Ancient Underwater Worlds

"Discover what the marine world was like in the prehistoric Mesozoic and the Cenozoic era. Let’s also explore the finds of underwater cities!"

Have you ever wondered about the Legend of Atlantis and if it was real? You can find accounts of the Atlantean civilization in the famous works of the Greek philosopher Plato. But so far, there hasn’t been any evidence of this great and mighty underwater continent. 

Now, don’t you get disappointed, as there are other underwater worlds that we have plenty of evidence to believe they are real! This article will explore how the oceans have evolved from the Mesozoic era to the ancient submerged underwater worlds.

Ancient Underwater Worlds

Marine World in the Mesozoic Era

The Mesozoic era spanned about 186 million years and is divided into three periods: Triassic, Jurassic, and Cretaceous. At the beginning of this era, the continents were joined together into one called the Pangea. During the time of the dinosaurs, it split into two continents: Laurasia and Gondwana. Laurasia split into North America and Eurasia, and Gondwana transformed into South America, Australia, Africa, Antarctica, and the Indian subcontinent. In this era, it was usually warm, and there were no ice caps, resulting in rising water levels after the Triassic period.

During the Triassic period, the marine reptiles dominated the oceans, and many of them were like large scaly newts. They predated on the bivalves, squids, fish, cephalopods, and each other. Some popular reptiles were ichthyosaurs, sea turtles, plesiosaurs, and mosasaurs. The planktons evolved during the Mesozoic era. Coccolithophorids were microscopic planktons and were abundantly found during the Cretaceous period. When planktons die, they form chalk and limestone on the seafloor. 

The popular White Cliffs in Dover, England, are a testimony to trillions of these Cretaceous planktons. The dead planktons also form oil when they accumulate on the seafloor for millions of years. At the beginning of the Mesozoic era, the Permian extinction event destroyed almost all the ocean’s reefs. It took millions of years of evolution for new and diverse ecosystems to evolve. Bivalve mollusks like ‘rudist clams’ built most of the reefs during the time of dinosaurs.

Finally, the Cretaceous period saw the end of this era’s ecosystems due to the K/Pg extinction event. Around 66-million years ago, a 6-mile-wide asteroid hit the Earth’s surface, causing the extinction of many species around the planet. However, this catastrophe resulted in new lineages of life emerging, like the present-day whales, manatees, and seals.

Ancient Underwater Worlds

Marine World in the Cenozoic Era

The K/Pg extinction resulted in a new era called the Cenozoic, which runs until today. At the beginning of this era, the ocean basins and continents were similar to what we have today, and the movement of the tectonic plates caused the continents to shift. During this period, around 34 million years ago, South America and Australia broke apart due to the movement of the plates and plunging temperatures. The tectonic collisions caused mountains to form. Some parts of the world, especially the Northern Hemisphere, witnessed lower temperatures causing the formation of the continental ice sheets. 

The sea levels gradually dropped, leading to the closure of some seaways and the formation of land bridges like Panama. The Caribbean was gradually separated from the nutrient-rich waters of the Pacific, due to which the Caribbean marine life needed to adapt. New species began to form, like the Pacific goliath grouper and the Atlantic goliath grouper. It also resulted in diverse algae and corals in the Caribbean.

This period also saw the emergence of new giant aquatic mammals like blue whales, which gradually evolved to have huge bodies. While the baleen whales consumed crustaceans, another aquatic mammal, Desmostylia, grazed on seagrass and kelp. These marine mammals also lived on land like the seals and sea lions, but they had feet instead of flippers. They existed in the Oligocene to late Miocene and are now completely extinct. 

Steller’s sea cows were massive ocean creatures and relatives of dugongs and manatees. They fed on kelp like the sea urchins. Sea otters were primary consumers of sea urchins, whose population exploded due to the humans hunting the sea otters for pelts. As a result, the Steller’s Sea cows are now extinct because the urchins consumed the kelp forests. Other sea animals lost due to human exploitation are the flightless auks, Caribbean monk seal, and the Japanese sea lion.  

Now, let’s look at some famous sunken civilizations and structures of ancient times found in the present-day waters.

Ancient Underwater Worlds

Ancient Underwater Worlds

The City of Thonis-Heracleion (Mediterranean)

Thonis-Heracleion was founded in the eighth century BC. The ships entered Egypt from Greece via its port, and it’s also an important city because of the temple of Amun. It sank into the Mediterranean Ocean in the eighth century AD due to catastrophic events. Its underwater ruins were first discovered in 2000 by the IEASM (The European Institute for Underwater Archaeology). Before its discovery, there were only written records of this lost city, as you can find in the works of the Greek historian Herodotus. You can see various objects of this ancient city in the excavations like coins, jewelry, ceramics, statues, etc.

Yonaguni Jima (Japan)

Yonaguni Jima is an island in western Japan nicknamed Japan’s Atlantis. In 1987, a local diver was exploring the Ryuku Islands and stumbled upon an underwater pyramid-like structure. It’s now known as the Yonaguni Monument, and researchers believe it’s over 10,000 years old. There’s still dispute on whether this monument is man-made or natural. We might not know its origin yet, but it’s been a source of wonder and fascination for history buffs and travelers alike.

Baia (Gulf of Naples)

Baia was a town in Rome between 100 BC and 500 AD that sank underwater due to volcanic activity. The residents got a chance to flee the town while the water levels were rising before it submerged under the Gulf of Naples. This city was famous as a playground for the rich. The famous Julius Caesar also had a villa there. Some people rightly call Baia “the Las Vegas of the Roman Empire.” The seabed of its ruins is now scattered with its sculptures, some headless. You can also find the city’s statues, columns, and frescoes.

Pavlopetri (Greece)

Pavlopetri is the oldest known city submerged underwater. Researchers believe it was last intact on land in 1000 BC. when it sank following an earthquake. A marine biologist from the University of Southampton, Nicholas Flemming, discovered it in 1967 while diving in Laconia’s Vatika Bay. Upon investigation of the site, Flemming, with his fellow students, found a grid of streets, stone houses, gardens and courtyards, graves, and pottery shards from the Mycenaean period. Later studies revealed that the city was older and larger than it first appeared and had temples, well-designed road and water systems, and a big plaza.

Atlit Yam (Israel)

Atlit Yam was a Neolithic village located off the coast of the town of Atlit, Israel. It’s one of the earliest sunken places found underwater, dating around 7000 BC. Its remnants were discovered in 1984 under the Mediterranean Sea, like the stone wells, graves with skeletons, and grain stores. You can also see a mysterious stone circle, with seven megaliths, in ruins.

Ancient Underwater Worlds

Ekta G

Ekta G


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