From space, the famous Red Sea appears blue, which seems contradictory to its name. So why is it called the Red Sea?
The Red Sea looks like any other sea from space—dark blue. But why is it named the Red Sea? In fact, there are several explanations for this.
One possible explanation could be related to algae—in this case, the species Trichodesmium erythraeum. Sometimes called “sea sawdust,” this type of cyanobacteria (aquatic bacteria that survive through photosynthesis), belongs to the group of blue-green algae and is responsible for about 60%-80% of nitrogen conversion in the ocean, according to NASA’s Earth Observatory.
Why is the Red Sea called red?
T. erythraeum is prolific and found in most tropical and subtropical oceans worldwide. It grows abundantly in the Red Sea and is prone to periodic blooms. When these algae die off, the water can take on a reddish-brown hue as the dying algae spread across the sea’s surface.
However, it’s also possible that the Red Sea is named after the red mountains that line parts of its coastline, such as along the Jordanian coast. But the Red Sea is defined by more than just its name. It’s a biodiversity hotspot with many endemic animals found only in the Red Sea or the Gulf of Aden.
The Red Sea has one of the longest continuous coral reefs in the world. This reef stretches for 4,000 km and contains a rich diversity of marine life. The unique characteristics of the reef make it one of the rare marine refuges that allow many species to withstand climate change.
Corals that settled there at the end of the last ice age were the only creatures able to endure the very high temperatures and salinity of the Red Sea at that time. They adapted and now live in conditions that many other corals could not tolerate. Therefore, it is believed that they might be the last surviving corals in the world.