‘Biorock or mineral accretion technology’

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.

Locating the 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.
• A biorock structure has been installed one nautical mile off the Mithapur coast in the Gulf of Kachchh.
• The location for installing the biorock had been chosen keeping in mind the high tidal amplitude in the Gulf of Kachchh.
• The low tide depth where the biorock has been installed is four metres, and at high tide it is about eight metres.

About the technology:

• Mineral Accretion Technology is a coral reef restoration technology that utilizes low voltage electricity to improve the health and growth rates of corals and other marine organisms. 
• The technology works by passing a small amount of electrical current through electrodes in the water.
• When a positively charged anode and negatively charged cathode are placed on the sea floor, 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.
• Fragments of broken corals are tied to the biorock structure, where they are able to grow 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.

What are Coral Reefs?

• Coral reefs are the large number underwater strutcures composed of the skeleteon of the colonial marine invertebrates known as ‘coral’. 
• Each individual coral animal is called a ‘polyp’. Most of them live in groups of thousands of genetically identified polyps that form a ‘colony’, which is created by a process called budding, where the original polyp grows copies of itself. 
• Coral are invertebrates belonging to group of Cnidarians. They are generally classified into two groups:
  • Hard or hermatypic corals: They extract calcium carbonate from seawater to create a hard, durable exoskeleton that protects their bodies. 
  • Soft corals: They are flexible organisms and resembles trees and plants. 

Threat to Coral Reefs:

• Ocean warming: Corals cannot survive in high water temperature. Global warming has already led to increased levels of coral bleaching.
• Pollution:Pollution arising from urban and industrial waste, sewage, agrochemicals, and oil pollution are poisoning reefs increases the level of nitrogen in seawater, causing an overgrowth of algae, which smothers reefs by cutting off their sunlight.
• Destructive Fishing Practices: Destructive fishing practices such as cyanide fishing, dynamite fishing, bottom trawling, and muro-ami, bottom-trawling are some greatest threats to cold-water coral reefs.
• Overfishing:Overfishing adversely affects the ecological balance of the coral reef, disturbing the food chain. 
• Sedimentation:Furthermore, erosion caused by construction, mining is leading to increased sediment in rivers, which ends up in the ocean. In addition to this, the destruction of mangrove forests, which generally trap large amounts of sediment, is exacerbating the problem.

Significance of the initiative:

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