Samudrayaan

With Samudrayaan, the Deep Ocean Mission, India is diving into the dark waters of the abyssal zone of the Central Indian Ocean Basin. This mission aims to collect polymetallic nodules, study deep-sea marine life, and research climate change to bolster India's blue economy. Now India has joined the select group of countries- the USA, France, Russia, Japan, and China who have the technology to conduct deep-sea studies.

Getting ready for Mission Samudrayaan Source: The Hindu

Polymetallic nodules are tiny porous rocks rich in copper, nickel, manganese, and cobalt. The nodules are mineral-rich deposits and are found scattered abundantly on the seafloor, at depths of 4000 metres to 6000 metres.

Polymetallic nodules scattered on the sea floor   Source: Wikimedia Commons

Polymetallic nodules  Source: Wikimedia Commons

This layer of the ocean is called the abyssal zone. Here, the ocean is pitch black with no sunlight penetrating from above and the pressure is about 600 times more than the pressure experienced by us at sea level.  Regular submersible crafts would implode under this enormous pressure.

Site of the polymetallic nodules: the abyssal zone  Source: Pinterest

Matsya 6000 is a  specially designed titanium alloy submersible that can withstand deep sea pressure safely.  This spherical craft has a diameter of 2.1m and can carry three aquanauts. The craft has the capability to remain operable on the seafloor for 12-16 hours at a time and has a continuous oxygen supply for 96 hours in case of an emergency.   Equipped with sensors, it can scout, detect, and mine the seafloor for the nodules. Matsya 6000 has been designed by scientists of the National Institute of Ocean Technology, Chennai (NIOT) in collaboration with ISRO, DRDO (Defence Research and Development Organisation), and researchers from IIT Madras.

The Submersible Matsya 6000 Source: DNA India

Deep-sea mining involves the extraction of minerals from the sea bed from depths more than 200m. Governments around the world are exploring and researching the pros and cons of deep-sea mining.

How much havoc will be caused in the marine ecosystem or whether it will cause entire species to go extinct is not known and therefore a matter of great concern.  The risk of destroying underwater habitats and biodiversity is very high.

DSM vehicles disturb the ocean floor during the digging, dredging, and vacuuming process.  Large plumes of sediments form and they drift along the ocean currents disrupting the ecosystem.  They also wreck the seabed leading to the release of harmful greenhouse gases like methane.

Many environmentalists and activists do not advocate deep-sea mining without a proper impact assessment.

A drifting sediment plume created by a deep sea mining vehicle on the seafloor.  Source: NOAA/DeepCCZ expedition

Creatures of the deep sea.Source: Wikimedia Commons

But with the depletion of mineral deposits on land, high levels of pollution, scarring of the landscape by open pits, and the rising cost of terrestrial mining, deep sea mining seems to be a better option to meet the demands of industry.

Copper mine at Jharkhand, India Source: Newsclick

The primary rationale for the implementation of Mission Samudrayaan is to reduce the dependency on fossil fuels and meet energy demands in a sustainable manner. The metals in the polymetallic nodules are used to make the batteries of electric vehicles. The International SeaBed Authority (ISA) has allocated rights to India over an area of 75,000 sq km in the Central Indian Ocean Basin for deep sea mining. The reserves of the polymetallic nodules on the ocean floor are so large that just ten percent of the nodules can provide for the energy needs of India for the next hundred years.

The Indian Ocean Nodule Field in the Central Indian Ocean BasinSource: Researchgate

With the goals of the government to reduce the carbon footprint, transportation needs to go green by increasing the use of electric vehicles. It does not make sense to charge a battery with power generated by a coal-based thermal power plant, so renewable sources of energy like tidal energy have to be harnessed. Research is underway for offshore Ocean Thermal Energy Conversion (OTEC) to power desalination plants along the coast of India.  This is to support off-shore energy development following the Blue economy policy. The Indian government’s efforts for the growth of a blue economy stem from the firm belief that it is possible to have economic, environmental, and social sustainability. Such growth would generate employment, conserve coastal and marine environments, promote green energy, and take care of India’s future energy needs sustainably.