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Updated: Jun 9, 2025

Single-throughput Complementary High-resolution Analytical Techniques for Characterizing Complex Natural Organic Matter Mixtures
Published on: January 7, 2019
Labile organic matter favors a low N2O yield during nitrogen removal in estuarine sediments
Ehui Tan1, Bin Chen2, Lili Han1
1State Key Laboratory of Marine Resource Utilization in South China Sea, School of Marine Science and Engineering, Hainan University, Haikou, Hainan, China.
Abstract:
Estuary harbors the active sediment denitrification and nitrous oxide (N2O) emission, while the knowledge of environmental controls on the denitrification-derived N2O yield remains underexplored. Here, we quantitatively assess the potential and in situ rates of N2O production during sediment denitrification in the Pearl River Estuary (PRE), China. Organic matter determines the product stoichiometry and capacity of nitrogen removal. In particular, labile organic matter (LOM) reduces N2O yield via enhancing the complete coupled nitrification-denitrification. Our results reveal that the chain processes, primary production-LOM settling-sedimentary respiration-coupled nitrification-denitrification, control the sediment denitrification and N2O production, linking the carbon and nitrogen biogeochemical cycles in the atmosphere-water column-sediment continuum. The PRE sediments serve as nitrogen removal hotspots but with low efficiency (~25 % of riverine input) and strong N2O release (~66 % of daily sea-air N2O efflux). These findings contribute to policy makers to develop knowledge-based management actions for achieving sustainable coastal environments and mitigating N2O emission.
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