Strait of Gibraltar
The Strait between Atlantic Ocean and Mediterranean Sea
The Strait of Gibraltar connects the Atlantic Ocean and the Mediterranean Sea, is about 60 kilometres long and between 14 and 44 kilometres broad. The Strait of Gibraltar is the only natural link between the Atlantic Ocean and the Mediterranean Sea and is one of the busiest waterways in the world. Approximately 300 ships cross the Strait every day, about one ship every 5 minutes. Due to the special currents there is also a good supply of food here, which even attracts whales and dolphins. During whale-watching tours with firmm you can observe these fascinating marine mammals.
The narrowest point of the Strait is just off Tarifa: from the southernmost city of mainland Europe it is only 14 kilometres to Mount Jbel Musa in Morocco/Africa. This is why many migratory birds cross the Strait here on their routes between Europe and Africa.
A look back to primeval times
(Roger Pibernat under supervision of Daniel Garcia-Castellanos)
Today's Mediterranean basin is a remnant of the Tethys Sea, which existed around the time of the dinosaurs. When the African and Indian plate collided with the Eurasian plate, the Tethys Sea gradually disappeared. A land bridge was built, which completely separated the Mediterranean Sea from the ocean about 6 million years ago. Without this connection, the Mediterranean Sea dried out into a huge salt desert.
About 6 million years ago, the Mediterranean Sea dried up.
The land bridge sank slightly about 5.3 million years ago, allowing water to flow back into the Mediterranean basin. For several millennia this was only a small amount. But the water dug deeper and deeper into the land bridge and with time ever larger water masses flowed in, until the water level in the Mediterranean rose at the end probably up to 10 meters per day.
The Strait of Gibraltar today
Because more water still evaporates than is brought in by rivers and precipitation, the Mediterranean would today dry out again without the connection to the Atlantic. The water level of the Atlantic Ocean is about 1.5 meters higher, so that about 1 million cubic meters of water per second flow into the Mediterranean Sea at the surface.
Due to its high salt concentration, the Mediterranean water is considerably heavier and therefore sinks down over the deeper Mediterranean basin, pushing deep water back into the Atlantic. In the elevations and depressions of the Gibraltar sill in the area of the Strait, turbulences occur, which bring many nutrients from the depths to the surface.
Nutrient-rich water together with light supports the formation of plant plankton (phytoplankton) - a prerequisite for the large food supply. Whales and dolphins also benefit from this. So it is not surprising that we can regularly observe seven species of whales and dolphins in the Srait, despite the heavy traffic.
Speed limit for the Strait of Gibraltar
To protect whales, the Spanish Ministry of Environment set a speed limit of 13 knots (24 km/h) for the Strait in February 2007. firmm was not insignificantly involved in the decision: Our years of research and efforts had contributed to the fact that this topic was discussed at all.
The Strait in Mythology
The Rock of Gibraltar and Mount Jbel Musa in Morocco are also known as the Pillars of Hercules. According to Greek mythology, Hercules was supposed to cross Mount Atlas to rob the herd of cattle from the giant Geryon. But with his superhuman strength he smashed through the middle of the mountain and thus created the Strait of Gibraltar. At the end of the Mediterranean, he marked the end of the world with the inscription "non plus ultra" (not beyond).
The Pillars of Hercules including inscription found their way into the Spanish coat of arms under Carlos I (also German Emperor Charles V). However, since America had already been discovered, the motto was changed to PLUS ULTRA (beyond that). Columns and inscription also decorate by the way today's national coat of arms of Spain.