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