Short-Term Field Observations of Nitrous Oxide Saturations in Lake Taihu, China: The Need for High Temporal Resolution Studies

Document Type

Article

Publication Date

9-1-2010

Department

Marine Science

Abstract

The incomplete understanding of the processes which control aquatic nitrous oxide (N(2)O) production is partially due to a lack of onsite data with which to describe the temporal resolution of N(2)O production. To help resolve this, we directly measured the N(2)O saturation (relative to atmospheric partial pressure) on an hourly basis over two survey periods (July and September 2003) in Lake Taihu, a large eutrophic lake in eastern China. July N(2)O saturations displayed a distinct diurnal pattern, opposite to those observed by others in subtropical streams, but similar to N(2)O emissions observed from incubated estuarine sediments. Correlative analyses indicate that biogeochemical processes operate as important controls on N(2)O production over very short time scales. Nitrous oxide production processes are not only regulated by O(2) dynamics related to microalgal photosynthesis, but also closely related to organic matter decay at the sediment water interface. While large-scale changes (similar to 25-fold) in N(2)O fluxes in Lake Taihu are a function of variable N loading, biogeochemical processes concerning O(2) and N transformation at the sediment water interface have significant (-twofold) impacts on the regulation of N(2)O production over very short time scales. Further, high temporal resolution research focused on developing a comprehensive understanding of lacustrine N(2)O production, including natural and anthropogenic loading and biogeochemical transformation processes, is clearly needed.

Publication Title

Journal of Environmental Quality

Volume

39

Issue

5

First Page

1858

Last Page

1863

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