The effects of mountain belts in supporting the conditions for the development of complex life forms in adjacent basins are warmly debated today. In this paper, MOBILE Project researchers show that, while mountains might provide oxygen and nutrients, if a sea basin becomes surrounded by mountains and completely restricted, this effect might become damaging to complex life. This is due to eutrophication, a phenomenon that occurs when an overburden of nutrients causes algal blooms that block the sunlight and consume all of the basin’s oxygen, restricting the conditions for complex, oxygen-dependant organisms. This effect is, thus, one of optimal conditions, or “Goldilocks”-type. Besides, restricted basins under anoxic conditions might have contributed with vast amounts of greenhouse gases such as methane, which might have caused the planet to overheat various times during it’s history. In the neoproterozoic-cambrian fan-like transition from Rodinia to Gondwana, while the newborn coasts of Laurentia, Baltica and Siberia remained open to the global sea, marginal basins of Gondwana were progressively landlocked. The extent to which those restricted basins damaged ediacaran-cambrian ecosystems and contributed to Earth’s climate needs to be further considered.
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