Articles | Volume 19, issue 9
https://doi.org/10.5194/bg-19-2397-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-19-2397-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
06 May 2022
Research article |
| 06 May 2022
| 06 May 2022
A nitrate budget of the Bohai Sea based on an isotope mass balance model
Shichao Tian
CORRESPONDING AUTHOR
Institute for Geology, Universität Hamburg, 20146 Hamburg,
Germany
Birgit Gaye
Institute for Geology, Universität Hamburg, 20146 Hamburg,
Germany
Jianhui Tang
Yantai Institute of Coastal Zone Research, Chinese Academy of
Sciences, Yantai, China
Yongming Luo
Yantai Institute of Coastal Zone Research, Chinese Academy of
Sciences, Yantai, China
Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
Wenguo Li
Institute of Oceanography, Universität Hamburg, 20146 Hamburg,
Germany
Niko Lahajnar
Institute for Geology, Universität Hamburg, 20146 Hamburg,
Germany
Kirstin Dähnke
Institute for Coastal Research, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Tina Sanders
Institute for Coastal Research, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Tianqi Xiong
Institute of Marine Science and Technology, Shandong University,
Qingdao, China
Weidong Zhai
Institute of Marine Science and Technology, Shandong University,
Qingdao, China
Kay-Christian Emeis
Institute for Geology, Universität Hamburg, 20146 Hamburg,
Germany
Institute for Coastal Research, Helmholtz-Zentrum Hereon, 21502 Geesthacht,
Germany
Related authors
No articles found.
Eugene Odion Oboh, Niko Lahajnar, Birgit Gaye, Avanti Shrikumar, and Tim Rixen
EGUsphere, https://doi.org/10.5194/egusphere-2025-4712, https://doi.org/10.5194/egusphere-2025-4712, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
We studied water mass distribution and oxygen consumption changes in low oxygen regions of the Indian Ocean and found slightly more oxygen present in these regions in 2016/2018 compared to 1995, contrary to the expected decline. This change is linked to a shift in ocean circulation that brought more oxygen-rich waters from the south to the north. Our results show that the development of these low oxygen regions is connected to the relationship between climate change and ocean circulation.
Anjaly Govindankutty Menon, Aaron L. Bieler, Hanna Firrincieli, Rachel Alcorn, Niko Lahajnar, Catherine V. Davis, Ralf Schiebel, Dirk Nürnberg, Gerhard Schmiedl, and Nicolaas Glock
Clim. Past, 21, 1853–1869, https://doi.org/10.5194/cp-21-1853-2025, https://doi.org/10.5194/cp-21-1853-2025, 2025
Short summary
Short summary
The pore density (number of pores per unit area) of unicellular eukaryotes is used to reconstruct past bottom-water nitrate at the Sea of Okhotsk, the Gulf of California, the Mexican Margin and the Gulf of Guayaquil. The reconstructed bottom-water nitrate at the Sea of Okhotsk, the Gulf of California and the Gulf of Guayaquil are influenced by the intermediate water masses, while the nitrate at the Mexican Margin is related to the deglacial NO3− variability in the Pacific Deep Water.
Gesa Schulz, Kirstin Dähnke, Tina Sanders, Jan Penopp, Hermann W. Bange, Rena Czeschel, and Birgit Gaye
Biogeosciences, 22, 5943–5959, https://doi.org/10.5194/bg-22-5943-2025, https://doi.org/10.5194/bg-22-5943-2025, 2025
Short summary
Short summary
Oxygen-minimum zones (OMZs) are low-oxygen ocean areas that deplete nitrogen, a key marine nutrient. Understanding nitrogen cycling in OMZs is crucial for the global nitrogen cycle. This study examined nitrogen cycling in the OMZ of the Bay of Bengal and the East Equatorial Indian Ocean, revealing limited mixing between both regions. Surface phytoplankton consumes nitrate, while deeper nitrification recycles nitrogen. In the BoB’s OMZ (100–300 m), nitrogen loss likely occurs via anammox.
Andreas Neumann, Justus E. E. van Beusekom, Alexander Bratek, Jana Friedrich, Jürgen Möbius, Tina Sanders, Hendrik Wolschke, and Kirstin Dähnke
EGUsphere, https://doi.org/10.5194/egusphere-2025-1803, https://doi.org/10.5194/egusphere-2025-1803, 2025
Short summary
Short summary
The North-Western shelf of the Black Sea is substantially influenced by the discharge of nutrients from River Danube. We have sampled the sediment there and measured particulate carbon and nitrogen to reconstruct the variability of nitrogen sources to the NW shelf. Our results demonstrate that the balance of riverine nitrogen input and marine nitrogen fixation is sensitive to climate changes. Nitrogen from human activities is detectable in NW shelf sediment since the 12th century.
Jan Maier, Nicole Burdanowitz, Gerhard Schmiedl, and Birgit Gaye
Clim. Past, 21, 279–297, https://doi.org/10.5194/cp-21-279-2025, https://doi.org/10.5194/cp-21-279-2025, 2025
Short summary
Short summary
We reconstruct sea surface temperatures (SSTs) of the past 43 kyr in the Gulf of Oman. We find SST variations of up to 7 °C with lower SSTs during Heinrich events (HEs), especially HE4, and higher SSTs during Dansgaard–Oeschger events. Our record shows no profound cooling during the Last Glacial Maximum but abrupt variations during the Holocene. We surmise that SST variations are influenced by the southwest (northeast) monsoon during warmer (colder) periods.
Bennet Juhls, Anne Morgenstern, Jens Hölemann, Antje Eulenburg, Birgit Heim, Frederieke Miesner, Hendrik Grotheer, Gesine Mollenhauer, Hanno Meyer, Ephraim Erkens, Felica Yara Gehde, Sofia Antonova, Sergey Chalov, Maria Tereshina, Oxana Erina, Evgeniya Fingert, Ekaterina Abramova, Tina Sanders, Liudmila Lebedeva, Nikolai Torgovkin, Georgii Maksimov, Vasily Povazhnyi, Rafael Gonçalves-Araujo, Urban Wünsch, Antonina Chetverova, Sophie Opfergelt, and Pier Paul Overduin
Earth Syst. Sci. Data, 17, 1–28, https://doi.org/10.5194/essd-17-1-2025, https://doi.org/10.5194/essd-17-1-2025, 2025
Short summary
Short summary
The Siberian Arctic is warming fast: permafrost is thawing, river chemistry is changing, and coastal ecosystems are affected. We aimed to understand changes in the Lena River, a major Arctic river flowing to the Arctic Ocean, by collecting 4.5 years of detailed water data, including temperature and carbon and nutrient contents. This dataset records current conditions and helps us to detect future changes. Explore it at https://doi.org/10.1594/PANGAEA.913197 and https://lena-monitoring.awi.de/.
