Researchers Finally Found the Huge ‘Missing’ Blob of Water in the Atlantic Ocean
Far from how it appears on the surface, ocean water is not the same everywhere. Rather, it is a striking medley of interlinking waters that deluge from the opposing directions of the Northern Hemisphere and the Southern Hemisphere. Like monsters of different shapes, colors, and sizes, the water is sculpted differently in different portions of the ocean. Even the subsurface water which is warm, is different from the cooler deep waters that form the ocean. This see-saw dance between these hot and cool waters generates something oceanographers call a “water mass.” In a study published in Geophysical Research Letters, researchers documented the discovery of a gigantic water mass convulsing in previously disregarded locations of the Atlantic Ocean.
Water masses are usually differentiated based on their temperature, salinity, isotope ratios, currents, eddies, and chemical compositions, per ScienceDirect. A water mass that forms along the equator, separating the waters from the north and the south, is called an “equatorial water mass.” From previous studies, researchers were aware that equatorial water masses already existed in the Pacific and the Indian Ocean. In 1942, they charted the temperature and salinity of these oceans to affirm the existence of equatorial waters. But never did anyone find such a mass in the Atlantic Ocean, which was strange, because even the Atlantic’s waters had the same equatorial properties as the other two oceans.
"It seemed controversial that the equatorial water mass is present in the Pacific and Indian oceans but missing in the Atlantic Ocean because the equatorial circulation and mixing in all three oceans have common features," Viktor Zhurbas, a physicist and oceanologist at The Shirshov Institute of Oceanology in Moscow, told Live Science. It wasn’t until a team of researchers from this institute employed the Argo program to re-examine the Atlantic, that they came upon this anticipated discovery. Launched in 1998, the Argo program was designed to collect information from inside the ocean using fleets of robotic instruments that drift with the ocean currents and move up and down between the surface and a mid-water level.
While investigating the Atlantic from the tip of Brazil to the Gulf of Guinea, near West Africa, they found a water mass they termed the “Atlantic Equatorial Water (AEW).” “Re-examination of water masses using previously unavailable high-quality large volume Argo data allowed us to distinguish a formerly unnoticed water mass in the main thermocline of the Equatorial Atlantic and thereby complete the phenomenological pattern of basic water masses of the World Ocean,” the team wrote in the paper. They further elaborated that the gigantic blob was, most likely, formed by the mixing of the South Atlantic Central Water and the North Atlantic Central Water.
"It was easy to confuse the Atlantic Equatorial Water with the South Atlantic Central Water, and in order to distinguish them it was necessary to have a fairly dense network of vertical temperature and salinity profiles covering the entire Atlantic Ocean," Zhurbas told Live Science. “Now that the water mass has been identified, it will give scientists a better understanding of the ocean's mixing processes, which are vital to the oceans' transport of heat, oxygen, and nutrients around the globe,” he added.