Undersea Geography Trivia Quiz

Answer: Pharos of Alexandria

The Pharos (or Lighthouse) of Alexandria was built in the third century BCE in northern Egypt to help guide ships to safe harborage. Estimated to have been around 400 ft (122 m) tall when in use, it was one of the world's largest constructs for centuries.

The lighthouse was damaged by several earthquakes over the course of the centuries and is believed to have collapsed in the 1300s; a fortress was built in its place in 1480. Physical evidence of the lighthouse's existence was lacking until 1994 when some of its remains were discovered in Alexandria's harbor.

Answer: Vanuatu

Vanuatu Post's Underwater Post Office is situated around 164 ft (50m) and 10 ft (3 m) below the shore of Porta Vila, the capital of Vanuatu. It is a popular tourist destination for divers and accepts waterproof postcards that can be purchased in the settlements of Vanuatu.

This branch of the Vanuatu Post has been in operation since 2003 and is usually open for about an hour per day. Two stamps have been issued in commemoration of this underwater post office.

Answer: volcano

Tamu Massif is an extinct shield volcano formed during the Jurassic/Cretaceous period about 145 million years ago. To call it large may be an understatement: it is about the size of Britain and Ireland combined! Tamu Massif was confirmed as a single volcano in 2013 and is the largest volcano known to exist on Earth; it is located in the northwestern Pacific Ocean due east of Japan.

Answer: mausoleum

Neptune Memorial Reef is an artificial reef that also serves as a mausoleum. It was created off the coast of Miami, Florida, and is replete with roads, benches, statues, and graves. The reef contains the remains of cremated people; these are mixed with cement to create stones, which are added to the site. People who choose Neptune Memorial Reef as their final resting place may do so to get a green burial at sea, rather than a more traditional land burial.

Answer: volcanic eruption

Krakatoa is a volcanic island, one of the many islands of Indonesia. In 1883, following seismic and volcanic activity, the volcano on the island erupted in what became one of the most destructive volcanic explosion in history. The blast was heard as far away as Australia, and caused a large part of the island to sink under the sea.

A new island emerged at the site of the volcano and is called Anak Krakatau; naturally, it is the center of more volcanic activity.

Answer: Christ of the Abyss

Guido Galletti created an 8 ft (2.5 m) tall bronze statue of Jesus Christ, with his arms outstretched as if offering a benediction. The statue was submerged off the coast of the Italian Riviera in 1954. In 2003, the statue was temporarily removed from its location to restore damage and corrosion that had accumulated over the decades. Several copies of the original exist worldwide.

Answer: underwater desert

Underwater deserts most commonly occur beneath large gyres (systems of circular currents). In such places, nutrients are prevented from reaching the ocean's surface, usually by strong currents. The lack of essential nutrients limits the growth of algae in the sunlit surface zone; this in turn starves any animals that feed on algae (whether directly or indirectly). As a result, the food web of such a place starves and ceases to exist.

One of the the most notorious underwater deserts can be found below the North Pacific Gyre. Estimated to be the size of Texas, a pile of non-biodegradable trash has accumulated above this region, and contributes to the lack of nutrients in the area and starvation of the local ecosystem.

Answer: Yes

On land, hydrothermal vents include the likes of hot springs and geysers. While not quite the same, vents ejecting hot water can be found in many places under the sea. Such vents are commonly found near hotspots or volcanically active places. Hydrothermal vents support unique types of lifeforms, providing heat and nutrients to chemosynthetic (as opposed to photosynthetic) bacteria.

These in turn provide a basis for an ecosystem which includes larger animals, like tube worms, lobsters, and clams.

Answer: Port Royal, Jamaica

Port Royal was founded in Jamaica in 1518, and for about two centuries was notorious for its privateers, riches, and wanton morals. It was built quickly, and became what people now think of as a stereotypical pirate haven. It wasn't built to last though: in 1692, an earthquake hit Port Royal, liquifying its marshy ground.

In a matter of minutes, two-thirds of the city sank under the sea, and about half its population was killed. Hurricanes, fire, and another earthquake devastated the remnants of the city in the centuries that followed. Today, Port Royal is a minor city occupying the area of the historic Port Royal, with little political or economic influence.

Answer: Venice

Venice is a beautiful city in northeastern Italy, famous for its canals and gondolas. Though the waterways make for a scenic setting, they belie the fact that Venice is sinking into the sea. Venice was built on wooden piles around sea level, and tides from the Adriatic Sea (known as acqua alta) flood it on a weekly basis. Wells drilled in the 20th century drew water from the aquifer below the city, causing sinking and increasing the effect of the acqua alta. Though wells no longer draw water, the tides flood the ground floors of many buildings and render them uninhabitable.