Water is exchanged at the slowest of rates making the med as clear as a swarovski crystal. Limited water exchange = limited food for tiny organisms called phytoplankton aka algae, and it's these little dudes who play the lead role in water clarity. The Mediterranean is classified as “oligotrophic”.
Are Mediterranean cruises bumpy?
The Mediterranean Sea Can Be Surprisingly Choppy Year RoundRough Waters: Cruise travelers might experience rough seas in several places in Europe. The biggest offender is the Mediterranean, which tends to be roughest in the fall and winter, due to winds and storms.