(PhysOrg.com) -- Toxic seas may have been responsible for
delaying the evolution of life on Earth by 1 billion years,
experts at Newcastle University have revealed. The study,
published online today in Nature Geoscience, reveals for the
first time a chemical ‘layering’ of the ocean which may have
delayed the evolution of our earliest animal ancestors. Using
novel geochemical techniques developed by Newcastle University’s
Dr Simon Poulton, the team found that beneath oxygenated surface
waters, mid-depth oceanic waters were rich in sulphide about 1.8
billion years ago, conditions that may have persisted until
oxygenation of the deep ocean more than1 billion years later.
These widespread sulphidic conditions close to the continents,
coupled with deeper waters that remained oxygen-free and iron-
rich, would have placed major restrictions on both the timing
and pace of biological evolution. Dr Poulton, who led the
research, explained: “It has traditionally been assumed that the
first rise in atmospheric oxygen even