Scientists have discovered a previously undiscovered body of water in the middle of the Atlantic Ocean: a huge body of water that extends across the Atlantic Ocean from the tip of Brazil to the Gulf of Guinea, near West Africa.
The body of water, called the Atlantic Equatorial Waters, forms along the equator when ocean currents mix separate bodies of water to the north and south.
Until the discovery of Atlantic tropical waters, scientists had observed water mixing along the equator in the Pacific and Indian Oceans, but this had never happened in the Atlantic Ocean. The researchers published their findings on October 28 in the journal Geophysical Research Letters.
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“It seems controversial that the tropical water mass is present in the Pacific and Indian Oceans but is missing in the Atlantic because tropical circulation and mixing in all three oceans have common features.” Victor ZorbasThe physicist and oceanographer at the Shirshov Institute of Oceanography in Moscow told Live Science in an email. “The new identified water mass allowed us to complete (or at least describe more accurately) the phenotype of the basic water masses in the World Ocean.”
Far from being the same everywhere, ocean water is a vast mixture of interconnected masses and layers, mixed together and divided again by currents, eddies, and changes in temperature and salinity.
Water masses are the characteristic parts of this diverse arrangement; Each body of water has a common geography, formation history, and physical properties, such as density, dissolved oxygen isotopes, nitrates, and phosphates.
To characterize water masses, oceanographers plot the relationship between temperature and salinity across the ocean, two measurements that combine to determine the density of seawater.
In 1942, this graph of temperature and salinity led to the discovery of tropical waters in the Pacific and Indian Oceans. The tropical waters of the Indo-Pacific are formed by the mixing of waters from the north and south, and have temperatures and salinities curved along lines of constant density that are easily distinguishable from the surrounding waters. However, it has not been possible to observe such a relationship in the Atlantic Ocean.
To search for the missing mass of water, scientists combed through data collected by the Argo program, an international group of automated, self-submersing buoys spread across the world’s oceans.
After analyzing data collected by this floating array, the researchers observed an unobserved temperature and salinity curve, which lies parallel to the curves that define the North Atlantic and South Atlantic waters central to the north and south: the tropical Atlantic waters.
“It was easy to confuse tropical Atlantic waters with the central waters of the South Atlantic, and in order to distinguish between them it was necessary to have a fairly dense network of vertical temperatures and salinities covering the entire Atlantic Ocean,” Zorbas said.
Now that the water mass is determined, it will give scientists a better understanding of ocean mixing processes, which are vital for transporting heat, oxygen and nutrients in oceans around the world, Zorbas said.
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