In 1539, an extraordinary map was published by a Swedish priest – the Carta Marina - which showed the ocean as a place with an astonishing level of detail. The most notable features were large whorls east of Iceland, which might represent eddies at the Iceland-Faroe Front, an internal ocean boundary separating warm and cold water. Early mariners had to be very careful observers of the ocean environment. Read more here: http://www.po.gso.uri.edu/rafos/general/if_front/rossby_carta_2003.pdf #ocean #maps #history