500 scientists have counted in a census 235 species of both the Arctic and the Antarctic. This research was conducted within the framework of the Marine Life Census, International Polar Year --i.e. 2007-2008 - and will be published in 2010.
They found the same worms and molluscs that live in the barros, about 12,000 kilometers. In icy Arctic and Antarctic waters, molluscs of Cliona limacina and Limacina helicina were detected. The researchers were surprised that it is common for birds and whales to migrate from one pole to another, but not that small molluscs migrate so much.
However, researchers at the Marine Life Census claim that 12,000 kilometers are not a major obstacle. And they consider that the temperature change is also not a barrier: the temperature in the deep waters of the poles is -1 °C and that of the tropics does not pass by 4 °C. In addition, the surveyed scientist Ron O'Dor has stated that current systems generate continuity in the oceans. This perseverance is called the ocean conveyor belt. According to the researcher, many of the beings present at the two poles can transport their larvae and eggs in these waters.