Anthropogenic input of excess nutrients stimulates massive nitrous oxide (NO) production in estuaries with distinct seasonal variations. Here, nitrogen isotopic and isotopomeric signatures were utilized to investigate the seasonal dynamics of NO production and nitrification at the middle reach of the eutrophic Pearl River Estuary in the south of China. Elevated NO production primarily via ammonia oxidation (> 1 nM-N d) occurred from April to November, along with increased temperature and decreased dissolved oxygen concentration. This consistently oxygenated water column showed active denitrification, contributing 20-40 % to NO production. The water column microbial NO production generally constituted a minor fraction (10-15 %) of the estuarine water-air interface efflux, suggesting that upstream transport and tidal dilution regulated the dissolved NO inventory in the middle reach of the estuary. Nitrification (up to 3000 nM-N d) played a critical role in bioavailable nitrogen conversion and NO production, albeit with NO yields below 0.05 %.
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http://dx.doi.org/10.1016/j.marpolbul.2024.116528 | DOI Listing |
Mar Pollut Bull
July 2024
School of Marine Sciences, Sun Yat-Sen University, Zhuhai, China; Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai, China. Electronic address:
Anthropogenic input of excess nutrients stimulates massive nitrous oxide (NO) production in estuaries with distinct seasonal variations. Here, nitrogen isotopic and isotopomeric signatures were utilized to investigate the seasonal dynamics of NO production and nitrification at the middle reach of the eutrophic Pearl River Estuary in the south of China. Elevated NO production primarily via ammonia oxidation (> 1 nM-N d) occurred from April to November, along with increased temperature and decreased dissolved oxygen concentration.
View Article and Find Full Text PDFAnal Chem
February 2024
Biophotonics and Biomedical Engineering Group, Technical University Darmstadt, Merckstr. 25, 64283 Darmstadt, Germany.
Human intervention in nature, especially fertilization, greatly increased the amount of NO emission. While nitrogen fertilizer is used to improve nitrogen availability and thus plant growth, one negative side effect is the increased emission of NO. Successful regulation and optimization strategies require detailed knowledge of the processes producing NO in soil.
View Article and Find Full Text PDFBiomolecules
November 2022
Department of Environment and Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
Mitochondrial (mt) DNA and nuclear (n) DNA have known structures and roles in cells; however, they are rarely compared under specific conditions such as oxidative or degenerative environments that can create damage to the DNA base moieties. Six purine lesions were ascertained in the mtDNA of wild type (wt) CSA (CS3BE-wtCSA) and wtCSB (CS1AN-wtCSB) cells and defective counterparts CS3BE and CS1AN in comparison with the corresponding total (t) DNA (t = n + mt). In particular, the four 5',8-cyclopurine (cPu) and the two 8-oxo-purine (8-oxo-Pu) lesions were accurately quantified by LC-MS/MS analysis using isotopomeric internal standards after an enzymatic digestion procedure.
View Article and Find Full Text PDFJ Inorg Biochem
June 2022
Department of Chemistry and Center for Theoretical and Computational Chemistry, University of Tromsø, N-9037 Tromsø, Norway. Electronic address:
Soret-excited resonance Raman spectra (λ 413.1 nm) were acquired for manganese(III) and gold(III) tris(pentafluorophenyl)corrole, each as four different isotopomeric samples: natural abundance, fully pyrrole-N-substituted, fully meso-C-substituted, and fully pyrrole-N-meso-C-substituted. The spectra were modeled with density functional theory-based vibrational analyses, which in general did an excellent job of reproducing both the absolute frequencies and isotope shifts.
View Article and Find Full Text PDFACS Omega
January 2022
Department of Chemistry, Korea University, Seoul 02841, Korea.
Azides are infrared (IR) probes that are important for structure and dynamics studies of proteins. However, they often display complex IR spectra owing to Fermi resonances and multiple conformers. Isotopic substitution of azides weakens the Fermi resonance, allowing more accurate IR spectral analysis.
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