A universe of beauty and charm. This is how we can describe our seas and oceans, home to the most varied forms of life. Today we already have greater knowledge about its extent and importance for the planet, but the marine surface remains harboring some mysteries that have not been fully deciphered.
One of them concerns the milky seas, a phenomenon that enchants travelers, sea lovers and scholars. The unmistakable shade of blue of the waters, which to the human eye is seen as a translucent white, has been observed for centuries. Over the period, many records were made by sailors, but only in recent years has it been possible to understand what it really is.
The bioluminescence present in the marine environment has been known for centuries, but still surprises observers today. (Source: Unsplash)
Reports throughout history
One of the most famous descriptions of the event was made by Charles Darwin, author of The Origin of Species , on his voyage to South America, which began in 1831. In the literature, similar reports were also present in Moby Dick (1851), by Herman Melville, and in the work Vint and A Thousand Leagues Under the Sea (1869), by Jules Verne .
And all these records were unanimous: it was not just any shine. For those at sea, the entire horizon lights up, making it impossible not to notice. The location of the occurrences varied, for example, on the island of Java and on the coast of Somalia, on the African coast. It was only in 2005 that it was possible to obtain clearer images of the waters for the first time and compare them with observations made on a ship.
)Satellite view of the milky seas. (Source: Wikimedia)
Light beings
At first, scholars believed that dinoflagellates would be responsible for emitting the glow, being a way of reacting to disturbances in the sea, either by the effect of the breaking of the waves or by other external causes. But as this species produces a short-range and long-lasting glow, this hypothesis was eventually discarded. The perception that milky seas are present in calmer areas of the ocean also contributed to this.
Further on, the analysis of the waters indicated the presence of the bacteria V. harveyi and microalgae Phaocystis, explaining the reason for the intense brightness: the bacteria colonized the algae and had the emission of light in an efficient way to attract the fish, because it is in the intestine of these animals where the micro- organisms find their ideal habitat.
Despite the intense shine, it is during the night that the effect draws the most attention. (Source: Wikimedia)
Study brought important data
In research conducted by Steven D. Miller, professor of atmospheric science, records showed that the range of this event covered an immense area of the sea, which can extend over a range of up to 100,000 km². The study, conducted between 2012 and 2021 and published in Nature Scientific Reports also concluded that the bacteria only glowed with greater intensity when concentrated in a large volume.
In addition, the investigation made it possible to observe cases in which the waters were illuminated for days and even weeks. Although expressive, the phenomenon of milky seas is rare, occurring only three times a year and with greater recurrence in the Indian Ocean – which may explain the difficulty in obtaining images and more information.
And if the researchers’ work has allowed significant advances to be made, it still does not mean that all questions have been answered. Today, the understanding is that it is still necessary to know more about the action of these beings, but the study took an important step to help us understand a little more about marine life.
