By metagenomics, he discovered the first marine microbial rhodopsin in an abundant yet uncultured marine bacterium; proteorhodopsins in the SAR86 group (Béjà, et al. Science (2000)). Later on he found that marine microbial rhodopsins are spectrally tuned to the light that is found in the depth the rhodopsins are isolated from (Béjà, et al. Nature (2001)). In 2002, using the same metagenomic approach, he found the microbial players in oceanic aerobic anoxygenic photosynthesis (Béjà, et al. Nature (2002)). Another field that the lab is exploring is viral ‘photosynthesis’. In 2005 his-group discovered the first environmental viral photosystem-II genes (Zeidner et al. Environ. Microbiol. (2005)), and in 2009, using metagenomics, the first viral photosystem-I viral genes (Sharon et al. Nature (2009)). Recently, they also reported that enhancement of cyclic electron flow occurs in infected cyanobacterial cell (Fridman et al. Nature Micolbiol. (2017)).