Luisa Chiara Meiritz, Tim Rixen, Anja Karin van der Plas, Tarron Lamont, and Niko Lahajnar
Biogeosciences, 21, 5261–5276, https://doi.org/10.5194/bg-21-5261-2024, https://doi.org/10.5194/bg-21-5261-2024, 2024
Short summary
Short summary
Moored and drifting sediment trap experiments in the northern (nBUS) and southern (sBUS) Benguela Upwelling System showed that active carbon fluxes by vertically migrating zooplankton were about 3 times higher in the sBUS than in the nBUS. Despite these large variabilities, the mean passive particulate organic carbon (POC) fluxes were almost equal in the two subsystems. The more intense near-bottom oxygen minimum layer seems to lead to higher POC fluxes and accumulation rates in the nBUS.
Medhavi Pandey, Haimanti Biswas, Daniel Birgel, Nicole Burdanowitz, and Birgit Gaye
Biogeosciences, 21, 4681–4698, https://doi.org/10.5194/bg-21-4681-2024, https://doi.org/10.5194/bg-21-4681-2024, 2024
Short summary
Short summary
We analysed sea surface temperature (SST) proxy and plankton biomarkers in sediments that accumulate sinking material signatures from surface waters in the central Arabian Sea (21°–11° N, 64° E), a tropical basin impacted by monsoons. We saw a north–south SST gradient, and the biological proxies showed more organic matter from larger algae in the north. Smaller algae and zooplankton were more numerous in the south. These trends were related to ocean–atmospheric processes and oxygen availability.
Nicole Burdanowitz, Gerhard Schmiedl, Birgit Gaye, Philipp M. Munz, and Hartmut Schulz
Biogeosciences, 21, 1477–1499, https://doi.org/10.5194/bg-21-1477-2024, https://doi.org/10.5194/bg-21-1477-2024, 2024
Short summary
Short summary
We analyse benthic foraminifera, nitrogen isotopes and lipids in a sediment core from the Gulf of Oman to investigate how the oxygen minimum zone (OMZ) and bottom water (BW) oxygenation have reacted to climatic changes since 43 ka. The OMZ and BW deoxygenation was strong during the Holocene, but the OMZ was well ventilated during the LGM period. We found an unstable mode of oscillating oxygenation states, from moderately oxygenated in cold stadials to deoxygenated in warm interstadials in MIS 3.
Wenwen Ma, Rong Sun, Xiaoping Wang, Zheng Zong, Shizhen Zhao, Zeyu Sun, Chongguo Tian, Jianhui Tang, Song Cui, Jun Li, and Gan Zhang
Atmos. Chem. Phys., 24, 1509–1523, https://doi.org/10.5194/acp-24-1509-2024, https://doi.org/10.5194/acp-24-1509-2024, 2024
Short summary
Short summary
This is the first report of long-term atmospheric PAH monitoring around the Bohai Sea. The results showed that the concentrations of PAHs in the atmosphere around the Bohai Sea decreased from June 2014 to May 2019, especially the concentrations of highly toxic PAHs. This indicates that the contributions from PAH sources changed to a certain extent in different areas, and it also led to reductions in the related health risk and medical costs following pollution prevention and control.
Mona Norbisrath, Andreas Neumann, Kirstin Dähnke, Tina Sanders, Andreas Schöl, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 20, 4307–4321, https://doi.org/10.5194/bg-20-4307-2023, https://doi.org/10.5194/bg-20-4307-2023, 2023
Short summary
Short summary
Total alkalinity (TA) is the oceanic capacity to store CO2. Estuaries can be a TA source. Anaerobic metabolic pathways like denitrification (reduction of NO3− to N2) generate TA and are a major nitrogen (N) sink. Another important N sink is anammox that transforms NH4+ with NO2− into N2 without TA generation. By combining TA and N2 production, we identified a TA source, denitrification, occurring in the water column and suggest anammox as the dominant N2 producer in the bottom layer of the Ems.
Gesa Schulz, Tina Sanders, Yoana G. Voynova, Hermann W. Bange, and Kirstin Dähnke
Biogeosciences, 20, 3229–3247, https://doi.org/10.5194/bg-20-3229-2023, https://doi.org/10.5194/bg-20-3229-2023, 2023
Short summary
Short summary
Nitrous oxide (N2O) is an important greenhouse gas. However, N2O emissions from estuaries underlie significant uncertainties due to limited data availability and high spatiotemporal variability. We found the Elbe Estuary (Germany) to be a year-round source of N2O, with the highest emissions in winter along with high nitrogen loads. However, in spring and summer, N2O emissions did not decrease alongside lower nitrogen loads because organic matter fueled in situ N2O production along the estuary.
Maria-Elena Vorrath, Juliane Müller, Paola Cárdenas, Thomas Opel, Sebastian Mieruch, Oliver Esper, Lester Lembke-Jene, Johan Etourneau, Andrea Vieth-Hillebrand, Niko Lahajnar, Carina B. Lange, Amy Leventer, Dimitris Evangelinos, Carlota Escutia, and Gesine Mollenhauer
Clim. Past, 19, 1061–1079, https://doi.org/10.5194/cp-19-1061-2023, https://doi.org/10.5194/cp-19-1061-2023, 2023
Short summary
Short summary
Sea ice is important to stabilize the ice sheet in Antarctica. To understand how the global climate and sea ice were related in the past we looked at ancient molecules (IPSO25) from sea-ice algae and other species whose dead cells accumulated on the ocean floor over time. With chemical analyses we could reconstruct the history of sea ice and ocean temperatures of the past 14 000 years. We found out that sea ice became less as the ocean warmed, and more phytoplankton grew towards today's level.
