Perturbation-free measurement of in situ di-nitrogen emissions from denitrification in nitrate-rich aquatic ecosystems

Shuping Qin, Timothy Clough, Jiafa Luo, Nicole Wrage-Mönnig, Oene Oenema, Yuming Zhang, Chunsheng Hu*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

4 Citations (Scopus)

Abstract

Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) has greatly contributed to increased food production. However, enriching the biosphere with Nr has also caused a series of negative effects on global ecosystems, especially aquatic ecosystems. The main pathway converting Nr back into the atmospheric N2 pool is the last step in the denitrification process. Despite several attempts, there is still a need for perturbation-free methods for measuring in situ N2 fluxes from denitrification in aquatic ecosystems at the field scale. Such a method is needed to comprehensively quantify the N2 fluxes from aquatic ecosystems. Here we observed linear relationships between the δ15N-N2O signatures and the logarithmically transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the perturbation-free N2 flux from denitrification in nitrate-rich aquatic ecosystems can be inferred from these linear relationships. Our method allowed the determination of field-scale in situ N2 fluxes from nitrate-rich aquatic ecosystems both with and without overlaying water. The perturbation-free in situ N2 fluxes observed by the new method were almost one order of magnitude higher than those by the sediment core method. The ability of aquatic ecosystems to remove Nr may previously have been severely underestimated.

Original languageEnglish
Pages (from-to)94-101
JournalWater Research
Volume109
DOIs
Publication statusPublished - 2017

Keywords

  • Denitrification
  • Isotopic fractionation
  • NO reduction
  • Nitrogen loss
  • Reactive nitrogen

Fingerprint Dive into the research topics of 'Perturbation-free measurement of in situ di-nitrogen emissions from denitrification in nitrate-rich aquatic ecosystems'. Together they form a unique fingerprint.

  • Cite this