Research

Buoyancy studies in natural communities of square gas-vacuolate archaea in saltern crystallizer ponds

Aharon Oren¹ , Nuphar Pri-El² , Orr Shapiro³ and Nachshon Siboni³

¹  Department of Plant and Environmental Sciences, The Institute of Life Sciences and the Moshe Shilo Minerva Center for Marine Biogeochemistry, The Hebrew University of Jerusalem, 91904 Jerusalem, Israel

²  Department of Environmental Hydrology & Microbiology, Zuckerberg Institute for Water Research, the Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel

³  Department of Biotechnology Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel

author email corresponding author email

Saline Systems 2006, 2:4doi:10.1186/1746-1448-2-4

Published:	14 April 2006

Abstract

Background

Possession of gas vesicles is generally considered to be advantageous to halophilic archaea: the vesicles are assumed to enable the cells to float, and thus reach high oxygen concentrations at the surface of the brine.

Results

We studied the possible ecological advantage of gas vesicles in a dense community of flat square extremely halophilic archaea in the saltern crystallizer ponds of Eilat, Israel. We found that in this environment, the cells' content of gas vesicles was insufficient to provide positive buoyancy. Instead, sinking/floating velocities were too low to permit vertical redistribution.

Conclusion

The hypothesis that the gas vesicles enable the square archaea to float to the surface of the brines in which they live was not supported by experimental evidence. Presence of the vesicles, which are mainly located close to the cell periphery, may provide an advantage as they may aid the cells to position themselves parallel to the surface, thereby increasing the efficiency of light harvesting by the retinal pigments in the membrane.