TY - JOUR
T1 - Dominance of a clonal green sulfur bacterial population in a stratified lake
AU - Gregersen, Lea H
AU - Habicht, Kirsten S
AU - Peduzzi, Sandro
AU - Tonolla, Mauro
AU - Canfield, Donald E
AU - Miller, Mette
AU - Cox, Raymond P
AU - Frigaard, Niels-Ulrik
N1 - KEYWORDS
Chlorobium • clonal population • bloom • green sulfur bacteria • Lake Cadagno
PY - 2009
Y1 - 2009
N2 - For many years, the chemocline of the meromictic Lake Cadagno, Switzerland, was dominated by purple sulfur bacteria. However, following a major community shift in recent years, green sulfur bacteria (GSB) have come to dominate. We investigated this community by performing microbial diversity surveys using FISH cell counting and population multilocus sequence typing [clone library sequence analysis of the small subunit (SSU) rRNA locus and two loci involved in photosynthesis in GSB: fmoA and csmCA]. All bacterial populations clearly stratified according to water column chemistry. The GSB population peaked in the chemocline (c. 8 x 10(6) GSB cells mL(-1)) and constituted about 50% of all cells in the anoxic zones of the water column. At least 99.5% of these GSB cells had SSU rRNA, fmoA, and csmCA sequences essentially identical to that of the previously isolated and genome-sequenced GSB Chlorobium clathratiforme strain BU-1 (DSM 5477). This ribotype was not detected in Lake Cadagno before the bloom of GSB. These observations suggest that the C. clathratiforme population that has stabilized in Lake Cadagno is clonal. We speculate that such a clonal bloom could be caused by environmental disturbance, mutational adaptation, or invasion.
AB - For many years, the chemocline of the meromictic Lake Cadagno, Switzerland, was dominated by purple sulfur bacteria. However, following a major community shift in recent years, green sulfur bacteria (GSB) have come to dominate. We investigated this community by performing microbial diversity surveys using FISH cell counting and population multilocus sequence typing [clone library sequence analysis of the small subunit (SSU) rRNA locus and two loci involved in photosynthesis in GSB: fmoA and csmCA]. All bacterial populations clearly stratified according to water column chemistry. The GSB population peaked in the chemocline (c. 8 x 10(6) GSB cells mL(-1)) and constituted about 50% of all cells in the anoxic zones of the water column. At least 99.5% of these GSB cells had SSU rRNA, fmoA, and csmCA sequences essentially identical to that of the previously isolated and genome-sequenced GSB Chlorobium clathratiforme strain BU-1 (DSM 5477). This ribotype was not detected in Lake Cadagno before the bloom of GSB. These observations suggest that the C. clathratiforme population that has stabilized in Lake Cadagno is clonal. We speculate that such a clonal bloom could be caused by environmental disturbance, mutational adaptation, or invasion.
U2 - 10.1111/j.1574-6941.2009.00737.x
DO - 10.1111/j.1574-6941.2009.00737.x
M3 - Journal article
C2 - 19656193
SN - 0168-6496
VL - 70
SP - 30
EP - 41
JO - F E M S Microbiology Ecology
JF - F E M S Microbiology Ecology
IS - 1
ER -