Publication Detail

Characterizing microbial denitrification and biogeochemical processes up-gradient, within, and down-gradient from a NITREX™ permeable reactive barrier in Waquoit Bay, MA

Collin Knauss, Kenly Hiller, Patrick Kearns, Sarah Feinman, Jennifer L. Bowen
1 pp.
MITSG 13-36
$5.50 DOM / $7.50 INT

In 2005, a wood-chip based NITREXTM permeable reactive barrier (PRB) designed to remove nitrate via microbial denitrification was installed to intercept groundwater entering Waquoit Bay, MA, a moderately eutrophic estuarine system. In this experiment we took 27 groundwater samples from an array of multi-depth sampling wells distributed at 8 locations up-gradient, down-gradient, within, and underneath the experimental PRB. We also took 18 groundwater samples from control wells adjacent to the PRB. Microbial DNA was extracted and the 16S rDNA gene was PCR amplified and analyzed for total microbial diversity using denaturing gradient gel electrophoresis (DGGE). Additional samples were analyzed for a suite of biogeochemical parameters. The PRB effectively reduced nitrates from a maximum up-gradient concentration of 70 μM to below 5 μM within and down-gradient of the PRB as opposed to consistently high nitrate concentrations in the control site (>100 uM). There was also a presence of distinct microbial communities among the sites with a 50% similarity between up-gradient PRB samples and control samples and a 60% similarity among samples within the PRB.

type: Presentations

Parent Project

Project No.: 2012-R/RC-129
Title: Microbial community composition of permeable reactive barriers: who is really doing the work?