Fauna of Europe of the Baltic Sea has led to the evolution of many slightly divergent species, such as the Baltic Sea herring, which is a smaller variant of the Atlantic herring. The most frequent benthic species are "Saduria entomon" and "Monoporeia affinis", which is originally a freshwater species. A great part of its bottom is anoxic and without animal life. The Baltic Sea and North Sea are also home to a variety of marine mammals (common seals, grey seals). Europe contains several important freshwater ecoregions, including the heavily developed rivers of Europe, the rivers of Russia, which flow into the Arctic, Baltic,
Opening of the North Atlantic Ocean Opening of the North Atlantic Ocean The opening of the North Atlantic Ocean is a geological event that occurred over millions of years, during which the supercontinent Pangea broke up. As modern-day Europe (Eurasian plate) and North America (North American Plate) separated during the final breakup of Pangea in the early Cenozoic Era, they formed the North Atlantic Ocean. Geologists believe the breakup occurred either due to primary processes of the Iceland plume or secondary processes of lithospheric extension from plate tectonics. Rocks from the North Atlantic Igneous Province have been found in Greenland, the Irminger Basin, Faroe Islands, Vøring