The movement of a bottle thrown into the sea would be dictated by thermohaline circulation or the global conveyor belt. The nickname of the deep circulation pattern appeared due to the resemblance with a belt that girdles the Earth. The thermohaline circulation incorporates different water temperatures and depths. As a result, the global conveyor belt can carry surface water into the depths and back to the surface. If a bottle were sunk in the Northern Atlantic Ocean, it would flow along with the water mass through the Atlantic. Further, the bottle would flow over deep-water formations near Antarctica. Then, it would be carried around Antarctica and move with the water to the north. The bottle would then travel into the Indian and Pacific Ocean basins.
The return of the bottle to the surface would be possible due to the diffuse upwelling in the ocean. Further, because of the surface circulation, water in the conveyor belt would warm progressively and mix upward. As a result, it would return to the North Atlantic by surface circulation. The significance of this slow-proceeding system is reflected in its ability to transport heat and water. It is possible to see the bottle surface at upwelling points. These points appear when circulating winds push surface water outward. Water in the upwelling may be moved horizontally about 100 kilometers or vertically about 100 meters. The cyclone affects the water underneath it as a result of what a current loop is formed. This loop has the shape of a “flattened donut.” On a global scale, the air is risen by equatorial heat. During this process, the air from farther south and north is pulled into the equator. Diverging waters cause the upwelling of deeper water near the equator, closer to the surface.
However, scientists admit that even though devices such as drift bottles can help trace surface currents, it is not possible to trace the path of such a bottle. Therefore, the mentioned path is only hypothetical. The bottle might travel through the global conveyor belt in accordance with the outlined direction only in case all processes in the atmospheric circulation are normal. If something abnormal happens, the suggested path cannot be applied.
What concerns the time it would take for a bottle to travel through the conveyer belt? Scientists are not optimistic, either. The reason for such a view is that the conveyor belt moves much slower than tidal or wind-driven currents. The movement of the belt is approximately a few centimeters per second. Therefore, it has been estimated by oceanographers that a cubic meter of water would take nearly 1,000 years to accomplish the journey along the global conveyor belt. What makes the mission even more complicated is that the conveyor moves a gigantic amount of water. The volume of water exceeds the flow of the Amazon River more than 100 times. Therefore, taking into consideration that a bottle takes up less volume than a cubic meter of water, it is possible to assume that it would be capable of traveling along the global conveyor belt in several hundred years.