"In fact we've all experienced modern bacteria feeding in this way as that's where that ‘rotten egg' whiff of hydrogen sulfide comes from in a blocked drain. So, rather surprisingly, we can say that life on earth 1,900 million years ago would have smelled a lot like rotten eggs,' said Martin Brasier of Oxford University's Department of Earth Sciences, an author of the study published in this week's Proceedings of the National Academy of Sciences (PNAS).
‘Whilst there is chemical evidence suggesting that this mode of feeding dates back 3,500 million years, in this study for the first time we identify how it was happening and ‘who was eating who,' Brasier added.
Whereas plants and some bacteria that are autotrophs can obtain their energy from sunlight, heterotrophs must obtain their energy from the food they eat.
‘What we call ‘heterotrophy' is the same thing we do after dinner as the bacteria in our gut break down organic matter,' Brasier said.
Only 1,900 million years ago the favorite dish was Gunflintia, for breakfast, lunch, and dinner.