The “Missing” Water Mass in the Atlantic

Researchers have recently discovered a previously unidentified water mass in the Atlantic Ocean, challenging previous assumptions about the ocean's composition. The findings, reported in the journal Geophysical Research Letters, highlight the importance of advanced technology in ocean research. The Atlantic Equatorial Water mass, formed by the mixing of South Atlantic Central Water and North Atlantic Central Water, was found to extend from the tip of Brazil to the Gulf of Guinea. Prior to this discovery, researchers had assumed that the South Atlantic Central Water occupied this space. The confusion between the two water masses was only dispelled through meticulous analysis of extensive data collected by the Argo. The Argo program, consisting of an array of robotic floats strategically placed throughout the ocean, played a pivotal role in uncovering this “missing” component of the Atlantic. These floats, equipped with sensors, autonomously dive and resurface, collecting vital data about the ocean's physical properties. The density of seawater, determined by its temperature and salinity, varies among different water masses, emphasizing the complexity of the ocean's composition. While the Pacific and Indian Oceans had previously revealed the existence of distinct equatorial water masses, the absence of such a phenomenon in the Atlantic had raised questions among scientists. "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. The identification of this missing water mass in the Atlantic not only resolves this controversy but also sheds more light on the Atlantic Ocean’s dynamics and contributes valuable insights to the field.

Reference

Zhurbas, V., Lebedev, K., & Kuzmina, N., 2023. Is there the Equatorial Water mass in the Atlantic Ocean? Geophysical Research Letters, 50, e2023GL104866. doi: 10.1029/2023GL104866