Top 20 Amazing Ocean Mysteries and Phenomena

The oceans contain great mysteries within their depths. While many of these mysteries have been explained by scientists and analysts, quite a few unexplained oceanic enigmas still intrigue us.

A variety of mysterious ocean phenomena have also been seen and experienced by sailors around the world.

Some such oceanic enigmas – both solved and unsolved – that have been popular topics of verbal analysis can be itemised as follows:

1. Milky Sea Phenomenon

The Milky Sea refers to the unique milky glow of the Indian Ocean waters. This ocean phenomenon occurs due to bioluminescent bacteria which turns it blue. It appears to the naked eye as milky white in the dark. The Milky Sea phenomenon has been documented to have existed for over four centuries.

2. Bioluminescence

Bioluminescence is the light produced by marine creatures as a defence mechanism. When counteracted with atmospheric oxygen, certain chemicals in the creatures’ bodies result in the emergence of bioluminescent light. Know more about the Bioluminescence Ocean mystery here. 

3. Convergence of Baltic and North Seas

This oceanic phenomenon has been a highly debated topic. The convergent point of the North and the Baltic Seas occurs in the province of Skagen in Denmark. However, because of the differing rates of densities of the seas’ waters, the sea waters continue to remain separate despite their convergence. It is said that this ocean phenomenon is mentioned in the holy Quran.

4. Steaming Black Sea

Called the ‘sea smoke’, the steam arising out of the Black Sea is caused by the humidity of the oceanic water counteracting the coolness of the wind over the water’s surface. Apart from explaining the ocean mystery behind the steam rising from the Black Sea, experts have also proved that the phenomenon is quite common to smaller water bodies.

5. Green Flash

The ocean phenomenon of green flashes occurs during sunset and sunrise. Usually seen for merely a few seconds, such green flashes result from the natural prismatic effect of the earth’s atmosphere. During sunset and sunrise, the light cast by the sun gets diverged into multiple colours, which is seen by the emitting of the green flash.

6. Baltic Sea Anomaly

The Baltic Sea Anomaly was accidentally discovered by a team of diving experts in the year 2011. The divers found a 60-metre thick circular entity nearly at a depth of 90 metres in the Baltic Sea.

A track seemed to lead towards the entity, which the divers measured to be around 300 metres. Though various scientists have offered innumerable suggestions about the entity’s origins, the Baltic Sea anomaly remains one of the world’s unsolved intrigues and ocean mysteries. Learn more about the Baltic Sea Mystery here. 

7. Brinicle

Concentrated salt water escapes from within the ice formed above the ocean’s surface and seeps into the depths of the water. However, once the concentrated salt goes under the water’s surface, on account of natural processes, it freezes and forms into brinicles. Brinicles occur in the frigid oceanic waters around the poles.

8. Red Tide

The occurrence of red tide is technically called ‘Algal Blooming’ by scientists. The ocean phenomenon occurs when there is rapid growth or blooming of algae in the oceanic waters. The presence of red tide is highly dangerous as these algae can be fatal to birds, animals and even humans.

9. Sea Foam

The foaming of the seas is caused by the disturbance to the organisms present on the water surface due to the constant tidal action. Alternatively, in certain cases, seafoam can also be caused by disturbances caused by human activities like the dispelling of waste toxicants into the oceanic water.

10. Underwater Crop Circle

Once regarded to be objects of high intrigue, the underwater crop circles have been explained to be a creative demonstration of pufferfishes’ quests to find their mates. These underwater circles have circumferences of over six feet and are often decorated with shells and other decorative items found at the bottom of the sea. The underwater crop circles were discovered under the waters of the Japanese island of Anami Oshima. Some consider these ocean mysteries as the work of aliens.

11. Mysterious Julia Sound:

Heard and recorded by the NOAA (National Oceanic and Atmospheric Administration), ‘Julia’ was the spooky sound heard over a 15-second duration in 1999. According to NOAA’s experts, the sound was said to have originated from the Pacific Ocean near the equator and ricocheted from an iceberg being grounded in the Antarctic.

12. Striped Icebergs

Icebergs break off from glaciers due to calving and the ice pieces come off in different sizes and forms, known as brash ice, bergy bits, tabular berg etc. Sometimes, icebergs come with coloured stripes – including brown, black, green, yellow, and blue- unlike the normal white pieces. Called striped icebergs, these chunks of ice acquire colours due to different reasons.

According to scientists, blue stripes are created when the ice melts and freezes quickly, without forming bubbles due to compression. Since the Iceberg’s absorption spectrum is similar to that of water, it absorbs all colours except blue. The iceberg gets a green colour due to the rich algae in the seawater. However, colours such as brown, yellow and black appear on an iceberg due to the sediment picked up from the ground before the large chunk of frozen water falls into the sea.

13. Maelstrom

Maelstrom, the powerful and dangerous whirlpool, is one of the seafarers’ biggest nightmares. Though whirlpools, a body of swirling water caused by a turbulent flow are common, Maelstrom is massive in size and force and could even put huge ships in danger.

Norway’s Saltstraumen is the deadliest maelstrom in the world due to its strongest tidal currents. Situated at a narrow strait near the town of Bodø, Saltstraumen features the passage of an estimated 400 million cubic meters of water through the Strait four times a day, reaching speeds of 40 km/h.

