Open AccessAbundance and diversity of organohalide‐respiring bacteria in lake sediments across a geographical sulfur gradient
Author(s) -
Krzmarzick Mark J.,
McNamara Patrick J.,
Crary Benjamin B.,
Novak Paige J.
Publication year - 2013
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/1574-6941.12059
Subject(s) - biology , terminal restriction fragment length polymorphism , sulfur , sulfate , chloroflexi (class) , transect , sediment , environmental chemistry , ecology , restriction fragment length polymorphism , 16s ribosomal rna , bacteria , proteobacteria , polymerase chain reaction , chemistry , biochemistry , paleontology , genetics , organic chemistry , gene
Across the U . S . U pper M idwest, a natural geographical sulfate gradient exists in lakes. Sediment grab samples and cores were taken to explore whether this sulfur gradient impacted organohalide‐respiring C hloroflexi in lake sediments. Putative organohalide‐respiring C hloroflexi were detected in 67 of 68 samples by quantitative polymerase chain reaction. Their quantities ranged from 3.5 × 10 4 to 8.4 × 10 10 copies 16 S r RNA genes g −1 dry sediment and increased in number from west to east, whereas lake sulfate concentrations decreased along this west‐to‐east transect. A terminal restriction fragment length polymorphism ( TRFLP ) method was used to corroborate this inverse relationship, with sediment samples from lower sulfate lakes containing both a higher number of terminal restriction fragments ( TRF s) belonging to the organohalide‐respiring D ehalococcoidetes , and a greater percentage of the TRFLP amplification made up by D ehalococcoidetes members. Statistical analyses showed that dissolved sulfur in the porewater, measured as sulfate after oxidation, appeared to have a negative impact on the total number of putative organohalide‐respiring C hloroflexi , the number of D ehalococcoidetes TRF s, and the percentage of the TRFLP amplification made up by D ehalococcoidetes . These findings point to dissolved sulfur, presumably present as reduced sulfur species, as a potentially controlling factor in the natural cycling of chlorine, and perhaps as a result, the natural cycling of some carbon as well.