||John A. Raven Functional evolution of photochemical energy transformations in oxygen-producing organisms, Functional Plant Biology, 2009, 36, 505–515 p.505 left column bottom paragraph
||Raven JA (2009) Contributions of anoxygenic and oxygenic phototrophy and chemolithotrophy to carbon and oxygen fluxes in aquatic environments. Aquatic Microbial Ecology, in press.
||Anoxygenic photosynthesis only accounts for ~0.1% of aquatic
primary productivity, and 0.05% of total primary productivity,
on Earth today (Raven 2009). See BNID 105040