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| Rates of nitrification and nitrate assimilation in the Changjiang River estuary and adjacent waters based on the nitrogen isotope dilution method | |
Wang, Wentao1 ; Yu, Zhiming1; Wu, Zaixing1; Song, Shuqun1; Song, Xiuxian1; Yuan, Yongquan1; Cao, Xihua1
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| 2018-07-01 | |
| Source Publication | CONTINENTAL SHELF RESEARCH
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| ISSN | 0278-4343 |
| Volume | 163Pages:35-43 |
| Subtype | Article |
| Abstract | Being supplied from both terrestrial inputs and internal regeneration, nitrate is usually in excess in the Changjiang River estuary (CRE) and adjacent waters (CREAW). As significant reactions in the nitrogen cycle, nitrate assimilation and nitrification rates were calculated by field incubation experiments following the isotope dilution method during June and November 2014. Besides this, distribution of other field parameters in the CREAW were also investigated. The results showed that the nitrate assimilation rates were higher in nearshore areas and lower in offshore areas. The nitrate assimilation rates were also higher during June, at 0.3-11.9 mu mol L-1 d(-1), whereas the rates were 0-3.2 mu mol L-1 d(-1) in November. The highest rate was observed in the surface water of the estuary, where the chlorophyll-a (chl-a) concentration reached 11.02 mu g L-1. In addition, the phytoplankton community structure affected the nitrate assimilation rates, and dinoflagellates presented weaker nitrate assimilation abilities than those of diatoms. By contrast, the nitrification rates were higher in nearshore areas in June but higher in offshore areas in November. The nitrification rates were 0-4.1 mu mol L-1 d(-1) and 0-3.6 mu mol L-1 d(-1) in June and November, respectively. At most sites, the nitrification rates were positively correlated with the ammonium concentrations and were higher in November, which might be attributable to the higher temperature. Moreover, a theoretical calculation was used to study the regional nitrate flux throughout the vertical water column. The results showed that a gradual supplement from nitrification might replenish the nitrate consumed by assimilation far from the CRE. The overall result was that terrestrial input remained the primary source of estuarine nitrate; however, the role of internal nitrate regeneration, which would be effective for primary production in the CREAW, should also be highlighted as a source of nitrate, especially in offshore areas. |
| Keyword | Changjiang River estuary Nitrogen cycle Isotope dilution Assimilation Nitrification |
| Subject Area | Oceanography |
| DOI | 10.1016/j.csr.2018.04.014 |
| Indexed By | SCIE |
| Language | 英语 |
| WOS Research Area | Oceanography |
| WOS ID | WOS:000436219700004 |
| Publisher | PERGAMON-ELSEVIER SCIENCE LTD |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.qdio.ac.cn/handle/337002/157561 |
| Collection | 海洋生态与环境科学重点实验室 |
| Affiliation | 1.Chinese Acad Sci, Inst Oceanol, CAS Key Lab Marine Ecol & Environm Sci, Qingdao, Peoples R China 2.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Ecol & Environm Sci, Qingdao, Peoples R China |
| First Author Affilication | Institute of Oceanology, Chinese Academy of Sciences |
| Recommended Citation GB/T 7714 | Wang, Wentao,Yu, Zhiming,Wu, Zaixing,et al. Rates of nitrification and nitrate assimilation in the Changjiang River estuary and adjacent waters based on the nitrogen isotope dilution method[J]. CONTINENTAL SHELF RESEARCH,2018,163:35-43. |
| APA | Wang, Wentao.,Yu, Zhiming.,Wu, Zaixing.,Song, Shuqun.,Song, Xiuxian.,...&Cao, Xihua.(2018).Rates of nitrification and nitrate assimilation in the Changjiang River estuary and adjacent waters based on the nitrogen isotope dilution method.CONTINENTAL SHELF RESEARCH,163,35-43. |
| MLA | Wang, Wentao,et al."Rates of nitrification and nitrate assimilation in the Changjiang River estuary and adjacent waters based on the nitrogen isotope dilution method".CONTINENTAL SHELF RESEARCH 163(2018):35-43. |
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| Rates of nitrificati（1959KB） | 期刊论文 | 出版稿 | 开放获取 | CC BY-NC-SA | View | |
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