Xenobiotic Degradation by Denitrifying Bacteria in Intertidal Microbial Mats.
CALIFORNIA UNIV SANTA CRUZ
Pagination or Media Count:
Two estuaries on the central California coast, Tomales Bay and Elkhorn Slough, which harbor well developed microbial mats in the intertidal region were chosen as experimental sites. At both sites, we investigated denitrification, benzoate degradation and bacterial production rate processes of the intact community whole cores. At Elkhorn Slough, we used a newly designed flow-through incubator to assess bacterial community acclimation to challenge from xenobiotics, using 2,4-D as a model. The simulated in situ incubation apparatus was used to 1 measure integrated total secondary production within the mats and 2 determine the ability of the consortium to transform xenobiotic compounds and assess the changes which occur during acclimation of the mat to xenobiotic exposure. An immuno-magnetic bead separation method was optimized for measuring species specific bacterial production, using a marine denitrifying strain to demonstrate the approach. The diversity of denitrifying bacteria, including several isolated from Tomales Bay mats, was investigated using RFLP analysis and probes for nitrite reductase. Quantitative, non-radioactive, hybridization methods for measurement of gene abundance were developed and used to quantify nitrite reductase and xy1E in mm scale depth profiles in the sediments at the study sites.