In situ microcosms to evaluate natural attenuation potentials in contaminated aquifers

Phospholipid fatty acids (PLFA) of living cells make up a significant part of the total lipid fatty acid (TLFA) fraction. Comparing BACTRAPs exposed at different geochemical zones of the aquifers, the fatty acid composition was found to be relatively similar indicating that the composition of the TLFA was of low taxonomic value and not sensitive enough for a community analysis. Therefore the composition of the microbial communities was analysed by genetic profiling and sequencing of partial 16S rRNA genes PCR-amplified from total DNA, extracted directly from the BACTRAPs. Sequences retrieved from the BACTRAPs indicated a dominance of not-yet cultivated bacteria, with several of them phylogenetically closely related to those with an iron and sulphate reducing capacity, typically found at BTEX and mineral oil polluted sites.