Mysterious line found in ocean that some jellyfish won't cross
A mysterious 'semi-permeable faunal boundary' has been found in North Atlantic Drift dividing two forms of Botrynema brucei ellinorae jellyfish. Both are genetically similar, but one has a hood knob while other doesn't. Researchers say knob offers protection from predators, allowing them to move and survive in warmer southern waters, while knob-less ones stay restricted to colder Arctic regions.