Habitat partitioning of denitrifying bacterial communities carrying nirS or nirK genes in the stratified water column of Lake Kinneret, Israel

摘要

The community composition of denitrifying bacteria was studied in the stratified water column of Lake Kinneret. The nitrite reductase genes and were amplified by PCR from water samples taken at 1, 14, 19 and 22 m depth, which represent the epi-, meta- and hypolimnion of the lake. The PCR products were analyzed with terminal restriction fragment length polymorphism (T-RFLP) and clone libraries. The highest diversity of denitrifying communities was observed at 1 m depth. According to the T-RFLP profiles and clone libraries of products, 2 groups of denitrifiers were common to and dominant in all depths. Deduced protein sequences from one of these groups displayed low identity (77%) with other sequences reported in GenBank. Denitrifying bacterial communities with were most diverse at 22 m and showed highest similarity to those at 19 m depth. Sequences unrelated to dominated the clone libraries from 1 m depth, suggesting that denitrifying bacteria with copper-containing nitrite reductase were less frequent at this depth. The results suggest that microorganisms with and those with respond differently to the environmental conditions in the stratified water column of Lake Kinneret.