Moskstraumen is the second strongest Maelstrom in the world. Located in the open seas in the Lofoten Islands off the Norwegian coast, the circular currents of water in this deadly whirlpool reach speeds as high as 32 km/h. Another named Corryvreckan is the third largest whirlpool in the world. Located between the islands of Jura and Scarba, Corryvreckan produces currents that reach speeds of 18 km/h.

14. Frost Flowers

The flora and fauna in the sea comprise a variety of plants including marine algae and seagrasses, among others. However, the “frost flowers” that appear in the Arctic and Antarctic seas are a different phenomenon. The Frost flowers are not real flowers but are ice crystals that look like flowers.

The phenomenon happens when frost grows from imperfections in the surface ice, usually on young sea ice, during extreme sub-zero temperatures. The thin layers of ice come out from long-stemmed plants and are often shaped into patterns that resemble real flowers. Researchers have found that such flowers, apart from frozen water, contain a variety of microorganisms, acting as a temporary ecosystem.

15. Brazilian’s Longest Wave on the Earth

The Brazilian’s longest wave on the Earth, called the Pororoca, is a result of the tides of the Atlantic Ocean which meet the mouth of the Amazon River twice a year.

In the days between February and March, the waters of the Atlantic Ocean roll up the river in Brazil, producing waves that are wave two to three kilometres wide and capable of moving along at up to 30 kph.

Reports suggest that the phenomena occur once a night and once a day for three days between February and March.

The name “Pororoca” derives from the indigenous Tupi language, in which locals consider it a “great roar” due to its destructive nature. The wave, which can be heard about 30 minutes before its arrival, destroys everything on its way.

16. Submarine volcano

According to reports, the ocean experiences the most productive volcanic systems on Earth, mostly under an average of 8,500 feet (2,600 m) of the surface. An estimated 75% annual output of magma is produced through these underwater vents or fissures in the seabed.

While most active submarine volcanos are situated in deep water, there are few in shallow water, often disclosing their presence by discharging materials high above the surface. Scientists suggest that there are more than 1 million submarine volcanoes and among these, few even rise over 1 km above the seabed during the eruption.

17. The Southern Cross

The Southern Cross, a popular star pattern in the southern hemisphere, has been credited for helping marine travellers find their way in the past. With its two-pointers, the asterism has been used as a navigational tool to find the South Pole.

The Southern Cross, one of the easiest asterisms to identify in the sky, forms part of the constellation Crux. According to scientists and astronomers, the stars that make up the Southern Cross include Alpha, Beta, Delta, Gamma and Epsilon Crucis. Among these stars, which are at least 10 to 20 million years old, the nearest is 88 light-years from the Earth, while the furthest is 364 light-years away from our planet.

18. Fata Morgana

A Fata Morgana is an optical phenomenon that creates a mirage which appears periodically above the ocean horizon. The Fata Morgana mirages distort the object on which they are based, sometimes making it fully unrecognizable. The term was coined in Italian, in which ‘fata’ means ‘fairy’ and Morgana stands for the sorceress from the legend of King Arthur. The name comes from a belief that those mirages or fairy castles were created by witchcraft to lure sailors to their deaths.

Fata Morgana happens, in scientific terms, when the light passes through air layers of different temperatures. Scientists suggest that the phenomenon occurs when a layer of warmer air comes directly above a cold air layer. Fata Morgana often hides a distant object, including boats, from the view.

19. Tidal Bores

Tidal bores, a popular tidal effect, happen when rising water from the ocean creates tidal waves that travel up rivers. The phenomenon usually occurs when a river empties into the sea and the tide pushes up the river water against the current.

The height of the bore will be greater near the banks of a river than at midstream. Tidal bores occur in areas where the river is fairly shallow and has a narrow outlet to the sea.

The great examples of tidal bores are those that occur on the Amazon and the Qiantang River in Southeast China. The tidal bore in Qiantang River, which is the world’s largest tidal bore, has heights of around 9 meters and can move as fast as 40 km per hour. Other popular tidal bores around the world are witnessed on the Seine River in France, the Severn in England, and the Petitcodiac River in Canada.

20. Moskenstraumen

Moskenstraumen is a tidewater whirlpool of the Norwegian Sea in northern Norway. Situated between the islands of Moskenesøya and Mosken, Moskenstraumen is one of the strongest tide water whirlpools in the world and forms due to a combination of several factors, such as tides, strong local winds, the position of the Lofoten and also the underwater topography.

It features strong tidal currents that flow between these islands and later the Atlantic Ocean and the deep Vestfjorden.

Unlike other whirlpools, Moskenstraumen takes place in the open sea and the current measures around 8 km in width and sometimes reaches 11 km per hour. According to reports, the flow of currents is strongest in July and August.

Over to you…

Do you know any other ocean mystery or phenomena that should be listed here?

Let us know in the comments below.

You may also like to read –

• Understanding Thermoclines In Ocean Waters
• What Are Tide Pools?
• What is a Mid Ocean Ridge?
• The South Atlantic Anomaly: Understanding the SAA Phenomenon

References: bbc, wikipedia, howstuffworks, inhabitat

Image Credits: dianevarner, postimg, islandpartnershawaii, bobbiblogger, huffpost, coolinterestingstuff, inhabitat

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About Author

Raunek Kantharia is a marine engineer turned maritime writer and entrepreneur. After a brief stint at the sea, he founded Marine Insight in 2010. Apart from managing Marine Insight, he also writes for a number of maritime magazines and websites.

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