| 摘要: |
| 2011 年1～4 月, 分3 个航次对海南岛北部海口湾和南部陵水新村湾的尿素浓度和浮游生物脲酶活性开展调查研究, 结合相关理化环境因子, 比较分析海南岛南北部近岸海湾冬、春季尿素的可利用性及对浮游植物群落的影响。结果表明, 冬季(1～2 月), 北部海口湾尿素浓度范围(以N 计, 以下同)为0.93～4.13 μmol/L, 显著高于南部陵水新村湾0.38～2.05 μmol/L。春季, 海南岛南北部尿素浓度均有所升高, 平均占总溶解态氮源的含量由冬季的5%～7%增加到24%～30%, 变化显著, 表明尿素是海南岛近岸海湾不可忽视的氮源。海南岛南北部海湾冬季大部分浮游生物样品脲酶活性低于检出限。春季, 海口湾平均脲酶活性为44 nmol/(L·h)±23 nmol/(L·h), 呈现近岸入海口水体高于离岸的特征; 南部海湾平均脲酶活性升高到21 nmol/(L·h)±10 nmol/(L·h), 新村湾养殖区水体的脲酶活性高于陵水湾。水温和浮游植物细胞丰度是影响海南岛脲酶活性冬、春季变化的重要因素。冬季, 海口湾浮游植物细胞丰度显著低于陵水新村湾; 春季, 海口湾浮游植物细胞丰度增长到5.09×106个/L±7.45×106个/L, 冬、春季变化显著。海南岛南北部硅藻和甲藻细胞丰度冬、春季的变化均与硝酸盐和DIP 负相关, 而与脲酶活性和水温正相关, 尿素在不同程度上影响南北部细胞丰度的变化。 |
| 关键词: 尿素 脲酶活性 浮游植物 海南岛 |
| DOI：10.11759/hykx20130628001 |
| 分类号: |
| 基金项目:国家重点基础研究发展计划项目(2010CB428702); 国家自然科学基金项目(41176087; 41276153), 中央高校基本科研业务费专项资金资助项目(21611205) |
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| Comparative study on urea bioavailability by plankton in the southern and northern coastal waters of Hainan Island |
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| Abstract: |
| Field cruises were carried out on the southern and northern coastal waters of Hainan Island to survey the variation of urea concentrations and urease activities together with other environmental parameters during January to April, 2011. Results showed that the urea concentrations in the northern Haikou Bay (from 0.93 μmol/L to 4.13 μmol/L) were significantly higher than those in the southern Lingshui-Xincun Bay during the winter. During the April, the urea concentrations increased significantly to 24%～30% of total dissolved nitrogen, which showed that urea was as one important nitrogen source in the coastal waters of Hainan Island. The urease activities of most plankton samples in the winter were below the detection limit. In the spring, the urease activities of Haikou Bay and Lingshui-Xincun Bay increased significantly to 44 nmol/(L·h)±23 nmol/(L·h) and 21 nmol/(L·h)±10 nmol/(L·h) respectively. The urea concentrations and the urease activities in the nearshore waters where sewage draining and the aquaculture area located were higher than in the other waters. The urease activities during the winter and spring were mostly affected by water temperatures and cell abundance of phytoplankton. Cell abundances of Haikou Bay were significantly lower than Lingshui-Xincun Bay during the winter. In April, cell abundances of Haikou Bay increased significantly to 5.09 cells/L±7.45×106 cells/L. Cell abundances of diatom and dinoflagellates in the Hainan Island waters during the winter and spring were negative correlated with nitrate and DIP concentrations, while positive correlated with urease activities and water temperatures. The urea concentrations affected the variation of cell abundances at different degrees. Increasing water temperature, urease activities and urea concentrations were propitious to the growth of phytoplankton in the Hainan Island during the spring. |
| Key words: urea urease activity phytoplankton Hainan Island |
