于2010~2011年间分4个季节, 对大亚湾海域尿素浓度及浮游生物的脲酶活性开展调查研究, 结合相关理化环境及生物因子, 分析大亚湾海域尿素的可利用性及其对浮游植物群落演替的影响。结果表明, 海区尿素浓度变化范围为0.81~8.54μmol N·L^-1, 夏季尿素含量最高, 达4.32 ± 1.65μmol N·L^-1; 冬季含量最低, 为1.57 ± 0.49μmol N·L^-1。夏、秋季节有很多站位尿素水平甚至超过溶解无机氮(dissolved inorganic nitrogen, DIN)含量1~3倍, 表明尿素是大亚湾海域浮游植物生长不可忽略的重要氮源。较高水平的尿素主要分布在养殖区和靠近陆地的近岸海域。浮游生物脲酶活性在秋季最高, 平均达61.0 ± 33.6nmol N·L^-1·h^-1, 冬、春季脲酶活性常低于检出限。在秋季, 浮游生物脲酶活性与甲藻密度密切相关。脲酶已被证明是大洋中浮游植物水解尿素的最主要途径, 因此尿素可能在一定程度上影响大亚湾甲藻等浮游植物的生长。

Cruises were carried out to survey urea concentration and urease activity together with other environmental parameters in the Daya Bay. The bioavailability of urea for succession in the phytoplankton community was analyzed based on these cruise data. The results showed that the average concentration of urea varied from 0.81 to 8.54 μmol N·L^-1 in the four seasons. The urea concentration was the highest in summer, up to 4.32±1.65μmol N·L^-1, and the lowest in winter, up to 1.57±0.49 μmol N·L^-1. There were many stations where urea concentrations were 1-3 times higher than dissolved inorganic nitrogen (DIN) in summer and autumn, which suggested that urea as one important nitrogen source should not be ignored in the growth and productivity of phytoplankton in the Daya Bay. Higher levels of urea were distributed in the aquaculture area and the nearshore waters where sewage drains were located. Plankton urease activities were the highest in autumn, up to 61.0 ± 33.6 nmol N ·L^-1·h^-1; however, in winter and spring the urease activities were often below the detection limit. Dinoflagellates densities were closely related to urease activities in autumn. Urease activity has been shown to be the most important way in the hydrolysis of urea by of phytoplankton in the oceans, so urea may affect the growth of dinoflagellates and other phytoplankton in the Daya Bay.