COULD PHOTOSYNTHETIC EUKARYOTES HAVE SURVIVED IN NEARLY ENCLOSED SEAS DURING THE SNOWBALL EARTH EVENTS?

During the global glaciations of the Cryogenian, the Earth’s oceans may have been completely covered with ice. If thick ice globally covered the oceans, consistent with a “hard snowball” interpretation, then where photosynthetic eukaryotic organisms may have survived during global glaciations of the Cyrogenian remains unclear. Our research tests weather a narrow arm of the ocean, analogous to the modern Red Sea, could have been a refugium for photosynthetic eukaryotes during Snowball Earth events. We demonstrate that for a limited range of climate conditions, ice flow into an arm of the sea is restricted sufficiently to allow for the sea to remain partially free from sea-glacier penetration, a necessary condition for it to act as a refugium for photosynthetic eukaryotes during a Snowball Earth event. The range of possible climate conditions that allow for these nearly enclosed sea act as refugia for photosynthetic eukaryotes during is increased by considering the effect of a narrow entrance to the channel and the formation of ice shadows on the leeward side of obstacles within the channel.