Recent research reveals that the Marinoan Ice Age, once thought to be a complete freeze of the Earth, may have actually been a “Slushball Earth.” This perspective comes from geologic samples and ancient algae, dating back over 600 million years, suggesting patches of open water in shallow mid-latitude seas allowed life to persist. Scientists previously labeled this ice age, which occurred 635 million years ago and lasted 15 million years, as “Snowball Earth,” believing the planet had experienced total glaciation. However, the new study indicates the presence of habitable marine environments, primarily in shallower regions where conditions for photosynthetic macroalgae existed.
Researchers found evidence that these open waters could have facilitated survival for both single-celled and multi-celled organisms. They propose a dynamic climate during the ice age, with intervals of freezing and melting. Interestingly, the algae may have contributed to the ice age’s end by releasing carbon dioxide into the atmosphere, warming the planet. This study prompts reevaluation of other ice ages and underscores the significant role of the biosphere in influencing the carbon cycle and global climate. The findings were published in Nature Communications.