Olga Ogneva, Gesine Mollenhauer, Bennet Juhls, Tina Sanders, Juri Palmtag, Matthias Fuchs, Hendrik Grotheer, Paul J. Mann, and Jens Strauss
Biogeosciences, 20, 1423–1441, https://doi.org/10.5194/bg-20-1423-2023, https://doi.org/10.5194/bg-20-1423-2023, 2023
Short summary
Short summary
Arctic warming accelerates permafrost thaw and release of terrestrial organic matter (OM) via rivers to the Arctic Ocean. We compared particulate organic carbon (POC), total suspended matter, and C isotopes (δ13C and Δ14C of POC) in the Lena delta and Lena River along a ~1600 km transect. We show that the Lena delta, as an interface between the Lena River and the Arctic Ocean, plays a crucial role in determining the qualitative and quantitative composition of OM discharged into the Arctic Ocean.
Jiao Tang, Jun Li, Shizhen Zhao, Guangcai Zhong, Yangzhi Mo, Hongxing Jiang, Bin Jiang, Yingjun Chen, Jianhui Tang, Chongguo Tian, Zheng Zong, Jabir Hussain Syed, Jianzhong Song, and Gan Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2023-403, https://doi.org/10.5194/egusphere-2023-403, 2023
Preprint archived
Short summary
Short summary
This study provides a comprehensive molecular identification of atmospheric common fluorescent components and deciphers their related formation pathways. The fluorescent components varied in molecular composition, and a dominant oxidation pathway for the formation of humic-like fluorescent components was suggested, notwithstanding their different precursor types. Our findings are expected to be helpful to further studies using the EEM-PARAFAC as a tool to study atmospheric BrC.
Kirstin Dähnke, Tina Sanders, Yoana Voynova, and Scott D. Wankel
Biogeosciences, 19, 5879–5891, https://doi.org/10.5194/bg-19-5879-2022, https://doi.org/10.5194/bg-19-5879-2022, 2022
Short summary
Short summary
Nitrogen is an important macronutrient that fuels algal production in rivers and coastal regions. We investigated the production and removal of nitrogen-bearing compounds in the freshwater section of the tidal Elbe Estuary and found that particles in the water column are key for the production and removal of water column nitrate. Using a stable isotope approach, we pinpointed regions where additional removal of nitrate or input from sediments plays an important role in estuarine biogeochemistry.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
Short summary
Short summary
Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Matthias Fuchs, Juri Palmtag, Bennet Juhls, Pier Paul Overduin, Guido Grosse, Ahmed Abdelwahab, Michael Bedington, Tina Sanders, Olga Ogneva, Irina V. Fedorova, Nikita S. Zimov, Paul J. Mann, and Jens Strauss
Earth Syst. Sci. Data, 14, 2279–2301, https://doi.org/10.5194/essd-14-2279-2022, https://doi.org/10.5194/essd-14-2279-2022, 2022
Short summary
Short summary
We created digital, high-resolution bathymetry data sets for the Lena Delta and Kolyma Gulf regions in northeastern Siberia. Based on nautical charts, we digitized depth points and isobath lines, which serve as an input for a 50 m bathymetry model. The benefit of this data set is the accurate mapping of near-shore areas as well as the offshore continuation of the main deep river channels. This will improve the estimation of river outflow and the nutrient flux output into the coastal zone.
Charlotte Haugk, Loeka L. Jongejans, Kai Mangelsdorf, Matthias Fuchs, Olga Ogneva, Juri Palmtag, Gesine Mollenhauer, Paul J. Mann, P. Paul Overduin, Guido Grosse, Tina Sanders, Robyn E. Tuerena, Lutz Schirrmeister, Sebastian Wetterich, Alexander Kizyakov, Cornelia Karger, and Jens Strauss
Biogeosciences, 19, 2079–2094, https://doi.org/10.5194/bg-19-2079-2022, https://doi.org/10.5194/bg-19-2079-2022, 2022
Short summary
Short summary
Buried animal and plant remains (carbon) from the last ice age were freeze-locked in permafrost. At an extremely fast eroding permafrost cliff in the Lena Delta (Siberia), we found this formerly frozen carbon well preserved. Our results show that ongoing degradation releases substantial amounts of this carbon, making it available for future carbon emissions. This mobilisation at the studied cliff and also similarly eroding sites bear the potential to affect rivers and oceans negatively.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
Short summary
Short summary
Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
Birgit Gaye, Niko Lahajnar, Natalie Harms, Sophie Anna Luise Paul, Tim Rixen, and Kay-Christian Emeis
Biogeosciences, 19, 807–830, https://doi.org/10.5194/bg-19-807-2022, https://doi.org/10.5194/bg-19-807-2022, 2022
Short summary
Short summary
Amino acids were analyzed in a large number of samples of particulate and dissolved organic matter from coastal regions and the open ocean. A statistical analysis produced two new biogeochemical indicators. An indicator of sinking particle and sediment degradation (SDI) traces the degradation of organic matter from the surface waters into the sediments. A second indicator shows the residence time of suspended matter in the ocean (RTI).
Nicole Burdanowitz, Tim Rixen, Birgit Gaye, and Kay-Christian Emeis
Clim. Past, 17, 1735–1749, https://doi.org/10.5194/cp-17-1735-2021, https://doi.org/10.5194/cp-17-1735-2021, 2021
Short summary
Short summary
To study the interaction of the westerlies and Indian summer monsoon (ISM) during the Holocene, we used paleoenvironmental reconstructions using a sediment core from the northeast Arabian Sea. We found a climatic transition period between 4.6 and 3 ka BP during which the ISM shifted southwards and the influence of Westerlies became prominent. Our data indicate a stronger influence of agriculture activities and enhanced soil erosion, adding to Bond event impact after this transition period.
Jiao Tang, Jiaqi Wang, Guangcai Zhong, Hongxing Jiang, Yangzhi Mo, Bolong Zhang, Xiaofei Geng, Yingjun Chen, Jianhui Tang, Congguo Tian, Surat Bualert, Jun Li, and Gan Zhang
Atmos. Chem. Phys., 21, 11337–11352, https://doi.org/10.5194/acp-21-11337-2021, https://doi.org/10.5194/acp-21-11337-2021, 2021
Short summary
Short summary
This article provides a combined EEM–PARAFAC and statistical analysis method to explore how excitation–emission matrix (EEM) chromophores influence BrC light absorption in soluble organic matter. The application enables us to deduce that BrC absorption is mainly dependent on longer-emission-wavelength chromophores largely associated with biomass burning emissions. This method promotes the application of EEM spectroscopy and helps us understand the light absorption of BrC in the atmosphere.
