PARENT SESSION
Contributed Oral Session 142: Biodiversity and Nitrogen
Thursday, August 11, 1:30 PM - 5:00 PM, Meeting Room 521 A, Level 5, Palais des congrès de Montréal
Response of ammonia oxidizing bacterial communities to nutrient enrichment in a New England salt marsh.
Lage, Melissa*,1, Crain, Caitlin1, Hughes, Jennifer1, 1 Dept. of Ecology and Evolutionary Biology, Providence, RI, USA
ABSTRACT- New England salt marshes, and the diversity of life supported by these ecosystems, are subjected to numerous disturbances from anthropogenic sources. These disturbances significantly alter the plant communities in salt marshes, but little is known about their impact on sediment bacterial communities and thereby belowground ecosystem processes. Here we investigate the response of one component of the bacterial community, the ammonia-oxidizing bacteria (AOB), to nutrient enrichment in a Maine salt marsh. Twenty plots were established in a Spartina patens stand. The plots were subjected to four nutrient treatments: nitrogen, phosphorus, nitrogen plus phosphorous, or control. Nutrients were added regularly for two years. We collected two sediment cores from each plot three times (spring, summer, and fall) for two years. To sample the AOB community, we PCR-amplified an enzymatic gene involved in ammonia oxidation (amoA) and performed terminal restriction fragment length polymorphism (TRFLP) analysis. We found a high AOB richness relative to previous studies, although there was no significant difference in richness between treatments. Preliminary results suggest that nutrients and season interact to effect AOB composition. For instance, AOB communities in the nitrogen plus phosphorous treatment were significantly different than the control treatment, but only in the summer, corresponding with the plant growing season. Understanding the interactions and feedbacks between the plant and bacterial communities is important for predicting changes in marsh functioning as nutrient runoff from anthropogenic activities continues to increase.
Key words: biodiversity, bacteria, Spartina patens