Distinguishing the Isotopic Signals of Nitrate Assimilation and Denitrification Along the GEOTRACES GP15 Pacific Meridional Transect
文献类型：期刊论文
| 作者 | Marconi, Dario4; Sigman, Daniel M.4; Casciotti, Karen L.3; Lawrence, Rian M.3; Wang, Wentao2; Oleynik, Sergey4; Martinez-Garcia, Alfredo1 |
| 刊名 | JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
 |
| 出版日期 | 2025-06-01 |
| 卷号 | 130期号:6页码:20 |
| 关键词 | nitrate isotopes nitrate assimilation denitrification |
| ISSN号 | 2169-9275 |
| DOI | 10.1029/2024JC022084 |
| 通讯作者 | Marconi, Dario(dmarconi@princeton.edu) |
| 英文摘要 | The biogeochemical processes shaping the fluxes of nitrogen (N) in the tropical to subarctic Pacific are illuminated by nitrate isotope ratios (delta 15N and delta 18O) along the GEOTRACES GP15 section. In the equatorial and tropical Pacific, nitrate delta 15N and delta 18O are 2-4 parts per thousand higher in the thermocline than in deeper waters. This widespread elevation is driven by both nitrate assimilation in Southern Ocean surface waters and denitrification in the eastern tropical Pacific. In addition to this, a poleward increase in the delta 15N of surface nitrate from the Equator to 10 degrees S is generated by the progressive consumption of nitrate upwelled at the Equator and transported southward. This process leads to increases in the delta 15N of phytoplankton biomass and a strong meridional nitrate isotopic gradient in the thermocline due to regeneration of sinking N. North of the Equator, an analogous gradient is barely detectable due to weaker northward flow and a compressed spatial scale for nitrate drawdown. By contrast, between 5 degrees N and 40 degrees N, the nitrate isotope gradients are dominated by the processes driving the oceanic fixed N budget: denitrification and N2 fixation. High-delta 15N and -delta 18O nitrate in the tropics is advected from the oxygen deficient zone where denitrification occurs, whereas in the adjacent subtropics, low-delta 15N thermocline nitrate suggests a response by N2 fixation that is not observed in the south. The asymmetry of the north and south tropical Pacific gradients in thermocline nitrate isotopes has implications for efforts to reconstruct the N cycle in the past. |
| WOS关键词 | NITROGEN-FIXATION ; OXYGEN ISOTOPES ; SOUTHERN-OCEAN ; NITRITE ; FRACTIONATION ; DELTA-N-15 ; NORTHEAST ; N-2 ; DISTRIBUTIONS ; CIRCULATION |
| 资助项目 | Daniel M. Sigman[OCE1736652] ; Daniel M. Sigman[OCE1851430] ; Daniel M. Sigman[OCE1657944] ; US NSF ; OCE |
| WOS研究方向 | Oceanography |
| 语种 | 英语 |
| WOS记录号 | WOS:001503233300001 |
| 出版者 | AMER GEOPHYSICAL UNION |
| 源URL | [http://ir.qdio.ac.cn/handle/337002/202259]  |
| 专题 | 中国科学院海洋研究所 |
| 通讯作者 | Marconi, Dario |
| 作者单位 | 1.Max Planck Inst Chem, Mainz, Germany 2.Chinese Acad Sci, Inst Oceanol, Qingdao, Peoples R China 3.Stanford Univ, Dept Earth Syst Sci, Stanford, CA USA 4.Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA |
| 推荐引用方式 GB/T 7714 | Marconi, Dario,Sigman, Daniel M.,Casciotti, Karen L.,et al. Distinguishing the Isotopic Signals of Nitrate Assimilation and Denitrification Along the GEOTRACES GP15 Pacific Meridional Transect[J]. JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,2025,130(6):20. |
| APA | Marconi, Dario.,Sigman, Daniel M..,Casciotti, Karen L..,Lawrence, Rian M..,Wang, Wentao.,...&Martinez-Garcia, Alfredo.(2025).Distinguishing the Isotopic Signals of Nitrate Assimilation and Denitrification Along the GEOTRACES GP15 Pacific Meridional Transect.JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS,130(6),20. |
| MLA | Marconi, Dario,et al."Distinguishing the Isotopic Signals of Nitrate Assimilation and Denitrification Along the GEOTRACES GP15 Pacific Meridional Transect".JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS 130.6(2025):20. |
入库方式： OAI收割
来源：海洋研究所
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