For the first time, Indian ocean scientists have captured an image of an active hydrothermal vent located 4,500 meters below the surface of the Indian Ocean. The site has potential for mineral exploration as part of the Rs 4,000 crore Deep Ocean Mission under the Ministry of Earth Sciences.
Hydrothermal vents, mostly found near tectonic plates, are underwater vents where cool water (about 2 °C) near the seafloor comes into close contact with magma (rock formed at very hot temperatures inside the Earth) in tectonically active areas. When this cold water flows through cracks and fissures in the oceanic crust and mixes with magma, it heats up. It can turn into superheated water (up to 370°C) and then escape through chimneys and vents as mineral- and gas-rich plumes.
The National Center for Polar and Ocean Research (NCPOR) in Goa has conducted several geophysical surveys since 2012 in search of hydrothermal vents in the central and southern ridges of the Indian Ocean. In the process, they look for temperature anomalies and turbidity of the water column in potential areas where hydrothermal vents may be populated.
In April this year, the NCPOR team narrowed down the search for a specific site along the Central Indian Ridge with the help of an Automated Underwater Vehicle (AUV). The high-resolution imaging was carried out by a joint research team of NCPOR and the National Institute of Ocean Technology (NIOT), Chennai. This collaboration focused on high-resolution deep-sea exploration and imaging of hydrothermal sulfide fields in the central and southwest Indian Ridges in the southern Indian Ocean.
Senior Scientist John Kurian of NCPOR and NR Ramesh of NIOT led the Hydrothermal Exploration Program and the AUV mission. A few days ago, during a recent observation mission, an Indian AUV launched from a research ship named Sagar Nidhi took a historic picture. Observation lasted from 12 to 15 hours.
“We could capture images of an active hydrothermal vent. It showed vent chimneys, black smokers and gave some indications of living chemosynthetic organisms,” John Kurien, group director of deep sea exploration at NCPOR, told The Indian Express.
The discovery could significantly enhance India’s deep ocean missions, particularly submarine missions, focusing on mineral exploration from inactive vents.
“The latest findings visually confirm our previous detailed near-bottom surveys, which identified several potential locations of active vents through which hot magma fluids exposed to the sea floor were observed. This (discovery) will intensify Indian exploration activities in the deep sea, ” said NCPOR Director Thumban Meloth.
Furthermore, this latest discovery may provide scientists with new opportunities to gain better insight into organisms living in environments supported by hydrothermal vents. Just as land plants use sunlight to photosynthesize and produce food, underwater microbes rely on chemicals rich in minerals and metals for their sustenance.
According to Kurien, hydrothermal vents can remain active for a few hundred to 30,000 years. This makes them essential for exploration from both economic and biological perspectives. Deposits formed from hydrothermal venting are believed to be rich in precious minerals and metals, including copper, zinc, gold, silver, platinum, iron, cobalt and nickel.
In the next phase of the study, NCPOR plans to conduct TV-guided grab sampling, which may reveal more detailed associated features and the economic potential of these vent deposits.
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