Tim Rixen, Greg Cowie, Birgit Gaye, Joaquim Goes, Helga do Rosário Gomes, Raleigh R. Hood, Zouhair Lachkar, Henrike Schmidt, Joachim Segschneider, and Arvind Singh
Biogeosciences, 17, 6051–6080, https://doi.org/10.5194/bg-17-6051-2020, https://doi.org/10.5194/bg-17-6051-2020, 2020
Short summary
Short summary
The northern Indian Ocean hosts an extensive oxygen minimum zone (OMZ), which intensified due to human-induced global changes. This includes the occurrence of anoxic events on the Indian shelf and affects benthic ecosystems and the pelagic ecosystem structure in the Arabian Sea. Consequences for biogeochemical cycles are unknown, which, in addition to the poor representation of mesoscale features, reduces the reliability of predictions of the future OMZ development in the northern Indian Ocean.
Cited articles
Altabet, M. A.: Isotopic tracers of the marine nitrogen cycle: present and
past, in: Marine organic matter: biomarkers, isotopes and DNA, Springer,
251–293, https://doi.org/10.1007/698_2_008, 2006.
Backhaus, J. O.: A three-dimensional model for the simulation of shelf sea
dynamics, Dtsch. Hydrogr. Zetischrift, 38, 165–187, https://doi.org/10.1007/BF02328975, 1985.
Benson, B. B. and Krause Jr., D.: The concentration and isotopic
fractionation of oxygen dissolved in freshwater and seawater in equilibrium
with the atmosphere 1, Limnol. Oceanogr., 29, 620–632, https://doi.org/10.4319/lo.1984.29.3.0620, 1984.
Casciotti, K., Trull, T., Glover, D., and Davies, D.: Constraints on
nitrogen cycling at the subtropical North Pacific Station ALOHA from
isotopic measurements of nitrate and particulate nitrogen, Deep-Sea Res.
Pt. II, 55, 1661–1672, 2008.
Casciotti, K. L., Sigman, D. M., Hastings, M. G., Böhlke, J., and
Hilkert, A.: Measurement of the oxygen isotopic composition of nitrate in
seawater and freshwater using the denitrifier method, Anal. Chem., 74,
4905–4912, https://doi.org/10.1021/ac020113w, 2002.
Casciotti, K. L., Böhlke, J. K., McIlvin, M. R., Mroczkowski, S. J., and
Hannon, J. E.: Oxygen isotopes in nitrite: Analysis, calibration, and
equilibration, Anal. Chem., 79, 2427–2436, https://doi.org/10.1021/ac061598h, 2007.
Casciotti, K. L., Trull, T. W., Glover, D. M., and Davies, D.: Constraints
on nitrogen cycling at the subtropical North Pacific Station ALOHA from
isotopic measurements of nitrate and particulate nitrogen, Deep-Sea Res.
Pt. II, 55, 1661–1672, https://doi.org/10.1016/j.dsr2.2008.04.017, 2008.
Chang, Y., Zhang, Y.-L., Li, J., Tian, C., Song, L., Zhai, X., Zhang, W., Huang, T., Lin, Y.-C., Zhu, C., Fang, Y., Lehmann, M. F., and Chen, J.: Isotopic constraints on the atmospheric sources and formation of nitrogenous species in clouds influenced by biomass burning, Atmos. Chem. Phys., 19, 12221–12234, https://doi.org/10.5194/acp-19-12221-2019, 2019.
Chen, C.-T. A.: Chemical and physical fronts in the Bohai, Yellow and East
China seas, J. Mar. Syst., 78, 394–410, https://doi.org/10.1016/j.jmarsys.2008.11.016, 2009.
Chen, F., Chen, J., Jia, G., Jin, H., Xu, J., Yang, Z., Zhuang, Y., Liu, X.,
and Zhang, H.: Nitrate ä 15N and ä 18O evidence for active
biological transformation in the Changjiang Estuary and the adjacent East
China Sea, Acta Oceanol. Sin., 32, 11–17, https://doi.org/10.1007/s13131-013-0294-4,
2013.
Chen, F., Lao, Q., Zhang, S., Bian, P., Jin, G., Zhu, Q., and Chen, C.:
Nitrate sources and biogeochemical processes identified using nitrogen and
oxygen isotopes on the eastern coast of Hainan Island, Cont. Shelf Res., 207,
104209, https://doi.org/10.1016/j.csr.2020.104209, 2020.
Chen, J., Taniguchi, M., Liu, G., Miyaoka, K., Onodera, S.-I., Tokunaga, T.,
and Fukushima, Y.: Nitrate pollution of groundwater in the Yellow River
delta, China, Hydrogeol. J., 15, 1605–1614, https://doi.org/10.1007/s10040-007-0196-7, 2007.
Copernicus Climate Change Service: ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate, Copernicus Climate Change Service Climate Data Store (CDS), https://cds.climate.copernicus.eu/cdsapp#!/home (last access: 30 April 2022), 2017.
Devol, A. H.: Denitrification, Anammox, and N2 Production in Marine
Sediments, Ann. Rev. Mar. Sci., 7, 403–423,
https://doi.org/10.1146/annurev-marine-010213-135040, 2015.
DiFiore, P. J., Sigman, D. M., Trull, T. W., Lourey, M. J., Karsh, K., Cane,
G., and Ho, R.: Nitrogen isotope constraints on subantarctic
biogeochemistry, J. Geophys. Res.-Oean., 111, C08016, https://doi.org/10.1029/2005JC003216, 2006.
DiFiore, P. J., Sigman, D. M., and Dunbar, R. B.: Upper ocean nitrogen
fluxes in the Polar Antarctic Zone: Constraints from the nitrogen and oxygen
isotopes of nitrate, Geochem. Geophy. Geosy., 10, Q11016, https://doi.org/10.1029/2009GC002468, 2009.
Egbert, G. D., and Erofeeva, S. Y.: Efficient inverse modeling of barotropic
ocean tides, J. Atmos. Ocean. Tech., 19, 183–204, https://doi.org/10.1175/1520-0426(2002)019<0183:EIMOBO>2.0.CO;2, 2002.
