Title |
Denitrification Potential and Denitrifier Abundance in Downstream of Dams in Temperate Streams |
Author |
Nguyen Xuan Que Vo, Seung-Hoon Lee, Tuan Van Doan, Sokhee P. Jung, and Hojeong Kang* |
Address |
Yonsei University |
Bibliography |
Korean Journal of Microbiology, 50(2),137-151, 2014 |
DOI |
http://dx.doi.org/10.7845/kjm.2014.4021
|
Key Words |
denitrification enzyme activity, denitrifier abundance, nitrogen cycle, stream regulation |
Abstract |
Various studies have been conducted to investigate effects of dams on river ecosystems, but less information is
available regarding damming impacts on downstream denitrification. We measured denitrification enzyme activity
(potential denitrification rate) and denitrifier abundances (using nirS, nirK, and nosZ as markers) in dammed
headstreams of the Nakdong River in South Korea. Sediments in Phragmites-dominated riparian areas and in-stream
areas across streams (dammed vs. reference) with different streambed materials (gravel and sand) were sampled
occasionally. We hypothesized that (i) the higher available N and C contents in sediments downstream of dams foster
larger denitrifier communities than in the reference system and (ii) differences in potential denitrification rates across
the systems correspond with denitrifier abundances. Despite 30 years of different hydrological management with
dams and greater inorganic N and DOC contents in sediments downstream of dams, compared to the references,
abundances of denitrifier communities and potential denitrification rates within the whole sediment were not
significantly different across the systems. However, nirS and nosZ denitrifier abundances and potential
denitrification rates were considerably increased in specific sediments downstream of dams (gravelly riparian and
sandy in-stream) with regard to flooding events and seasonal temperature variation. nirK was not amplified in all
sediments. Canonical correspondence analyses (CCA) revealed that the relationship between abundances of
denitrifier communities and nutrient availabilities and potential denitrification rates was a weak one. |
Download PDF |
50(2)_08_p.137-151.pdf |