Water residence time controls seasonal nitrous oxide budget in a semi-enclosed bay: Insights from an improvement estimation method

Mar Pollut Bull. 2024 Sep:206:116701. doi: 10.1016/j.marpolbul.2024.116701. Epub 2024 Jul 10.

Abstract

This study developed an estimation method for the N2O budget using 15N stable isotope labeling techniques, a dual-layer model and a box model, which was used to elucidate the underlying dynamics of N2O accumulation in Zhanjiang Bay. The results showed that although the net input of N2O during the rainy season was 2.36 times higher than that during the dry season, the overall N2O concentration was only 66.6 % of that during the dry season due to the extended water residence time in the dry season. Our findings highlighted that water residence time was the key factor for the N2O emission, and a longer water residence time was unfavorable for the efflux of N2O through hydrodynamic processes and was more conducive to the production and accumulation of N2O within the bay. This research enhanced our comprehension of N2O dynamics and provided crucial insights for refining nitrogen management strategies and mitigation efforts.

Keywords: (15)N isotope; N(2)O budget; Water retention time; Zhanjiang Bay.

MeSH terms

  • Bays*
  • China
  • Environmental Monitoring*
  • Nitrous Oxide* / analysis
  • Seasons*
  • Seawater / chemistry
  • Water Pollutants, Chemical / analysis

Substances

  • Nitrous Oxide
  • Water Pollutants, Chemical