钦州湾海域不同季节尿素与浮游植物脲酶活性分布特征

The distribution characteristic of urea concentration and urease activity of phytoplankton in Qinzhou bay

  • 摘要: 2015年至2016年间,对钦州湾海域开展了四个航次调查研究,结合其它理化环境因子,对该海域尿素含量和浮游植物脲酶活性季节分布特征及影响因素以及尿素的来源和生物可利用性进行了初步探讨。结果表明,钦州湾表层水体中尿素分布呈现明显的由内湾向外湾递减的趋势,含量范围为0.24~5.14 μmol N/L,平均值夏季>春季>冬季>秋季,其中夏季尿素平均值为3.30 ±1.14 μmol N/L。浮游植物脲酶活性为0.15~2.60 μmol N/(L·h),冬季浮游植物脲酶活性最高,平均为0.91 ±0.55 μmol N/(L·h),其次是秋季和夏季,春季脲酶活性最低。不同季节尿素含量均≥1.00 μmol N/L,占溶解态有机氮(DON)的1.2%~63.0%,平均值为(15.6 ±14.2)%,表明尿素是钦州湾海域的重要氮源。钦州湾尿素含量和分布主要决定于陆源输入,尿素是DON的重要组成部分,故钦州湾DON具有较高的生物可利用性,为该海域浮游植物生长提供重要的氮源。

     

    Abstract: To study distributing characteristic and influencing factors of urea concentration and urease activities in different seasons in Qinzhou bay, four field cruises were carried out in in 2015~2016, base on the data the source and bioavailability of urea for phytoplankton were discussed together with other environmental parameters.Results showed that urea distribution in surface waters of Qinzhou bay presented obvious decreasing from the inner bay to the outer bay, the concentration of urea ranged from 0.24 to 5.14 μmol N/L, arranged in order of its average is summer > spring > winter > autumn, its average was 3.30 ±1.14 μmol N/L in the summer.The urease activitie of plankton ranged from 0.15~2.60 μmol N/(L·h) with the maximum average(0.91 ±0.55 μmol N/(L·h)) in the winter and the minimum in the spring, while summer and autumn were in the middle.The concentration of urea in all seasons was equal or greater than 1.00 μmol N/Land accounted for 1.2%~63.0% of dissolved organic nitrogen (DON), with a mean of (15.6 ±14.2)%, which suggested that urea was an important nitrogen source in Qinzhou bay.In conclusion, the distribution of urea in Qinzhou bay mainly depends on the river input, and urea constituted a significant component of DON, so DON may have high biological availability for the phytoplankton growth as an important source of nitrogen.

     

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