• Anne E. Giblin
  • Craig R. Tobias
  • Bongkeun Song
  • Nathaniel Weston
  • Gary Thomas Banta
  • Victor H. Rivera-Monroy
Until recently, it was believed that biological assimilation and gaseous
nitrogen (N) loss through denitrification were the two major fates of nitrate entering or produced within most coastal ecosystems. Denitrification is often viewed as an important ecosystem service that removes reactive N from the ecosystem. However, there is a competing nitrate reduction process, dissimilatory nitrate reduction to ammonium (DNRA), that conserves N within the ecosystem. The recent application of nitrogen stable isotopes as tracers has generated growing evidence that DNRA is a major nitrogen pathway that cannot be ignored. Measurements comparing the importance of denitrification vs. DNRA in 55 coastal sites found that DNRA accounted for more than 30% of the nitrate reduction at 26 sites. DNRA was the dominant pathway at more than one-third of the sites. Understanding what controls the relative importance of denitrification and DNRA, and how the balance changes with increased nitrogen loading, is of critical importance for predicting eutrophication trajectories. Recent improvements in methods for assessing rates of DNRA have helped refine our understanding of the rates and controls of this process, but accurate measurements in vegetated sediment still remain a challenge.
Original languageEnglish
JournalOceanography
Publication date2013
Volume26
Issue3
Pages124-131
Number of pages8
ISSN1042-8275
DOIs
StatePublished

ID: 40889937