Earth can’t be a closed system, otherwise the heat from the Sun would slowly build up until it would be unbearable. There are two physical possibilities of ventilation: 1. The holes near the poles. If they exist, then obviously water and air comes in through the south pole hole and exits the northern one. These would conduct and convect the Sun’s heat out of the Earth.
(Click to animate). The north pole hole sucking in air and water?
2. The Earth’s crust could be quite porous. There are lots of known and unknown cave systems in the world, some of which have been nowhere near fully explored, i.e. nobody knows how far back they go. E.g. Mammoth Cave in Kentucky USA and has 400 miles (640 km) of surveyed passageways. If these caves exist in the ground above sea level, they are bound to also exist below sea level in the lakes, seas and oceans. Wind cave in western South Dakota has breezes which “can be strong enough to visibly stir nearby plants”. Maybe this windy cave is connected to the “outside” like the one from the Macuxi tribe tale.
3. There is a third possibility, but this is more in the realms of fringe science – other world portals, and/or vortices. There are stories of “cold spots” and “gravity anomalies” in certain areas that can’t be reasonably explained, such as the Oregon vortex.
Physical “impossibilities” exist in certain areas.
Vortices and other-world portals are associated heavily with US national parks (missing 411), the underworld stories, from ancient to modern, and haunted locations. Do they exist? Maybe. It would at least offer another possibility that in a few areas physical properties (such as heat) can be transferred inter-dimensionally.