TY - JOUR
T1 - Euxinic Freshwater Hypolimnia Promote Bacterial Endemicity in Continental Areas
AU - Barberán, Albert
AU - Casamayor, Emilio O.
N1 - Funding Information:
We are thankful to authors who provided valuable data for the analysis and to two anonymous reviewers for their constructive comments. This research was supported by grant AERBAC 079/2007 from the Spanish Ministerio de Medio Ambiente (MARM) and grants CONSOLIDER-INGENIO 2010 GRACCIE CSD2007-00067 and PIRENA CGL2009-13318-CO2-01/BOS from the Spanish Ministerio de Ciencia e Innovación (MICINN) to EOC. AB is supported by the Spanish FPU predoctoral scholarship program.
PY - 2011/2
Y1 - 2011/2
N2 - Bacteria and archaea represent the vast majority of biodiversity on Earth. The ways that dynamic ecological and evolutionary processes interact in the microbial world are, however, poorly known. Here, we have explored community patterns of planktonic freshwater bacteria inhabiting stratified lakes with oxic/anoxic interfaces and euxinic (anoxic and sulfurous) water masses. The interface separates a well-oxygenated upper water mass (epilimnion) from a lower anoxic water compartment (hypolimnion). We assessed whether or not the vertical zonation of lakes promoted endemism in deeper layers by analyzing bacterial 16S rRNA gene sequences from the water column of worldwide distributed stratified lakes and applying a community ecology approach. Community similarity based on the phylogenetic relatedness showed that bacterial assemblages from the same water layer were more similar across lakes than to communities from different layer within lakes and that anoxic hypolimnia presented greater β-diversity than oxic epilimnia. Higher β-diversity values are attributable to low dispersal and small connectivity between community patches. In addition, surface waters had significant spatial but non-significant environmental components controlling phylogenetic β-diversity patterns, respectively. Conversely, the bottom layers were significantly correlated with environment but not with geographic distance. Thus, we observed different ecological mechanisms simultaneously acting on the same water body. Overall, bacterial endemicity is probably more common than previously thought, particularly in isolated and environmentally heterogeneous freshwater habitats. We argue for a microbial diversity conservation perspective still lacking in the global and local biodiversity preservation policies.
AB - Bacteria and archaea represent the vast majority of biodiversity on Earth. The ways that dynamic ecological and evolutionary processes interact in the microbial world are, however, poorly known. Here, we have explored community patterns of planktonic freshwater bacteria inhabiting stratified lakes with oxic/anoxic interfaces and euxinic (anoxic and sulfurous) water masses. The interface separates a well-oxygenated upper water mass (epilimnion) from a lower anoxic water compartment (hypolimnion). We assessed whether or not the vertical zonation of lakes promoted endemism in deeper layers by analyzing bacterial 16S rRNA gene sequences from the water column of worldwide distributed stratified lakes and applying a community ecology approach. Community similarity based on the phylogenetic relatedness showed that bacterial assemblages from the same water layer were more similar across lakes than to communities from different layer within lakes and that anoxic hypolimnia presented greater β-diversity than oxic epilimnia. Higher β-diversity values are attributable to low dispersal and small connectivity between community patches. In addition, surface waters had significant spatial but non-significant environmental components controlling phylogenetic β-diversity patterns, respectively. Conversely, the bottom layers were significantly correlated with environment but not with geographic distance. Thus, we observed different ecological mechanisms simultaneously acting on the same water body. Overall, bacterial endemicity is probably more common than previously thought, particularly in isolated and environmentally heterogeneous freshwater habitats. We argue for a microbial diversity conservation perspective still lacking in the global and local biodiversity preservation policies.
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U2 - 10.1007/s00248-010-9775-6
DO - 10.1007/s00248-010-9775-6
M3 - Article
C2 - 21107832
AN - SCOPUS:79951517955
SN - 0095-3628
VL - 61
SP - 465
EP - 472
JO - Microbial ecology
JF - Microbial ecology
IS - 2
ER -