The Zoological Survey of India (ZSI), with help from Gujarat’s forest department, is attempting for the first time a process to restore coral reefs using biorock or mineral accretion technology off the Mithapur coast in the Gulf of Kachchh

Zoological Survey of India (ZSI)

  • Its origin can be traced to the Museum of the Asiatic Society of Bengal (1814-1875) and the Zoological Section of the Indian Museum (1875-1916) in Kolkata. 
  • Thomas Nelson Annadale was the founder-director of ZSI, who joined the Indian Museum as a deputy superintendent and was later promoted to the position of the superintendent. 
  • The Zoological Survey of India (ZSI) was launched in 1916, so this year, it is celebrating its centenary year. It is India’s apex organization on animal taxonomy and has significantly contributed to knowledge on the fauna of the country.
  • As of now, ZSI has 16 regional centers spread across the country. Its head headquarters are at Kolkata

What is biorock?

  • Biorock is the name given to the substance formed by electro accumulation of minerals dissolved in seawater on steel structures that are lowered onto the sea bed and are connected to a power source, in this case, solar panels that float on the surface. 
  • The technology works by passing a small amount of electrical current through electrodes in the water.
  • When a positively charged anode and the negatively charged cathode are placed on the seafloor, with an electric current flowing between them, calcium ions combine with carbonate ions and adhere to the structure (cathode). 
  • This results in calcium carbonate formation. Coral larvae adhere to the CaCO3 and grow quickly (at least four to six times faster than their actual growth as they need not spend their energy in building their own calcium carbonate skeletons). 

The reason behind choosing the Gulf of Kachchh

  • The location for installing the biorock had been chosen to keep in mind the high tidal amplitude in the Gulf of Kachchh. 
  • The low tide depth where the biorock has been installed is four meters, and at high tide, it is about eight meters. 

The real success will come when the attached and new organisms (corals) grow faster and the process can be scaled up.

Threats were posed both by climate change-induced acidification as well as by anthropogenic factors. 

The ongoing initiative of coral restoration using biorock technology could potentially help to sustain the earlier successes. The technology helps corals, including the highly sensitive branching corals, to counter the threats posed by global warming.

Coral Reef

Corals are animals in the same class (Cnidaria) as jellyfish and anemones. They consist of individual polyps that get together and build reefs. Coral reefs are important hotspots of biodiversity in the ocean. 



  • Coral reefs maintain the quality of the coastal biosphere and support a wide range of species.
  • Corals convert the carbon dioxide in the water into a limestone shell and thus control the level of carbon dioxide in the water. 
  • This maintains the amount of carbon dioxide in the ocean water and thus saves ecological niches from destruction.


  • By climate change.
  • Undergo a process of bleaching, when the sea surface temperature increases beyond a tolerable limit.  

What is bleaching?

  1. Basically bleaching is when the corals expel certain algae known as zooxanthellae, which live in the tissues of the coral in a symbiotic relationship. 
  2. About 90% of the energy of the coral is provided by the zooxanthellae which are endowed with chlorophyll and other pigments. 
  3. They are responsible for the yellow or reddish-brown colors of the host coral. In addition, the zooxanthellae can live as endosymbionts with jellyfish also.
  4. When a coral bleaches, it does not die but comes pretty close to it. Some of the corals may survive the experience and recover once the sea surface temperature returns to normal levels.

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