Earth Science Researcher Leigh Anne Riedman Featured in The Current

This study combines sedimentology, geochemistry and paleontology of rocks 1.75 to 1.4 billion years old, showing that the oldest known eukaryotes (cells with nuclei and membrane-bound organelles) were benthic and already aerobic. This tells us about the origin and early evolution of eukaryotes, the group to which all animals, plants and morphologically complex life belongs. These data suggest that the acquisition of mitochondria had occurred by 1.75 billion years ago, and the complexity and diversity of the fossil assemblage points to a more ancient origin of eukaryotes than is typically appreciated. Additionally, we found that these organisms were restricted to the benthos, a finding consistent with hypotheses of bacterial and archaeal symbioses that lead to the formation of the eukaryotic cell. Further, restriction of eukaryotes to oxygenated benthic settings, a particularly narrow and ephemeral habitat for much of the Precambrian, might explain the puzzling delay in eukaryote diversification noted by several previous studies.

Link to The Current and Nature