Novel phototrophy potential in microbial mats

Phototrophy is a critical pathway for carbon and energy flow in microbial mat systems, and new discoveries by our group have demonstrated that the limit for oxygenic photosynthesis is broader than originally known. We hypothesise that light and phototrophic metabolisms are major drivers affecting ecosystem function in modern mats, and that photosynthetic microbes below the surface possess unique adaptations to lower light conditions. Together with collaborator Tony Larkum, preliminary data suggest the presence of novel photosynthetic pigments in these systems, absorbing in the far-infrared region. This is of significance as it broadens the limits for oxygenic photosynthesis than previously thought. Our recent work suggests some photrophs actually increase with depth in these ecosystems, and this was hypothesised to be linked to different spectral niches that may exist within and below the photic zone. Despite these advances in the understanding of the Shark Bay microbial mats, more in-depth analyses are required to truly characterise the extent and importance of phototrophic metabolisms in these evolutionary significant ecosystems. Using a range of approaches we are targeting novel phototrophs, their pigments, and related pathways in several mat systems in Shark Bay, including a relatively uncharacterised site at Blue Holes.