PARENT SESSION
Monday, August 7, 5:00-6:30 pm
Poster Session 4 - Soil, mycorrhizal, and microbial ecology
Exhibit Hall, Ballroom Level, Cook Convention Center
Assessing microbial communities in treatment wetlands as affected by phosphorus loading - a microcosm experiment.
Ahn, Changwoo*,, Gillevet, Patrick1, Sikaroodi, Masoumeh2, 1 George Mason University, Fairfax, VA2
ABSTRACT- Biogeochemical processes and phosphorus removal in constructed wetlands have been extensively studied over the past thirty years. However, little is known about microbial communities in constructed wetlands and how those communities respond to the biogeochemical and phosphorus gradients. We conducted a microcosm wetland study and collected basic data on microbial community structure and diversity of sediment samples taken under different environmental conditions (i.e., macrophyte and phosphorus loading). The study attempted to examine the influence of macrophytes and phosphorus loading that is critical in treatment efficiency of constructed wetlands on microbial community structure and diversity. Specifically, we fingerprinted sediments obtained from wetland microcosms using Length Heterogeneity PCR (LH-PCR) and examined microbial diversity of the sediments by cloning and sequencing community libraries. Three-dimensional principal coordinate analysis (PCO) analysis of the fingerprints suggested that phosphorus loading has a significant impact in altering soil microbial community structure. LH-PCR products from the high- and low-phosphorus control groups were cloned and then sequenced. The results of cloning also showed that a small number of the bacterial groups favored one of the phosphorus treatments over the other. Of these groups, the Sphingomonas genus of bacteria was among the most selective. Further investigation is needed to study the linkages between sediment microbial community signatures and soil phosphorus dynamics in regard to water quality function of treatment wetlands.
Key words: constructed wetland, microbial community, LH-PCR