TY - JOUR
T1 - Wide distribution of autochthonous branched glycerol dialkyl glycerol tetraethers (bGDGTs) in U.S. Great Basin hot springs
AU - Hedlund, Brian P.
AU - Paraiso, Julienne J.
AU - Williams, Amanda J.
AU - Huang, Qiuyuan
AU - Wei, Yuli
AU - Dijkstra, Paul
AU - Hungate, Bruce A.
AU - Dong, Hailiang
AU - Zhang, Chuanlun L.
PY - 2013
Y1 - 2013
N2 - Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likelystabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs areknown to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S.Great Basin (temperature: 31-95°C; pH: 6.8-10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration ofbGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS-) and positively with properties ofoxygenated, low temperature sites (O2, NO-3). Two-way cluster analysis and nonmetric multidimensionalscaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (=70°C).
AB - Branched glycerol dialkyl glycerol tetraethers (bGDGTs) are membrane-spanning lipids that likelystabilize membranes of some bacteria. Although bGDGTs have been reported previously in certain geothermal environments, it has been suggested that they may derive from surrounding soils since bGDGTs areknown to be produced by soil bacteria. To test the hypothesis that bGDGTs can be produced by thermophiles in geothermal environments, we examined the distribution and abundance of bGDGTs, along with extensive geochemical data, in 40 sediment and mat samples collected from geothermal systems in the U.S.Great Basin (temperature: 31-95°C; pH: 6.8-10.7). bGDGTs were found in 38 out of 40 samples at concentrations up to 824 ng/g sample dry mass and comprised up to 99.5% of total GDGTs (branched plus isoprenoidal). The wide distribution of bGDGTs in hot springs, strong correlation between core and polar lipid abundances, distinctness of bGDGT profiles compared to nearby soils, and higher concentration ofbGDGTs in hot springs compared to nearby soils provided evidence of in situ production, particularly for the minimally methylated bGDGTs I, Ib, and Ic. Polar bGDGTs were found almost exclusively in samples ≤70°C and the absolute abundance of polar bGDGTs correlated negatively with properties of chemically reduced, high temperature spring sources (temperature, H2S/HS-) and positively with properties ofoxygenated, low temperature sites (O2, NO-3). Two-way cluster analysis and nonmetric multidimensionalscaling based on relative abundance of polar bGDGTs supported these relationships and showed a negative relationship between the degree of methylation and temperature, suggesting a higher abundance for minimally methylated bGDGTs at high temperature. This study presents evidence of the widespread production of bGDGTs in mats and sediments of natural geothermal springs in the U.S. Great Basin, especially in oxygenated, low-temperature sites (=70°C).
KW - Geothermal springs
KW - Great basin
KW - Lipids
KW - Membrane-spanning lipids
KW - Thermophiles
KW - bGDGTs
UR - http://www.scopus.com/inward/record.url?scp=84884260270&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84884260270&partnerID=8YFLogxK
U2 - 10.3389/fmicb.2013.00222
DO - 10.3389/fmicb.2013.00222
M3 - Article
C2 - 23964271
AN - SCOPUS:84884260270
SN - 1664-302X
VL - 4
JO - Frontiers in Microbiology
JF - Frontiers in Microbiology
IS - AUG
ER -