沉积物样品,利用水淘选法对沉积物进行了粒径分级,并采用改进后的SEDEX方法对沉积物样品及分粒级沉积物样品进行了磷形态分析。结果表明,2006年6月和2007年4月长江口及毗邻海区沉积物总磷变化分别为12.56~19.64μmol/g和8.99~19.91μmol/g,其中碎屑磷是磷的主要存在形态。可交换态磷、铁结合态磷、有机磷、自生磷灰石磷及难分解有机磷在长江口外的平面分布比较一致,均在紧邻长江口门外、杭州湾外的条状带出现了含量的高值,而在口门内及口门外河口靠海一侧碎屑磷含量较高。不同形态磷在不同粒径沉积物中的含量不尽相同:有机磷、自生磷灰石磷以及难分解有机磷是小于8μm粒级沉积物中磷的主要组成部分,而且其在总磷中所占比例随沉积物粒径的增加而下降;碎屑磷则主要集中在粗沉积物中,为32~63μm及大于63μm粒级沉积物中磷的主要贡献者。沉积物的粒度分异以及各形态磷在不同粒径沉积物中含量的差异,共同影响着河口沉积物中磷的分布。 相似文献