南海北部真光层亚硝酸盐最大值形成机制

The nitrite maximum depth in the euphotic layer of the northern South China Sea was selected as object of the study to explore its response and feedback to monsoon-driven dynamics.PCR-DGGE and other molecular biology techniques were employed to identify the diversity of nitrifying bacteria in euphotic layer.To determine nitrification rates, on-deck incubation was carried out to using an inhibitor technique, with the addition of allyithiourea (ATU) and sodium chlorate (NaClO3), respectively. At the same time, high performance liquid chromatography (HPLC) was employed to identify phytoplankton pigment which may exhibit the horizontal、vertical and seasonal variations.During the incubation, nitrite concentrations and in vivo chlorophyll fluorescence (as a measure of phytoplankton biomass) were monitored in the experimental flasks. Nitrification and nitrogen-nutrient metabolism of phytoplankton may play different role on forming primary nitrite maximum in euphotic layer in northern South China Sea,and couple with South China Sea monsoon.The results can reveal the key driven step and their associated ecological effects of marine nitrogen cycle of the euphotic zone in northern South China Sea. The information would be very useful to South China Sea agencies to carry out scientific plans for resource use based on biological production, and helpful in presenting important and key parameter about marine nitrogen cycle.

本项目以南海北部真光层亚硝酸盐为研究对象，研究并阐明亚硝酸盐最大值深度变化对南海季风的响应与反馈。运用PCR-DGGE等分子生物学技术摸清南海北部真光层硝化细菌的基因多样性，采用ATU(烯丙基硫脲)及氯酸钠（NaClO3)抑制技术现场测定硝化速率；同时运用高效液相色谱分析该区域浮游植物色素组成、空间分布和季节差异，现场测定浮游植物的氮营养代谢。探明硝化作用和浮游植物代谢对南海北部真光层亚硝酸盐最大值形成的贡献以及他们对南海季风的响应与耦合。揭示南海北部真光层氮循环的关键控制环节及其相关的生态效应。为我国南海生物生产的可持续发展提供理论依据，以及对全球海洋氮循环提供区域性的关键参数。

本项目以南海北部真光层亚硝酸盐为研究对象，研究并阐明亚硝酸盐最大值深度变化对南海季风的响应与反馈。运用PCR-DGGE 等分子生物学技术摸清南海北部真光层硝化细菌的基因多样性，同时运用高效液相色谱分析该区域浮游植物色素组成、空间分布和季节差异，现场测定浮游植物的氮营养代谢,西沙海域亚硝酸盐最大值形成硝化作用贡献23%；同时西沙海域水质主要是受自然变化影响。在湛江外海上升流真光层，微微型浮游植物主要是聚球藻，而原绿球藻则在非上升流区被发现。探明硝化作用和浮游植物代谢对南海北部真光层亚硝酸盐最大值形成的贡献以及他们对南海季风的响应与耦合。揭示南海北部真光层氮循环的关键控制环节及其相关的生态效应。发表SCI论文10篇，获得广州市科技进步一等奖1项（第五完成人）。