Could narrow marine embayments prevent sea-glacier invasion, and protect photosynthetic life during a Snowball Earth?

Abstract

During the Snowball Earth events of the Neoproterozoic, the Earth’s oceans may have been completely covered in ice. This ice would have been thick enough to prohibit the transmission of light to the liquid water underneath the entirely frozen surface of the ocean. However, photosynthetic eukaryotes are thought to have survived during these events. This is the first work to throughly attempt to reconcile how photosynthetic eukaryotes survived on a planet with a completely frozen ocean surface. Narrow marine embayments like the modern-day Red Sea, would restrict the inflow of sea glaciers. These embayments, if located in regions of net sublimation, would restrict sea-glacier invasion and could provide refuge for these organisms at the end of their channels. This work demonstrates that under a set of climate conditions and channel geometries, narrow marine embayments allow for incomplete sea-glacier invasion, a necessary condition for marine embayments to provide refugia