Opponents have voiced their concerns about Mose's impact on the lagoon's ecological systems, as holding back water in this way could lead to depleted oxygen levels.
Since these dense lower waters don't mix with the warmer freshwater above, it can take four months for tropical storms to fully circulate oxygenated water back into the gulf.
In particular, it's been hypothesized that an ice dam holding back water from a gigantic lake in North America melted, sending huge amounts of freshwater into the Atlantic Ocean.