Ancient underwater mountain range discovered in Southern Ocean

News Excerpt:

Scientists have discovered an ancient underwater mountain range hidden within the world's strongest ocean current, the Antarctic Circumpolar Current.

About the findings:

  • The discovery was made by researchers on board a research voyage - FOCUS, in the Southern Ocean by Australian government agency the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
  • The researchers were originally working to study the Antarctic circumpolar current to understand better how it contributes to rising sea levels.
    • In particular, they were looking at how the current leaks heat towards the continent.
  • The research vessel Investigator (RV-Investigator) explored a vast area of the Southern Ocean, stretching 20,000 square kilometres between Tasmania and Antarctica.
  • A chain of eight long-dormant volcanoes with peaks soaring up to 1,500 meters was revealed.
    • Four of the eight long-dormant volcanoes are new discoveries.
  • Other findings include detailed information on previously partially mapped seamounts and a fault line ridge.
  • The survey area, located 200 nautical miles west of Macquarie Island, sits atop the tectonically active Macquarie Ridge, where these seamounts were formed by hotspot magmatism within the last 20 million years.

About the FOCUS voyage:

  • The research voyage - FOCUS was designed to complement the capabilities of the new Surface Water and Ocean Topography (SWOT) satellite (developed jointly by NASA and the French space agency CNES).
  • It is a high-resolution mapping expedition conducted by an Australian and international research team.
  • This collaboration allowed for simultaneous mapping from both space and sea, providing a comprehensive view of the ocean's fine-scale features.

Geological Significance:

  • The underwater mountain range provides key evidence of plate tectonics, the movement of Earth’s crust, and the formation of new landmasses.
  • The discovery raises intriguing questions about the relationship between underwater mountains and the surface landscapes they may be connected to.
    • Further research could investigate whether similar mountain ranges exist on land and whether they share a common origin.

Implications for Climate and Ecosystems:

  • These underwater peaks can act as barriers, influencing ocean currents and affecting nutrient distribution.
    • Understanding the impact of these formations on ocean dynamics is crucial for predicting climate patterns and better managing marine resources.
  • The ridges and valleys provide sheltered zones where marine life can thrive, with the potential for new species discoveries.
    • Protecting these habitats will be critical in preserving the delicate balance of marine ecosystems.


Oceans act as “climate shock absorbers” by absorbing over 90% of the heat from global warming and about 25% of human CO2 emissions. The seafloor's topography plays an important role in influencing ocean dynamics. By studying the composition and structure of these underwater formations, scientists can gain insights into the geological processes that have shaped the planet over millions of years. Additionally, these underwater mountains create a unique habitat for a diverse range of marine species.

Antarctic Circumpolar Current (ACC):

  • It extends from the sea surface to the bottom of the ocean and encircles Antarctica.
    • The ACC is created by the combined effects of strong westerly winds across the Southern Ocean and the big change in surface temperatures between the Equator and the poles.
  • The Antarctic Circumpolar Current interacts with the seafloor, creating eddies that transport heat and carbon deeper into the ocean, thus serving as a buffer against global warming.
    • Moving northward, away from Antarctica, the water temperatures rise slowly at first and then rapidly across a sharp gradient. It is the ACC that maintains this boundary.
    • It is vital for Earth’s health because it keeps Antarctica cool and frozen.
    • Scientists are studying the current to find out how it might affect the future of Antarctica’s ice sheets and the world’s sea levels.
  • It provides the main connection between the Indian, Pacific and Atlantic Oceans.

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