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Lake sediment and overlying water Speciation and Distribution of Nitrogen and Phosphorus

Author: LinYueZuo
Tutor: DengNanSheng
School: Wuhan University
Course: Environmental Science
Keywords: Donghu Nutrient salt Phosphorus Nitrogen Morphological analysis Sediments Eutrophication
CLC: X524
Type: Master's thesis
Year: 2005
Downloads: 709
Quote: 14
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Abstract


Wuhan East Lake is a representative urban shallow lakes. Due to the impact of human activities in recent years, serious eutrophication. To fully understand, assess, predict and control the East Lake, the critical need to understand Lakes nutrients (nitrogen and phosphorus) in the water and sediments and variations on existing state. Based on past domestic eutrophic lakes and the lack of background research gaps in 2004-2005 using the site investigation, laboratory testing and distribution methods such as chemical analysis, on the southwestern part of the Donghu Lake, a sub - Lake Temple sediment cores and overlying water column nitrogen and phosphorus speciation analysis conducted its profile distribution, occurrence and characteristics, seasonal changes and the relationship between each factor carried out a systematic investigation. The main conclusions are as follows (1) overlying water and nutrient variation Occurrence: total nitrogen content is low in summer and winter, spring and autumn high content; nitrate nitrogen content in the autumn highest nitrite nitrogen content reached the highest in the summer. Summer to autumn lake phosphorus content decreased, the upward trend in autumn to winter, winter to spring, and a downward trend. Phosphorus content in the lake in autumn minimum, and mainly particulate form. Spring lake total dissolved total phosphorus ratio is the highest in four seasons. (2) the occurrence of nitrogen sediment characteristics and variation: total nitrogen content in the vertical cross section showed deposition depth increases with decreasing trend; their content changes with the seasons are cyclical pattern: spring sediments TN content is at least a year, and began to increase in summer, autumn and winter maximum amount of nitrogen to the spring of the second year of the content and then down to the level of a year ago. TN and buried by sediments double impact of the environment, the average content of sediment ammonia and nitrogen seasonal variation similar content and only the second in the spring compared to the level a year ago there was a substantial increase. (3) various forms of phosphorus in sediments vertical Occurrence Characteristics: In the 0-10cm depth of deposition, total phosphorus (TP), no steady-state phosphorus (LP), iron phosphate (Fe-P) and aluminum phosphate (Al- P) has the obvious \Calcium (Ca-P), organic phosphorus (OrgP) and occluded phosphorus (OcP) with deposition depth variation complicated. (4) Lake sediment phosphorus forms in each of the average annual proportion of Fe-P gt; OrgP gt; OcP gt; Ca-P gt; Al-P gt; LP (5) the average content of phosphorus forms in sediments of the seasonal variation: Fall sediment phosphorus and iron phosphate reaches the maximum, while the occluded organic phosphorus and phosphorus to a minimum, correspond to the smallest total phosphorus content of water at this time, indicating that the fall is phosphorus sediment sinks. Organic phosphorus content in winter the maximum, corresponding to the total phosphorus content of the water in winter increased, indicating that a sediment

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Water pollution and its control > Lakes and reservoirs
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