Photoheterotrophy in marine bacteria

Every drop of seawater contains about half a million bacteria, which play crucial roles in the cycles of energy and matter in the oceans. Global warming is predicted to increase the phenomenon of column water stratification, leading to a decrease of nutrients traveling up from depth to surface layer of the ocean. Large ocean regions are becoming less productive because of nutrient depletion. 

Our lab is interested at understanding the physiological and molecular adaptations of heterotrophic marine bacteria to oligotrophic (nutrient poor) conditions. Our study site is the Eastern Mediterranean Sea, the largest body of water that is severely depleted in phosphate. Recent studies suggest that the Eastern Mediterranean Sea behaves in a similar way to the open ocean gyres with respect to nutrient supply and ultra-oligotrophic conditions. Every year wide temperature fluctuations result in summer water stratification and shifts in composition and function of the microbial community. 

Our studies begin at Sea, where we determine microbial community structure and function by diverse sets of -omics techniques. We then proceed our work in the lab, where, through isolation of novel bacterial cultures, we investigate the physiology and genomics of important members of the marine microbial community. 

One topic we study is the utilization of the light-activated proteorhodopsin protein by heterotrophic bacteria. This mechanism can enable bacteria to thrive in ultraoligotrophic conditions by reducing the cellular consumption of exogenous carbon for energy production.