Emeis, K. C., Mara, P., Schlarbaum, T., Möbius, J., Dähnke, K.,
Struck, U., Mihalopoulos, N., and Krom, M.: External N inputs and internal N
cycling traced by isotope ratios of nitrate, dissolved reduced nitrogen, and
particulate nitrogen in the eastern Mediterranean Sea, J. Geophys.
Res.-Biogeo., 115, G04041, https://doi.org/10.1029/2009JG001214, 2010.
Fan, M.-Y., Zhang, Y.-L., Lin, Y.-C., Chang, Y.-H., Cao, F., Zhang, W.-Q.,
Hu, Y.-B., Bao, M.-Y., Liu, X.-Y., Zhai, X.-Y., Lin, X., Zhao, Z.-Y., and
Song, W.-H.: Isotope-based source apportionment of nitrogen-containing
aerosols: A case study in an industrial city in China, Atmos. Environ., 212,
96–105, https://doi.org/10.1016/j.atmosenv.2019.05.020, 2019.
Fowler, D., Coyle, M., Skiba, U., Sutton, M. A., Cape, J. N., Reis, S., Sheppard, L. J., Jenkins, A., Grizzetti, B., Galloway, J. N., Vitousek, P., Leach, A., Bouwman, A. F., Butterbach-Bahl, K., Dentener, F., Stevenson, D., Amann, M., and Voss, M.: The global nitrogen cycle in the twenty-first century, Philos. T. R. Soc. B, 368, 20130164, https://doi.org/10.1098/rstb.2013.0164, 2013.
Glibert, P. M., Wilkerson, F. P., Dugdale, R. C., Raven, J. A., Dupont, C.
L., Leavitt, P. R., Parker, A. E., Burkholder, J. M., and Kana, T. M.:
Pluses and minuses of ammonium and nitrate uptake and assimilation by
phytoplankton and implications for productivity and community composition,
with emphasis on nitrogen-enriched conditions,
Limnol. Oceanogr., 61, 165–197, https://doi.org/10.1002/lno.10203, 2016.
Granger, J. and Sigman, D. M.: Removal of nitrite with sulfamic acid for
nitrate N and O isotope analysis with the denitrifier method, Rapid Commun.
Mass Spectrom., 23, 3753–3762, https://doi.org/10.1002/rcm.4307, 2009.
Granger, J., Sigman, D. M., Rohde, M., Maldonado, M., and Tortell, P.: N and
O isotope effects during nitrate assimilation by unicellular prokaryotic and
eukaryotic plankton cultures, Geochim. Cosmochim. Ac., 74, 1030–1040,
https://doi.org/10.1016/j.gca.2009.10.044, 2010.
Grasshoff, K., Kremling, K., and Ehrhardt, M.: Methods of seawater analysis,
John Wiley & Sons, Cambridge University Press, https://doi.org/10.1017/S0025315400028216, 2009.
Gu, B., Ju, X., Chang, J., Ge, Y., and Vitousek, P. M.: Integrated reactive
nitrogen budgets and future trends in China, P. Natl. Acad. Sci. USA,
112, 8792, https://doi.org/10.1073/pnas.1510211112, 2015.
Hainbucher, D., Hao, W., Pohlmann, T., Sündermann, J., and Feng, S.:
Variability of the Bohai Sea circulation based on model calculations, J.
Mar. Syst., 44, 153–174, https://doi.org/10.1016/j.jmarsys.2003.09.008, 2004.
Huang, D., Su, J., and Backhaus, J. O.: Modelling the seasonal thermal
stratification and baroclinic circulation in the Bohai Sea, Cont. Shelf
Res., 19, 1485–1505, https://doi.org/10.1016/S0278-4343(99)00026-6, 1999.
IFA: Short-Term Fertilizer Outlook 2019–2020, Versailles, 8, IFA Strategic Forum, https://api.ifastat.org/reports/download/12796 (last access: 30 April 2022), 2019.
Jia, B., and Chen, X. E.: Application of an ice-ocean coupled model to Bohai
Sea ice simulation, J. Oceanol. Limnol., 39, 1–13,
https://doi.org/10.1007/s00343-020-9168-8, 2021.
Kang, D.-J., Chung, C. S., Kim, S. H., Hong, G. H., and Kim, K.-R.: Oxygen
isotope characteristics of seawaters in the Yellow Sea, La Mer, 32, 279–284,
1994.
Kérouel, R. and Aminot, A.: Fluorometric determination of ammonia in
sea and estuarine waters by direct segmented flow analysis, Mar. Chem., 57,
265–275, https://doi.org/10.1016/S0304-4203(97)00040-6, 1997.
Kim, H., Park, G.-H., Lee, S.-E., Kim, Y.-i., Lee, K., Kim, Y.-H., and Kim,
T.-W.: Stable isotope ratio of atmospheric and seawater nitrate in the East
Sea in the northwestern Pacific ocean, Mar. Pollut. Bull., 149, 110610,
https://doi.org/10.1016/j.marpolbul.2019.110610, 2019.
Lehmann, M. F., Sigman, D. M., and Berelson, W. M.: Coupling the 15N
Lellouche, J. M., Legalloudec, O., Regnier, C., Levier, B., Greiner, E., and Drevillon, M.: QUALITY INFORMATION DOCUMENT For Global Sea Physical Analysis and Forecasting Product, GLOBAL_ANALYSIS_FORECAST_PHY_001_024, EU Copernicus Marine Service, https://catalogue.marine.copernicus.eu/documents/QUID/CMEMS-GLO-QUID-001-024.pdf (last access: 30 April 2022), 2019.
Li, Y., Wolanski, E., and Zhang, H.: What processes control the net currents
through shallow straits? A review with application to the Bohai Strait,
China, Estuar. Coast. Shelf Sci., 158, 1–11, https://doi.org/10.1016/j.ecss.2015.03.013, 2015.
Li, Y., Yan, W., Wang, F., Lv, S., Li, Q., and Yu, Q.: Nitrogen pollution
and sources in an aquatic system at an agricultural coastal area of Eastern
China based on a dual-isotope approach, Environ. Sci. Pollut.
Res., 26, 23807–23823, https://doi.org/10.1007/s11356-019-05665-2, 2019.
Li, Z., Walters, W. W., Hastings, M. G., Zhang, Y., Song, L., Liu, D.,
Zhang, W., Pan, Y., Fu, P., and Fang, Y.: Nitrate Isotopic Composition in
Precipitation at a Chinese Megacity: Seasonal Variations, Atmospheric
Processes, and Implications for Sources, Earth Space Sci., 6, 2200–2213, https://doi.org/10.1029/2019EA000759, 2019.
