Human land uses enhance sediment denitrification and N<sub>2</sub>O production in Yangtze lakes primarily by influencing lake water quality
Sediment denitrification in lakes alleviates the effects of eutrophication through the removal of nitrogen to the atmosphere as N<sub>2</sub>O and N<sub>2</sub>. However, N<sub>2</sub>O contributes notably to the greenhouse effect and global warming. Human land us...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2015-10-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/12/6059/2015/bg-12-6059-2015.pdf |
| Summary: | Sediment denitrification in lakes alleviates the effects of eutrophication
through the removal of nitrogen to the atmosphere as N<sub>2</sub>O and N<sub>2</sub>.
However, N<sub>2</sub>O contributes notably to the greenhouse effect and global
warming. Human land uses (e.g. agricultural and urban areas) strongly
affect lake water quality and sediment characteristics, which, in turn, may
regulate lake sediment denitrification and N<sub>2</sub>O production. In this
study, we investigated sediment denitrification and N<sub>2</sub>O production and
their relationships to within-lake variables and watershed land uses in 20
lakes from the Yangtze River basin in China. The results indicated that both
lake water quality and sediment characteristics were significantly
influenced by watershed land uses. N<sub>2</sub>O production rates increased with
increasing background denitrification rates. Background denitrification and
N<sub>2</sub>O production rates were positively related to water nitrogen
concentrations but were not significantly correlated with sediment
characteristics and plant community structure. A significant positive
relationship was observed between background denitrification rate and
percentage of human-dominated land uses (HDL) in watersheds. Structural
equation modelling revealed that the indirect effects of HDL on sediment
denitrification and N<sub>2</sub>O production in Yangtze lakes were mediated
primarily through lake water quality. Our findings also suggest that
although sediments in Yangtze lakes can remove large quantities of nitrogen
through denitrification, they may also be an important source of N<sub>2</sub>O,
especially in lakes with high nitrogen content. |
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| ISSN: | 1726-4170 1726-4189 |