Photosynthesis under Red Dwarf star light: exploring the limits of PAR radiation

The recent discovery of a number of rocky exoplanets orbiting in the habitable zone of their Red Dwarf stars is offering new challenges to answer the question whether life could be possible in other worlds beyond our solar system. In this frame in Padova is active an interdisciplinary collaboration between researchers of the Department of Biology, the Astronomical Observatory (INAF) and the Institute of Photonics and Nanotechnology (IFNCNR). A light simulator capable of reproducing different stellar spectra and an atmosphere simulation chamber have been developed. The growth and photosynthetic performances of selected microorganisms irradiated with Red Dwarf star or solar simulated lights have been analyzed. Experiments were carried out with photosynthetic organisms selected between cyanobacteria strains recently demonstrated to be able to perform both far-red and low light acclimation, due to the presence of peculiar chlorophyll forms (chl d and f)1 and phycobilisomes organization. Preliminary results of this pioneering experiment, on the possibility of oxygenic photosynthesis in habitable planets irradiated by M stars, will be presented. Their importance for remote detection of exotic life will be discussed. References 1. Gan & Bryant 2015 Environmental Microbiology 17(10):3450-65