Liu, J., Du, J., and Yi, L.: Ra Tracer-Based Study of Submarine Groundwater
Discharge and Associated Nutrient Fluxes into the Bohai Sea, China: A Highly
Human-Affected Marginal Sea, J. Geophys. Res.-Oean., 122, 8646–8660,
https://doi.org/10.1002/2017JC013095, 2017.
Liu, S., Hong, G.-H., Zhang, J., Ye, X., and Jiang, X.: Nutrient budgets for
large Chinese estuaries, Biogeosciences, 6, 2245–2263, https://doi.org/10.5194/bg-6-2245-2009, 2009.
Liu, S. M., Zhang, J., and Jiang, W. S.: Pore water nutrient regeneration in
shallow coastal Bohai Sea, China, J. Oceanogr., 59, 377–385, https://doi.org/10.1023/A:1025576212927, 2003.
Liu, S. M., Li, L. W., and Zhang, Z.: Inventory of nutrients in the Bohai,
Cont. Shelf Res., 31, 1790–1797, https://doi.org/10.1016/j.csr.2011.08.004, 2011.
Liu, S. M., Altabet, M. A., Zhao, L., Larkum, J., Song, G. D., Zhang, G. L.,
Jin, H., and Han, L. J.: Tracing Nitrogen Biogeochemistry During the
Beginning of a Spring Phytoplankton Bloom in the Yellow Sea Using Coupled
Nitrate Nitrogen and Oxygen Isotope Ratios, J. Geophys. Res.-Biogeo., 122,
2490–2508, https://doi.org/10.1002/2016jg003752, 2017.
Liu, S. M., Ning, X., Dong, S., Song, G., Wang, L., Altabet, M. A., Zhu, Z.,
Wu, Y., Ren, J. L., and Liu, C. G.: Source Versus Recycling Influences on
the Isotopic Composition of Nitrate and Nitrite in the East China Sea, J.
Geophys. Res.-Ocean., 125, e2020JC016061, https://doi.org/10.1029/2020JC016061, 2020.
Lu, C. and Tian, H.: Global nitrogen and phosphorus fertilizer use for agriculture production in the past half century: shifted hot spots and nutrient imbalance, Earth Syst. Sci. Data, 9, 181–192, https://doi.org/10.5194/essd-9-181-2017, 2017.
Luo, X. and Jiao, J. J.: Submarine groundwater discharge and nutrient
loadings in Tolo Harbor, Hong Kong using multiple geotracer-based models,
and their implications of red tide outbreaks, Water Res., 102, 11–31,
https://doi.org/10.1016/j.watres.2016.06.017, 2016.
Ma, S., Xin, F., Cui, Y., and Qiao, X.: Assessment of Main Pollution Matter
Volume into the Sea from Yellow River and Xiaoqing Rive, Prog. Fish.
Sci., 25, 47–51, https://doi.org/10.3969/j.issn.1000-7075.2004.05.009,
2004 (in Chines).
Möbius, J.: Isotope fractionation during nitrogen remineralization
(ammonification): Implications for nitrogen isotope biogeochemistry,
Geochim. Cosmochim. Ac., 105, 422–432, https://doi.org/10.1016/j.gca.2012.11.048, 2013.
Montoya, J. P., Carpenter, E. J., and Capone, D. G.: Nitrogen fixation and
nitrogen isotope abundances in zooplankton of the oligotrophic North
Atlantic, Limnol. Oceanogr., 47, 1617–1628, https://doi.org/10.4319/lo.2002.47.6.1617, 2002.
Müller Schmied, H., Eisner, S., Franz, D., Wattenbach, M., Portmann, F. T., Flörke, M., and Döll, P.: Sensitivity of simulated global-scale freshwater fluxes and storages to input data, hydrological model structure, human water use and calibration, Hydrol. Earth Syst. Sci., 18, 3511–3538, https://doi.org/10.5194/hess-18-3511-2014, 2014.
Murphy, J. and Riley, J. P.: A modified single solution method for the
determination of phosphate in natural waters, Anal. Chim. Acta, 27, 31–36,
1962.
MWR, China: China Water Resources Bulletin, China Water & Power Press, Beijing, http://mwr.gov.cn/sj/tjgb/zghlnsgb/ (last access: 30 April 2022), 2015–2018.
MWR, China: China River Sediment Bulletin 2018, China Water & Power Press, http://mwr.gov.cn/sj/tjgb/zghlnsgb/201906/t20190618_1342326.html (last access: 30 April 2022), 2019.
Ning, X., Lin, C., Su, J., Liu, C., Hao, Q., Le, F., and Tang, Q.: Long-term
environmental changes and the responses of the ecosystems in the Bohai Sea
during 1960–1996, Deep-Sea Res. Pt. II, 57, 1079–1091, https://doi.org/10.1016/j.dsr2.2010.02.010, 2010.
Pätsch, J., Serna, A., Dähnke, K., Schlarbaum, T., Johannsen, A.,
and Emeis, K.-C.: Nitrogen cycling in the German Bight (SE North
Sea)—Clues from modelling stable nitrogen isotopes, Cont. Shelf Res., 30,
203–213, https://doi.org/10.1016/j.csr.2009.11.003, 2010.
Peterson, R. N., Burnett, W. C., Taniguchi, M., Chen, J., Santos, I. R., and
Ishitobi, T.: Radon and radium isotope assessment of submarine groundwater
discharge in the Yellow River delta, China, J. Geophys. Res.-Oean., 113, C09021,
https://doi.org/10.1029/2008JC004776, 2008.
Schlitzer, R.: Ocean Data View, https://odv.awi.de (last access: 30 April 2022), 2021.
Serna, A., Pätsch, J., Dähnke, K., Wiesner, M. G., Hass, H. C.,
Zeiler, M., Hebbeln, D., and Emeis, K.-C.: History of anthropogenic nitrogen
input to the German Bight/SE North Sea as reflected by nitrogen isotopes in
surface sediments, sediment cores and hindcast models, Cont. Shelf Res., 30,
1626–1638, https://doi.org/10.1016/j.csr.2010.06.010, 2010.
