It is curious how unknown the ocean is to humans, considering how much it occupies and its tremendous importance on the planet that we believe we dominate. According to retired Vice Admiral Shin Tani: “We know more about the topography of Mars than about the floor of our planet’s oceans.” The reason is not only that more resources are allocated to space exploration than to ocean exploration, but that underwater mapping, according to Tani, “is a difficult undertaking.”
In fact, humans have been more times on the Moon than on the bottom of the sea. On World Oceans Day, we review some things we know about our seas, and many others that we still have to explore.
How much water is there on our planet?
Specifically, according to the NOOA (National Oceanic and Atmospheric Administration), more than 70% of the Earth is made up of H2O, a percentage of which the oceans represent 96.5%. This means that most of the water on our planet is not drinkable for us, but is part of an ecosystem incredibly rich in biodiversity, and that it is essential to maintain the ecological balance of the planet (and our survival on it).
How many species live in the sea?
To our knowledge, some 130,000 different species live in the Earth’s oceans, according to the Ocean Biodiversity Information System (OBIS). However, this same organism recognizes that we still do not know more than a third of all ocean life that could exist. It is amazing to imagine how many unexplored wonders could be hidden in the depths of our oceans.
How deep is the ocean?
The kind of abyss we are talking about is highly variable. The average depth of the ocean is believed to be about 3,900 meters, with the Mariana Islands Trench being the deepest place on Earth, at about 11,000 meters. At such a distance from the surface, the creatures that exist there survive in complete darkness and only about four degrees of temperature. For example, xenophiophores, single-celled creatures from the kingdom of protists that live in large sponge-like colonies, are spread across most of the deep sea beds, between 4000 and 6000 meters; and in the hadal areas, more than 6000 meters deep.
Species such as slimy fish, other fish with large teeth, shiny jellyfish, giant squid, various crustaceans or sea cucumbers, to name a few that we are aware of, also live several thousand kilometers deep.
Today we know that life originated in the oceans about 3.5 billion years ago, and that it ‘moved’ to the mainland only when conditions were favorable (an ozone layer thick enough to protect organisms from deadly radiation). ).
Why we need to explore the oceans
The answer goes beyond the mere obtaining of knowledge. Underwater exploration studies the physical and chemical properties of seawater, all kinds of life in the sea, and the geological and geophysical characteristics of the earth’s crust. This analysis enables scientists to predict, for example, long-term climate and meteorological changes and leads to more efficient exploration and exploitation of the Earth’s resources, which in turn translates into better management of the environment overall. .
From ‘Challerger’ to today, a century and a half of underwater exploration
The British ship Challenger expedition between 1872 and 1876 was the first major underwater survey. Although his main objective was the search for life in deep waters by means of net trawls, the results of his physical and chemical studies expanded the scientific knowledge of the distribution of temperature and salinity in the open sea.
In addition, depth measurements were made using cable probes throughout the world during the expedition.
Since that first mission, scientists have studied the seas for the next century and a half, producing global maps showing the distribution of surface winds, as well as heat and rain, which work together to propel the ocean in its incessant motion.
So it was discovered, for example, that surface storms can penetrate the ocean causing sediments in the deep sea to ripple and move. Recent studies have also revealed that tornadoes occur within the ocean and that the climate anomaly known as El Niño is caused by an interaction of the ocean and the atmosphere.
The role of the ocean in moderating the Earth’s climate
Other research has shown that the ocean absorbs large amounts of carbon dioxide and therefore plays an important role in delaying its accumulation in the atmosphere.
The ocean plays a fundamental role in what is known as the carbon cycle. CO2 is largely stored in the seas. Without the moderating effect of this retention by the ocean, the constantly increasing entry of carbon dioxide into the atmosphere (due to the extensive burning of coal, oil and natural gas) would result in the rapid onset of the greenhouse effect, a global warming caused by absorption and re-entry of infrared energy into the earth’s surface by carbon dioxide and water vapor in the air.
The oceanic crust that shapes the appearance of our planet
Thanks to the underwater exploration carried out by the human being, which allowed us to know a little more about the seabed and its gravitational and magnetic properties, the human being has been able to identify patterns of movement of the continental plates. These patterns form the basis of the concept of plate tectonics, which synthesized earlier hypotheses of continental drift and seafloor expansion. Plate tectonics revolutionized the scientific understanding of the Earth, since it allowed us to understand phenomena such as volcanism, seismic activity and the formation of mountains.
The treasures that the sea keeps
As if they were few, the biological treasures that the ocean hides in the seabed are important deposits of metals. Hydrothermal circulations produce considerable accumulations of metals important to the world economy, such as zinc, copper, lead, silver and gold. Not to mention oil, a lethal fuel that does so much damage to our planet and that is nothing more than the remains of animals and plants that died millions of years ago, and whose remains were deposited on the bottom of the sea, heating and degrading.
The bottom of the sea: a horizon to conquer … and to preserve
As will happen with the resources of space, as we expand the exploration of other worlds outside the Earth, International Law must deal with the resources of the depths of the sea. There is a horizon in our own home even more ambitious than some flags placed on worlds outside our planet. It is everyone’s job, with the help of scientific and technological progress, to take care of it and maintain it to preserve the delicate order that gives habitability to the Earth.
