Thermotolerant Zymomonas mobilis: Comparison of ethanol fermentation capability with that of an efficient type strain

The ice edge of the Barents Sea east of Svalbard is an area where the warm, salty water of the North Atlantic (AtW) interacts with cold, less dense, saline Arctic water (ArW) and the water produced by melting ice (MIW). Many of the CTD profiles (CTD stands for Conductivity-Temperature-Depth) obtained in this region by Norwegian Polar Institute expeditions in 1999 and 2007 contain layers that are quasi-homogeneous in temperature, salinity and density between the depths of 5-7 m to 100-150 m. It is shown that these features are formed by convective instability due to double-diffusion, which can occur where there are positive vertical gradients of both temperature and salinity, as is observed in this region. The rate of development and the thickness of the gradient layer depend on vertical temperature and salinity drops in the zone of interaction of AtW with ArW and MIW. They correspond well, characterized by a correlation coefficient of 0.96.