Sigman, D. M. and Fripiat, F.: Nitrogen Isotopes in the Ocean, in:
Encyclopedia of Ocean Sciences (Third Edition), edited by: Cochran, J. K.,
Bokuniewicz, H. J., and Yager, P. L., Academic Press, Oxford, 263–278, https://doi.org/10.1016/B978-0-12-409548-9.11605-7, 2019.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M.,
and Böhlke, J.: A bacterial method for the nitrogen isotopic analysis of
nitrate in seawater and freshwater, Anal. Chem., 73, 4145–4153, https://doi.org/10.1021/ac010088e, 2001.
Sigman, D. M., Granger, J., DiFiore, P. J., Lehmann, M. M., Ho, R., Cane,
G., and van Geen, A.: Coupled nitrogen and oxygen isotope measurements of
nitrate along the eastern North Pacific margin, Global Biogeochem. Cy.,
19, GB4022, https://doi.org/10.1029/2005GB002458, 2005.
Sigman, D. M., DiFiore, P. J., Hain, M. P., Deutsch, C., Wang, Y., Karl, D.
M., Knapp, A. N., Lehmann, M. F., and Pantoja, S.: The dual isotopes of deep
nitrate as a constraint on the cycle and budget of oceanic fixed nitrogen,
Deep-Sea Res. Pt. I, 56, 1419–1439, https://doi.org/10.1016/j.dsr.2009.04.007, 2009.
Smith, S. V., Swaney, D. P., Talaue-Mcmanus, L., Bartley, J. D., Sandhei, P.
T., McLAUGHLIN, C. J., Dupra, V. C., Crossland, C. J., Buddemeier, R. W.,
and Maxwell, B. A.: Humans, hydrology, and the distribution of inorganic
nutrient loading to the ocean, Bioscience, 53, 235–245, https://doi.org/10.1641/0006-3568(2003)053[0235:HHATDO]2.0.CO;2, 2003.
Soares, M.: Biological denitrification of groundwater, Water, Air, Soil
Pollut., 123, 183–193, 2000.
Song, W., Liu, X.-Y., Wang, Y.-L., Tong, Y.-D., Bai, Z.-P., and Liu, C.-Q.:
Nitrogen isotope differences between atmospheric nitrate and corresponding
nitrogen oxides: A new constraint using oxygen isotopes, Sci. Total
Environ., 701, 134515, https://doi.org/10.1016/j.scitotenv.2019.134515, 2020.
Su, J.: A review of circulation dynamics of the coastal oceans near China, Acta Oceanol. Sin., 23, 1–16,
https://doi.org/10.3321/j.issn:0253-4193.2001.04.001, 2001 (in Chinese).
Sugimoto, R., Kasai, A., Miyajima, T., and Fujita, K.: Transport of oceanic
nitrate from the continental shelf to the coastal basin in relation to the
path of the Kuroshio, Cont. Shelf Res., 29, 1678–1688, https://doi.org/10.1016/j.csr.2009.05.013, 2009.
Tan, S. and Shi, G.: Satellite-derived primary productivity and its spatial
and temporal variability in the China seas, J. Geogr.
Sci., 16, 447–457, https://doi.org/10.1007/s11442-006-0408-4, 2006.
Umezawa, Y., Yamaguchi, A., Ishizaka, J., Hasegawa, T., Yoshimizu, C., Tayasu, I., Yoshimura, H., Morii, Y., Aoshima, T., and Yamawaki, N.: Seasonal shifts in the contributions of the Changjiang River and the Kuroshio Current to nitrate dynamics in the continental shelf of the northern East China Sea based on a nitrate dual isotopic composition approach, Biogeosciences, 11, 1297–1317, https://doi.org/10.5194/bg-11-1297-2014, 2014.
Wang, J., Yu, Z., Wei, Q., and Yao, Q.: Long-term
nutrient variations in the Bohai Sea over the past 40 years, J. Geophys.
Res.-Oean., 124, 703–722, https://doi.org/10.1029/2018JC014765,
2019.
Wang, W., Yu, Z., Song, X., Wu, Z., Yuan, Y., Zhou, P., and Cao, X.: The
effect of Kuroshio Current on nitrate dynamics in the southern East China
Sea revealed by nitrate isotopic composition, J. Geophys. Res.-Oean., 121,
7073–7087, https://doi.org/10.1002/2016JC011882, 2016.
Wang, W., Yu, Z., Song, X., Wu, Z., Yuan, Y., Zhou, P., and Cao, X.:
Characteristics of the δ15N
Wang, X., Li, H., Jiao, J. J., Barry, D. A., Li, L., Luo, X., Wang, C., Wan,
L., Wang, X., and Jiang, X.: Submarine fresh groundwater discharge into
Laizhou Bay comparable to the Yellow River flux, Sci. Rep.-UK, 5, 8814,
https://doi.org/10.1038/srep08814, 2015.
Wankel, S. D., Kendall, C., Francis, C. A., and Paytan, A.: Nitrogen sources
and cycling in the San Francisco Bay Estuary: A nitrate dual isotopic
composition approach, Limnol. Oceanogr., 51, 1654–1664, https://doi.org/10.4319/lo.2006.51.4.1654, 2006.
Wankel, S. D., Kendall, C., Pennington, J. T., Chavez, F. P., and Paytan,
A.: Nitrification in the euphotic zone as evidenced by nitrate dual isotopic
composition: Observations from Monterey Bay, California, Global Biogeochem.
Cy., 21, GB2009, https://doi.org/10.1029/2006GB002723, 2007.
Wei, H., Zhao, L., and Feng, S.: Annual cycle of phytoplankton biomass and
primary production in the Bohai Sea simulated by a three-dimensional
ecosystem model, Acta Oceanol. Sin., 25, 66–72, 2003 (in Chinese).
Wong, G. T.: Removal of nitrite interference in the Winkler determination of
dissolved oxygen in seawater, Mar. Chem., 130, 28–32, https://doi.org/10.1016/j.marchem.2011.11.003, 2012.
Wu, S.: Oxygen isotope compositions of seawaters in the Huanghai (Yellow)
Sea and the Bohai Sea, Sci. China Ser. B, 34, 327–337,
http://www.cnki.com.cn/Article/CJFDTotal-JBXG199103008.htm (last access: 30 April 2022), 1991.
