Biodiversity of the nitrogen-fixing microbes of the Antarctic origin

Nitrogen fixation is essential because it is the only way that organisms can attain nitrogen directly from the atmosphere. Nitrogen-fixing bacteria can exist either in the form of symbiotic relationships with host plants or as free-living nitrogen fixers. In aquatic environments, blue - green alga is an important free-living nitrogen fixer. Cyanobacteria are also one of very few groups of organisms that can convert inert atmospheric nitrogen into an organic form, such as nitrate or ammonia.
The specific objectives of the project:
• To isolate and characterize new N2-fixing and denitrification microorganisms and to detect new genetic information involved in nitrogen fixation and denitrification.
• To study the biodiversity denitrification genes using a molecular approach
• To localize the microhabitat of N2-fixing and denitrifying microorganisms in selected Antarctic ecosystems to focus isolation strategies on that size fraction.

Water samples were collected using Wiscosin plankton nets with a 30 μm mesh-size. A total of 40 L of water were filtered through the plankton net. Samples were then preserved with Lugol’s iodine solution and 5% formalin buffer. All samples will be transferred to the laboratory for further cell counting and identification using microscopic examination. Cyanobacterial identification and enumeration from the plankton samples will be carried out.