摘要:根据2013年7月（夏季），11月（秋季）和2014年5月（春季）渤海中部氮、磷、硅营养盐库各赋存形态数据以及温度、盐度等水文数据，分析海域不同季节各营养盐库以及相互间转化规律。结果表明：调查海域受陆源输入、吸收转化、扰动混合以及分解释放等因素影响，各营养盐库含量及其组分迁移转化呈现明显的季节特征，春夏高生产力季节为无机态向有机态和颗粒态转化期，秋季为有机态和颗粒态溶解分解释放期。夏季氮磷营养盐库含量分别为（37.43±10.09）μmol/L和（0.73±0.19）μmol/L，且以溶解有机态为主要赋存形态。秋季各营养盐库以及无机态组分含量受扰动以及分解释放影响均明显增加，而溶解有机态和颗粒态组分降低，其中颗粒氮（PN，particulate nitrogen）含量为（1.78±1.05）μmol/L，降幅66%；溶解有机磷（DOP，dissolved organic phosphorus）含量为（0.13±0.06）μmol/L，降幅66%；而溶解无机磷（DIP，dissolved inorganic phosphorus）为（0.54±0.20）μmol/L，升高10.8倍。春季各营养盐库组分变化明显，其中溶解无机氮（DIN，dissolved inorganic nitrogen）、DIP和活性硅酸盐（SiO₃，reactive silicate）受浮游植物吸收转化影响，含量较秋季分别降幅45%、89%和85%，DON受秋冬季分解影响，含量降低36%。而PN和DOP增加明显，分别增高27%和1.6倍。调查海域各赋存形态营养盐比值表明，无机态营养盐比值均远离Redfield比值，对海域内硅藻的优势种地位产生影响。而各有机态以及颗粒态组分比值显示相比较氮，DOP、颗粒态磷（PP，particulate phosphorus）和硅在秋冬季低生产力季节更易受到扰动和分解释放影响，对于缓解海域内磷硅限制状况具有重要作用。



Abstract:Based on data of nitrogen, phosphorus and silicon nutrient pools and hydrological parameters collected in the center of the Bohai Sea during July 2013, November 2013 and May 2014 cruise, we studied the nutrient pool distributions and the nutrient speciation transformations. The results showed that nutrient pools had a strongly seasonal variation characteristic affected by terrigenous input, phytoplankton uptake, transformation, turbulent mixing and release from organic matter decomposition. During high productivity seasons in spring and summer, nutrients showed a transformation trend from inorganic compositions to organic and particulate compositions, while the dissolved organic and particulate phase nutrient compositions decomposed and transformed into inorganic phase in autumn. In summer, the nitrogen and phosphorous nutrients concentrations were (37.43±10.09) μmol/L and (0.73±0.19) μmol/L, respectively, with dissolved organic compositions dominate. In autumn, the concentrations of nutrients and inorganic components increased significantly, and the dissolved organic and particulate components decreased due to the disturbance and organic matter decomposition release effects. The concentrations of the particulate nitrogen (PN) and dissolved organic phosphorus (DOP) were (1.78±1.05) μmol/L and (0.13±0.06) μmol/L, respectively, and both reduced by 66% compared with summer cruise, while dissolved inorganic phosphorus (DIP) increased 10.8 times to (0.54±0.20) μmol/L. In spring, the nutrient compositions changed significantly. Dissolved inorganic nitrogen (DIN), DIP and reactive silicate (SiO₃) reduced by 45%, 89% and 85%, respectively, because of phytoplankton absorption, transformation and particulate matters sinking. DON reduced by 36% that influenced by decomposition during autumn and winter, while PN and DOP increased significantly by 27% and 160% than those in autumn, respectively. The nutrient ratios in different nutrient forms showed that the inorganic nutrient phases were far away from the Redfield ratio which had an important impact on the dominant status of diatom species. The nutrient ratios of dissolved organic and particulate nutrients showed DOP, particulate phosphorus (PP) and silicon were more easily impacted by organic matter decomposition and disturbance compared with nitrogen species during the autumn and winter low productivity seasons, which plays an important role in alleviating the phosphorus and silicon limitation in the Bohai Sea, China.





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