Wu, Z., Yu, Z., Song, X., Wang, W., Zhou, P., Cao, X., and Yuan, Y.: Key
nitrogen biogeochemical processes in the South Yellow Sea revealed by dual
stable isotopes of nitrate, Estuar. Coast. Shelf Sci., 225, 106222,
https://doi.org/10.1016/j.ecss.2019.05.004, 2019.
Wurl, O.: Practical guidelines for the analysis of seawater, CRC press, ISBN 1420073079,
2009.
Xin, M., Wang, B., Xie, L., Sun, X., Wei, Q., Liang, S., and Chen, K.:
Long-term changes in nutrient regimes and their ecological effects in the
Bohai Sea, China, Mar. Pollut. Bull., 146, 562–573, https://doi.org/10.1016/j.marpolbul.2019.07.011, 2019.
Xu, S., Song, J., Li, X., Yuan, H., Li, N., Duan, L., and Sun, P.: Changes
in nitrogen and phosphorus and their effects on phytoplankton in the Bohai
Sea, China J. Oceanol. Limnol., 28, 945–952, https://doi.org/10.1007/s00343-010-0005-3,
2010.
Yang, Z., Chen, J., Li, H., Jin, H., Gao, S., Ji, Z., Zhu, Y., Ran, L.,
Zhang, J., and Liao, Y.: Sources of nitrate in Xiangshan Bay (China), as
identified using nitrogen and oxygen isotopes, Estuar. Coast. Shelf Sci.,
207, 109–118, https://doi.org/10.1016/j.ecss.2018.02.019, 2018.
Yellow River Conservancy Commission of MWR (China): Yellow River Sediment
Bulletin 2018, in: Yellow River Conservancy Commission of MWR,
China, Zhengzhou, 35 pp., http://www.yrcc.gov.cn/nishagonggao/2018/index.html#p=1 (last access: 30 April 2022), 2019 (in Chinese).
Yu, H., Yu, Z., Song, X., Cao, X., Yuan, Y., and Lu, G.: Seasonal variations
in the nitrogen isotopic composition of dissolved nitrate in the Changjiang
River estuary, China, Estuar. Coast. Shelf Sci., 155, 148–155, https://doi.org/10.1016/j.ecss.2015.01.017, 2015.
Yu, J., Zhang, W., Tan, Y., Zong, Z., Hao, Q., Tian, C., Zhang, H., Li, J.,
Fang, Y., and Zhang, G.: Dual-isotope-based source apportionment of nitrate
in 30 rivers draining into the Bohai Sea, north China, Environ. Pollut.,
283, 117112, https://doi.org/10.1016/j.envpol.2021.117112,
2021.
Yu, Q., Lou, A., Zhang, X., and Li, N.: Numerical Analysis on the Impact of
Main River Runoff on the Plain Distribution in the Low-Salinity Area at
North Liaodong Bay, Trans. Oceanol. Limnol., 2,
88–96, https://doi.org/10.13984/j.cnki.cn37-1141.2018.02.012, 2018 (in Chinese).
Yue, F.-J., Li, S.-L., Liu, C.-Q., Zhao, Z.-Q., and Hu, J.: Using dual
isotopes to evaluate sources and transformation of nitrogen in the Liao
River, northeast China, Appl. Geochem., 36, 1–9, https://doi.org/10.1016/j.apgeochem.2013.06.009, 2013.
Zhang, G., Zhang, J., and Liu, S.: Characterization of nutrients in the
atmospheric wet and dry deposition observed at the two monitoring sites over
Yellow Sea and East China Sea, J. Atmos. Chem., 57, 41–57,
https://doi.org/10.1007/s10874-007-9060-3, 2007.
Zhang, J., Yu, Z., Raabe, T., Liu, S., Starke, A., Zou, L., Gao, H., and
Brockmann, U.: Dynamics of inorganic nutrient species in the Bohai
seawaters, J. Mar. Syst., 44, 189–212, https://doi.org/10.1016/j.jmarsys.2003.09.010, 2004.
Zhang, L., Song, L., Zhang, L., Shao, H., Chen, X., and Yan, K.: Seasonal
dynamics in nitrous oxide emissions under different types of vegetation in
saline-alkaline soils of the Yellow River Delta, China and implications for
eco-restoring coastal wetland, Ecol. Eng., 61, 82–89, https://doi.org/10.1016/j.ecoleng.2013.09.065, 2013.
Zhang, X., Zhang, Q., Yang, A., Hou, L., Zheng, Y., Zhai, W., and Gong, J.:
Incorporation of Microbial Functional Traits in Biogeochemistry Models
Provides Better Estimations of Benthic Denitrification and Anammox Rates in
Coastal Oceans, J. Geophys. Res.-Biogeo., 123, 3331–3352, https://doi.org/10.1029/2018JG004682, 2018.
Zhang, Y., Liu, X., Fangmeier, A., Goulding, K., and Zhang, F.: Nitrogen
inputs and isotopes in precipitation in the North China Plain, Atmos.
Environ., 42, 1436–1448, https://doi.org/10.1016/j.atmosenv.2007.11.002, 2008.
Zhang, Z., Zheng, N., Zhang, D., Xiao, H., Cao, Y., and Xiao, H.: Rayleigh
based concept to track NOx emission sources in urban areas of China, Sci.
Total Environ., 704, 135362, https://doi.org/10.1016/j.scitotenv.2019.135362, 2019.
Zhao, L., Wei, H., and Feng S.: Annual Cycle and Budgets of Nutrients in the Bohai Sea, Chinese J. Environ. Sci., 1, 29–37, https://en.cnki.com.cn/Article_en/CJFDTotal-QDHB200201006.htm, 2002
Zhao, Y., Zhang, L., Chen, Y., Liu, X., Xu, W., Pan, Y., and Duan, L.:
Atmospheric nitrogen deposition to China: A model analysis on nitrogen
budget and critical load exceedance, Atmos. Environ., 153, 32–40, https://doi.org/10.1016/j.atmosenv.2017.01.018, 2017.
Zong, Z., Wang, X., Tian, C., Chen, Y., Fang, Y., Zhang, F., Li, C., Sun,
J., Li, J., and Zhang, G.: First Assessment of NOx Sources at a Regional
Background Site in North China Using Isotopic Analysis Linked with Modeling,
Environ. Sci. Technol., 51, 5923–5931, https://doi.org/10.1021/acs.est.6b06316, 2017.
Short summary
We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in...
Altmetrics
Final-revised paper
Preprint