| 摘要: |
| 20世纪90年代，科学家们对海洋沉积物中氮的行为等进行了较深入的研究(宋金明，1997； Hammond et al.，1996；Jordan et al.，1998)。如氮的早期成岩过程、氮的去营养化作用、氮在沉积物-海水界面的转移过程及交换通量。近年来实施的全球性重大合作计划，如 JGOFS、GLOBEC、SOLAS等进一步加强了对海洋中的氮循环的研究(Collier，1991；Smith et al.，1996)。随着研究的深入，沉积物中氮循环的控制机制、氮循环与其他生源要素循环的关系及其生物地球化学功能等方面的研究已经成为目前研究的焦点。以往的研究工作大多集中于从沉积物间隙水这一角度研究沉积物中的氮循环，而对沉积物本身研究较少，主要是由于研究手段、方法的缺乏(甄别沉积物中氮的各种赋存形态极为困难)。而通过对沉积物初步的研究已证明(马红波等，2001)，沉积物固体颗粒本身的特征，如颗粒大小及氮在其中的赋存形态对较长时间尺度上的氮循环过程具有重要影响。本文作者在研究沉积物氮形态基础上，对渤海沉积物氮的生物地球化学功能进行了探讨，以期对深入研究生源要素的循环过程提供基础依据。 |
| 关键词: 沉积物 氮循环 生物地球化学功能 |
| DOI： |
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| 基金项目:中国科学院海洋研究所调查研究报告第4538号。国家杰出青年科学基金(49925614)与中国科学院知识创新工程重大项目KZCX1-SW-01-08资助。 |
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| BIOGEOCHEMICAL FUNCTIONS OF NITROGEN IN BOHAI SEA SEDIMENTS |
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SONG Jinming1, MA Hongbo1,2, LÜ Xiaoxia1,2, YUAN Huamao1,2
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1.MEES, Institute of Oceanology, The Chinese Academy of Sciences;2.Graduate School of the Chinese Academy of Sciences
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| Abstract: |
| Nitrogen forms in marine sediment play an important role in its biogeochemical cycling. Up to now, most studies focus on total nitrogen (TN), organic nitrogen (ON) and inorganic nitrogen and could not yield integrated information on nitrogen cycling because different nitrogen forms contributing to their cyclings are different. In this work, nitrogen of Bohai Sea sediment in natural size was divided into transferable and untransferable parts by sequential extraction method for the first time. Estimation of transferable nitrogen and its function in sediment-water exchange showed that the contributions of different nitrogen forms in nitrogen recycling vary on time scale. Estimation indicated that IEF-N and OSF-N exist mostly at the surface of the sediment grain, and act as dominant participator in recycling, IMOF-N and CF-N are mainly present inside the sediment grain and contribute little to recycling. The nitrogen cycling budget for Bohai Sea shows that the contribution of pelagic recycling (74.4%) to primary productivity is much more than benthic recycling (26.1%).
Analysis of the correlation between sediment nitrogen and primary product ion showed that it is very close. IEF-N acts as a "buffer pool" for nitrogen nutrient which can enhance primary productivity. Benthos bioturbation is conducive to enhancement of mineralization, which results in high NH4+ and NO3- distribution in deep sediments. Contribution of nitrogen forms in recycling varies on time scale. The absolute contribution of each state is consistent with its content in sediment, which has the sequence OSF-N (84.6%) > IEF-N (13.0) > IMOF-N (1.4%) CF-N (1.0%). Untransferable nitrogen account for 69.15% of TN, among which 49% is due to inclusion in sediment grain interior. |
| Key words: marine sediment biogeochemical cycling |
