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Studies on Nitrification and Its Influencing Factors of Liaohe Estuary Reed Wetland Sediments in Summer and Autumn of 2009

Author: ChenChunTao
Tutor: BaiJie
School: Ocean University of China
Course: Environmental Science
Keywords: Liaohe Estuary Wetland Sediment Nitrification Ammonia oxidizing bacteria ( AOB ) Influencing factors
CLC: X703
Type: Master's thesis
Year: 2010
Downloads: 144
Quote: 1
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Abstract


Nitrogen is one of the most restrictive elements of terrestrial ecosystems, plant photosynthesis and primary production process. The wetland sediment inorganic nitrogen content is usually maintained at a lower level, which often is the most important limiting nutrient. The wetland sediments Nitrogen nitrification is an important part of the nitrogen biogeochemical cycles, their study can reveal not only the wet nitrogen biogeochemical behavior and ecological significance, but also for exploring the wetland ecosystem productivity and nitrogen interface processes of great significance. In order to understand the nitrification in the Liaohe River Estuary reed wetland pollution purification function in the role and contribution in the estuary wetland nitrogen cycle, further Liaohe estuary wetland ecosystem restoration and management to provide a reference. In this paper, scene investigation training and laboratory simulation training method of combining the distribution characteristics of the Liaohe estuary wetland surface sediments of nitrifying bacteria and nitrification rate of ammonia-oxidizing bacteria (ammonia-Oxidizing bacteria, AOB) and nitrification rate environment the relationship between the factor and select several major influencing factors (temperature, pH, salinity, NH4-N concentration, organic matter and petroleum hydrocarbon content), design control experiments using single-factor analysis to analysis to verify. Using site simulation training pillar method to determine the net nitrification rate, laboratory liquid culture method for the determination of potential nitrification rate, MPN-Griess method for the determination of the number of AOB, correlation and regression analysis using SPSS 13.0 software analyzes the influencing factors with the relationship between nitrification. The results show that: (1) 2009 Liaohe mouth reed wetland surface sediments of the number of AOB in June between 0.54 × 104-5.69 × 104 · g-1 with an average of 2.21 × 104 g-1; 8 months between 1.90 × 104-7.90 × 104 · g-1, with an average to 3.61 × 104 g-1; 9 month between 0.12 × 104-0.36 × 104 · g-1, with an average of 0.21 × 104 · g-1. The sediment potential nitrification rate in June between 9.72-16.45mmol · m-2 · h-1, average 12.54mmol · m-2 · h-1; August in 14.66-24.62mmol · m-2 · h -1 18.71mmol · m-2 · h-1, with an average of 9 month between 8.22-12.37mmol · m-2 · h-1, with an average of 9.69mmol · m-2 · h-1 . Net nitrification rate in June (S1 station) 0.41 mmol · m-2 · h-1; 8 net nitrification rates ranging between 0.20-0.53mmol · m-2 · h-1, with an average of 0.35mmol · m-2 · h-1; 9 month (S1 station) 0.23mmol · m-2 · h-1. Potential nitrification rate was significantly higher than the net nitrification rate AOB number, net nitrification rate and potential nitrification rate performance of the August GT; June gt; 9 months, reed rhizosphere effect on nitrification role in promoting. (2) the statistical analysis by SPSS 13.0 software overlying water temperature, DO, NH4-N concentration and sediment pH, organic matter, TN, NH4-N content, indicating that the impact Liaohe mouth reed wetland surface sediment nitrification main environmental factors as well as the number of AOB (p lt; 0.05), NH4-N content of the overlying water, sediment pH and NH4-N content of nitrification, Liaohe Estuary Wetland nitrification impact of the key factors. (3) Select several major influencing factors (temperature, pH, NH4-N concentration, salinity, organic matter content and petroleum hydrocarbon content), the use of single-factor design control experiments to analyze the nitrification using linear regression analysis and Path analysis nitrification degree of influence: salinity gt; petroleum hydrocarbon content gt; NH4-N concentration gt; organic matter content gt; pH value gt; temperature; (4) nitrification nitrogen cycle in wetlands important process in Liaohe mouth reed wetland nitrogen cycle plays an important role, combined with the measured data can be estimated Liaohe reed wetland surface sediments day will of 1.02 × 105kgNH4-N converted to NO3 - N, equivalent to Liaohe River Basin NH4-N and NO3 - N into the sea flux of 44.2% and 10.9%, have a major impact on the Liaohe reed wetland nitrogen cycle.

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CLC: > Environmental science, safety science > Processing and comprehensive utilization of waste > General issues > Wastewater treatment and utilization
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