Bacterioplankton assemblages in maritime Antarctic freshwater lakes, as determined by denaturing gradient gel electrophoresis (DGGE)

SCHIAFFINO, M. R.; UNREIN, F.; MASSANA, R.; GASOL, J. M.; FARIAS, M. E.; ESTEVEZ, C.; BALAGUÉ, V.; IZAGUIRRE, I.

St. John’s, Newoundland (Canada)

Congreso; ASLO Summer Meeting 2008; 2008

ASLO

Bacterioplankton assemblages of freshwater lakes with contrasting trophic status located in two regions of Maritime Antarctica (Hope Bay, Antarctic Peninsula and King George Island) were analysed by DGGE. These lakes were sampled during two austral summers (2003–2004). Some of the sequences shared among lakes from Hope Bay were also found in lakes from Potter Peninsula. However, some sequences appeared exclusively in specific lakes, which seem to be related to the local conditions and lake trophic status. Other sequences were found only in three connected oligotrophic lakes from Hope Bay. The best represented bacterial group in all lakes was Cytophaga-Flavobacterium-Bacteroidetes (48 %), followed by Actinobacteria (30 %), beta-Proteobacteria (15 %) and Cyanobacteria (7 %). Interestingly, many of the sequences showed high similarity with psychrophilic and psychrotolerant bacteria, which suggests bacterial assemblages well adapted to low-temperature aquatic systems and glaciers, not only from different areas of Antarctica but also from elsewhere in the world. This work reports the first description of the bacterioplankton assemblages in these maritime Antarctic freshwater lakes as determined by a molecular fingerprinting technique.