When did oxygenic photosynthesis evolve?

Abstract

The atmosphere has apparently been oxygenated since the 'Great Oxidation Event' ca 2.4 Ga ago, but when the photosynthetic oxygen production began is debatable. However, geological and geochemical evidence from older sedimentary rocks indicates that oxygenic photosynthesis evolved well before this oxygenation event. Fluid-inclusion oils in ca 2.45 Ga sandstones contain hydrocarbon biomarkers evidently sourced from similarly ancient kerogen, preserved without subsequent contamination, and derived from organisms producing and requiring molecular oxygen. Mo and Re abundances and sulphur isotope systematics of slightly older (2.5 Ga) kerogenous shales record a transient pulse of atmospheric oxygen. As early as ca 2.7 Ga, stromatolites and biomarkers from evaporative lake sediments deficient in exogenous reducing power strongly imply that oxygenproducing cyanobacteria had already evolved. Even at ca 3.2 Ga, thick and widespread kerogenous shales are consistent with aerobic photoautrophic marine plankton, and U-Pb data from ca 3.8 Ga metasediments suggest that this metabolism could have arisen by the start of the geological record. Hence, the hypothesis that oxygenic photosynthesis evolved well before the atmosphere became permanently oxygenated seems well supported.

The evolution of Earth's biogeochemical nitrogen cycle

“…We note that the time constraints used to calculate when this transition occurred (Boyd et al, 2011a) are extremely conservative, in particular the placement of oxygenic photosynthesis at 2.5 Gyr. As there is now abundant evidence for the evolution of oxygenic photosynthesis well before this late date, perhaps even as early as 3.8 Gyr (Buick, 2008;Rosing and Frei, 2004), a revised calculation should yield molecular clock ages more compatible with the isotopic data. Secondly, increasing evidence for an origin of the nitrogenase enzyme in thermophilic methanogenic Archaea -perhaps the most ancient phylum on Earth - (Boyd et al, 2011a;Mehta and Baross, 2006;Nishizawa et al, 2014;Raymond et al, 2004) may suggest that nitrogenase is ancient and predates the radiation of cyanobacteria.…”

“…Constraining the history of oxygen production and accumulation in surface environments is thus required to arrive at accurate reconstructions of nitrogen speciation and bioavailability through time. The oldest possible signs of oxygenic photosynthesis date back to 3.8 Gyr (reviewed in Buick, 2008). Recent work proposes a minimum age of 3.0 Gyr (Crowe et al, 2013;Planavsky et al, 2014a).…”

Iron formations: A global record of Neoarchaean to Palaeoproterozoic environmental history

“…Olson et al (2013) estimated that photic zone O 2 contents could be as (6) Several weight percent concentrations of organic carbon in sedimentary rocks provide one of the most straightforward and compelling arguments for the Archaean evolution of oxygenic photosynthesis, although this record becomes sparse for strata older than ~2.8 Ga. A wide range of microbial metabolisms can, of course, generate organic carbon, but only a handful of these metabolisms can realistically produce organic carbon-rich sedimentary rocks (Buick, 2008;Lyons et al, 2014;Krissansen-Totton et al, 2015). Since photoferrotrophy produces a particulate Fe(III)-oxyhydroxide as well as organic carbon, this process is more likely, as outlined below, to produce organic carbon-poor, iron-rich rocks like IF, because much of the organic matter would be oxidised via DIR, which, if this process was widespread, would limit the use of organic carbon content in IFs as a direct indicator of organic carbon deposition.…”

A multidisciplinary reconstruction of Palaeolithic nutrition that holds promise for the prevention and treatment of diseases of civilisation

“…natural selection and the conditions of existence, where the latter was considered the most powerful (2) . For example, important steps in evolution are the origin of eukaryotic life approximately 1·6 -2·7 billion years ago (3,4) and the appearance of photosynthetic cyanobacteria that began to oxygenate the atmosphere about 2400 million years ago (Mya) (5) . However, there was relatively little alteration in the design of life forms before the Cambrian explosion about 600 Mya.…”