期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：17
页码：4330-4335
DOI：10.1073/pnas.1617454114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Riverine environments, such as streams and rivers, have been reported as sources of the potent greenhouse gas nitrous oxide ( N 2 O ) to the atmosphere mainly via microbially mediated denitrification. Our limited understanding of the relative roles of the near-surface streambed sediment (hyporheic zone), benthic, and water column zones in controlling N 2 O production precludes predictions of N 2 O emissions along riverine networks. Here, we analyze N 2 O emissions from streams and rivers worldwide of different sizes, morphology, land cover, biomes, and climatic conditions. We show that the primary source of N 2 O emissions varies with stream and river size and shifts from the hyporheic–benthic zone in headwater streams to the benthic–water column zone in rivers. This analysis reveals that N 2 O production is bounded between two N 2 O emission potentials: the upper N 2 O emission potential results from production within the benthic–hyporheic zone, and the lower N 2 O emission potential reflects the production within the benthic–water column zone. By understanding the scaling nature of N 2 O production along riverine networks, our framework facilitates predictions of riverine N 2 O emissions globally using widely accessible chemical and hydromorphological datasets and thus, quantifies the effect of human activity and natural processes on N 2 O production.
关键词：riverine networks ; greenhouse gas ; N2O ; emission scaling law ; N2O emission potentials
