Stromatolites at Shark Bay, Western Australia. Image by C Eeckhout (Wikimedia Commons)Photosynthesis is great. Plants (and some bacteria) use some CO₂, some H₂O, and a bit of sunlight to build themselves. The sunlight involved is mainly within the visible range of the electromagnetic spectrum, especially around 430 nanometres (violet) and 660 nanometres (red).

When I say “some bacteria”, I refer to cyanobacteria. These fabulous organisms are believed to have triggered a huge boost in early biodiversity when they started photosynthesising (about 3.5 billion years ago), absorbing CO₂ and releasing O₂. It looks like these guys have been keeping a pretty special secret.

Some of those early cyanobacteria are still around today. In a few choice locations around the world (for example Shark Bay in Western Australia) you can see living stromatolites, rock-like structures built up by microorganisms – especially cyanobacteria. If you do drop by for a visit, you might wonder how light reaches the cyanobacteria deep inside the stromatolite. Certainly light in the visible region of the electromagnetic spectrum would not penetrate that far. Well the compound that actually absorbs the light is chorophyll and a team from the Universities of Sydney, New South Wales, Munich as well as Macquarie University have discovered a brand new – but very old - form of chrorphyll. Dubbed “chlorophyll f”, this new chlorophyll was discovered in cyanobacteria inside stromatolites and can absorb light wavelengths more than 700 nanometres (in the near-infrared region of the electromagnetic spectrum).

This discovery might have implications for future energy generation technologies, and even the odds of life on other planets, but perhaps more importantly it is a reminder that we stil have a lot to learn about the world around us – even the really old bits.