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The Study on the Forms of Inorganic Nitrogen and Its Relationship with Denitrification Rate in the Northwest of the Yellow Sea

Author: YuJiangHua
Tutor: BaiJie
School: Ocean University of China
Course: Environmental Science
Keywords: Northwest of the Yellow Sea Can be extracted inorganic nitrogen Denitrification rate Denitrifying bacteria
CLC: X703
Type: Master's thesis
Year: 2008
Downloads: 52
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Abstract

With the economic and social development, human high-intensity activity makes estuaries, offshore areas of N input has increased annually, the Eutrophication become an increasingly serious problem facing the world today, the frequent occurrence of red tide phenomenon, caused by the marine ecological environment serious threat. Therefore, the study of the marine ecosystem nitrogen biogeochemical behavior become one of the priorities in the field of oceanographic research, study the form of nitrogen in marine sediments and sea water - sediment interface denitrification, in-depth study of the marine nitrogen loop has an important role. This article research was supported by the National Key Basic Research and Development Program (973 Program) (2006CB400602), Marine comprehensive survey of 908 project (908-01-ST02), the support of the Shandong Provincial Environmental Protection Foundation of China (2004040-1). Form of inorganic nitrogen in the sediment of the Yellow Sea waters northwest, the application classification leaching method, the distribution of inorganic nitrogen in the waters of sediments geochemical characteristics; improved acetylene inhibition assay (AIT) that sea area - sediment interface and denitrification in three seasons, the simultaneous determination of the number of denitrifying bacteria in the sediments, and their mutual relations. The results show that the extractable inorganic nitrogen content in the surface sediments of the Yellow Sea northwest and Distribution Characteristics: summer IEF-N, CF-N and IMOF-N can be extracted inorganic nitrogen content percentages were 92.25%, 1.90% and 5.84%; spring corresponding proportion of 86.62%, 2.09% and 11.37%, respectively; autumn corresponding ratio of 91.12%, 2.04% and 6.85%, respectively; Xia Chunqiu three seasons, IEF-N are extractable inorganic nitrogen Absolute Advantage state, the percentage content of more than 85%, followed by IMOF-N, the content thereof is higher than the CF-N times, significantly lower than the IEF-N content, the lowest content is CF-N in the extraction inorganic nitrogen percentage content of only about 2%. Acetylene inhibition method Xia Chunqiu three quarters of the Yellow Sea waters northwest of sea water - sediment interface denitrification rates were measured, and results show that the Xia Chunqiu three seasons denitrification rate 3.2 to 7.5,0.26 to 2.65 and 1.21 to 4.12 μmol/m2 · h, showing a significant seasonal variation, summer is the most denitrification season, followed by autumn, spring lowest; using the MPN method determined by the number of denitrifying bacteria of the different seasons in the sediments of the study area, The results showed that relatively large differences in the number of denitrifying bacteria season summer between 1.18 to 6.18 × 106ind / g, between 0.72 to 4.50 × 105ind / g in the spring, fall between 1.78 ~ 8.12 × 105ind / g. Denitrification rate, the number of denitrifying bacteria with different forms can be extracted findings show that the relationship between inorganic nitrogen, the Xia and summer denitrification rate and IEF-NO3-has a significant positive correlation, the correlation coefficient was 0.947 ( P lt; 0.01) and 0.888 (P lt; 0.05), spring anti-nitrification rate and CF-NH4 was a significant positive correlation, correlation coefficient of 0.887 (P lt; 0.05), with the rest of the form of inorganic nitrogen no significant correlation; spring the number of denitrifying bacteria with IEF-NO3-significant with a positive correlation (r = 0.893, P lt; 0.05), no significant correlation with the rest of the form of inorganic nitrogen; relationship between denitrification rates and denitrifying bacteria, spring and fall quarter of 0.759 and 0.750 (P lt; 0.05), no significant correlation in the summer. This study enrich the nitrogen biogeochemical cycles of China's offshore areas theoretical system.

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