Denitrifer Activity and Community Composition in Reciprocal Transfers Between Forests and Meadows in the Cascade Mountains of Oregon. (3568)
Authors:
S.A. Boyle* - Oregon State Univ.
J.J. Rich - Oregon State Univ.
P.J. Bottomley - Oregon State Univ.
K. Cromack, Jr. - Oregon State Univ.
D.D. Myrold - Oregon State Univ.
Abstract:
Natural and manmade disturbance has created a series of small meadows that are interspersed among the forests of the Oregon Cascades. These clearings provide unique opportunities to study the effects of vegetation on adjacent soil microbial communities and to examine the changes in soil processes between the forest and meadow ecosystem. In order to investigate the changes in denitrification enzyme activity and denitrifying community composition, soil cores were reciprocally transferred between meadow and forest samples. Treatments included remaining cores to test disturbance affects and open/closed cores that examined root
inclusion/exclusion. Soil cores were transferred in September 2000 and collected in September of 2001 and 2002. Denitrification enzyme activities were measured using soil slurries, and community composition was determined using nosZ (nitrous oxide reductase) primers. DNA extracts were amplified and digested with
restriction enzymes to generate T-RFLP profiles. Resulting T-RFLP profiles were analyzed for possible shifts in the denitrifier communities. Denitrification activity increased when cores were moved from the meadow to the forest and when roots were included (open cores). Denitrifying communities did not change in response to treatment effects, but year to year variations were observed. Data suggest that
denitrifying community composition may be uncoupled from enzyme activities in this system.
Speaker Information: Stephanie Boyle, Oregon State Univ., Soil Science Dept. 3017 ALS Bldg, Corvallis, OR 97330; Phone: 541 737 4517; E-mail:
Session Information: Tuesday, November 2, 2004, 8:00 AM-10:00 AM Presentation Start: 8:00 AM (Poster Board Number: 2616)