Ancient humans from Asia may have entered the Americas following an ocean highway made of dense kelp.
I wish there were still highways of kelp. The best we get these days is kelp forests. Which are pretty awesome. Giant kelp (genus Macrocystis) can grow 30-60 centimeters a day! For you Americans, that is 1 or 2 feet! I am imagining a highway of dense kelp. It is very slippery. In elementary school we studied kelp a lot. This is because Palo Alto is very close to the Pacific Coast, where some of the largest Giant kelp forests grow. We dissected giant kelp pneumatocysts. Pneumatocysts look like ovoid air bubbles made out of seaweed. They are like blimps attached to the kelp so that it can stay upright and not flop over. One of the reasons it needs to stay upright is so that its blades (strong, broad, long leaves) can be exposed to the sun and photosynthesize enough to support such a crazy growth pattern. Kelp forests are also very interesting because they represent an incredibly lush ecosystem. I love kelp.