Irkutsk, Russia – Bacteriophages in Lake Baikal
Water has always played a huge part in the balance and development of life. Apart from the aquatic ecosystem being vital for the survival of species, there may be an even greater potential that is found in it, that we are just beginning to discover.
Aquatic ecosystems and bacteriophages
Researchers have begun looking into the high number of bacteriophages found in seas and oceans since the end of the last century. Due to the rapid reproduction of phages, that undergo the lytic cycle, bacteriophages have a large impact on the global processes and overall ecosystem of oceans and seas.
Recent findings from the scientists at the Limnological Institute in Irkutsk, have shown that a large number of indigenous bacteriophages were found in the aquatic ecosystem of the Lake Baikal. The Baikal still remains to have the cleanest water in the world, when seen from the aspect of bacterial contamination.
Lake Baikal and bacteriophages
Lake Baikal, one of the largest freshwater lakes in the world, contains numerous amounts of bacteriophages. In 1997, Irkutsk hydro biologists began their research with the coli phages, bacteriophages that infect Escherichia coli. In 2002, with the method of transmission electron microscopy, a systematic study of the Baikal bacteriophages began. They were studying their size, structure and the total number that were present during different seasons, as well as those present at different depths (up to 1200m). Studies were also made into bacteriophages at boundary phases; air – water, water – bottom of lake.
It has taken the scientists 20 years to be able to recreate a complete picture of the life in the Baikal lake, with the following findings;
Size – The predominant bacteriophages are those of size between 30-80nm, following are those larger than 100nm.
Seasons & boundary phases – The bacteriophages were observed to be found on the surface of the water mostly during spring and summer-autumn. During winter the surface of the water had the minimum amount, found on the depth of 1000m.
The most interesting observation was that they found bacteriophages which are absent from the modern international classification and have not been described to be in any other aquatic ecosystems. Molecular biologists are studying the Lake Baikal bacteriophages, particularly the uniqueness of some, as these may aid in future medical and biotechnological research.
Lake Baikal findings
With the above research, the genome of the Baikal novel giant bacteriophage, PaBG has been completely decoded and is now registered in GenBank (#KF147891). What is most impressive findings of the Irkutsk scientists, is according to their findings, the number of particles free from bacteriophages found in the water during different seasons. This varied between 10 (in 4 degrees Celsius) to 5.8 (in 5 degrees Celsius) particles per ml. In winter, the minimum was found at the lake’s depth and the maximum found during summer on the surface layer.
Since bacteriophages target bacteria, the findings show that from a bacterial contamination perspective, the Lake Baikal is cleaner by almost one million times in winter and 50 to 100 times in summer, than the ocean. These results show the importance and responsibility we hold in making sure to preserve and protect such unique lakes, such as the Lake Baikal.