26 June 2025
At first glance, coral reefs may appear to be nothing more than colorful rocks beneath the sea. In reality, they are the foundation of marine life—providing food, shelter, and protection for more than 25% of the world’s marine species.
Indonesia is home to the largest expanse of coral reefs in the world, covering an estimated 51,000 square kilometers—around 18% of the world’s total coral reef area, which spans approximately 284,300 square kilometers. Even more remarkable, Indonesia is located within the Coral Triangle, making its reefs not only vast but also incredibly diverse.
Coral reefs are natural structures formed by colonies of tiny marine animals called coral polyps, which live in symbiosis with microalgae known as zooxanthellae. These colonies deposit calcium carbonate as they grow, creating the hard surfaces that serve as a habitat for thousands of marine species.
Interestingly, coral polyps belong to the phylum Cnidaria, which also includes jellyfish—making them distant relatives!
Coral reefs provide vital benefits to both marine ecosystems and human communities:
Coral reefs are generally classified into three main types:
As a mining company operating on Obi Island, Harita Nickel recognizes the critical role marine ecosystems—particularly coral reefs—play in maintaining environmental balance. The company is committed to actively contributing to their preservation through various ongoing initiatives.
Since 2021, Harita Nickel has been developing reef cubes—hollow concrete blocks made from a mix of cement, nickel slag, and fly ash—that serve as artificial substrates for coral growth. By the end of 2024, a total of 1,871 reef cubes had been deployed on the seabed.
Harita Nickel’s Environmental Marine team conducted observations from October 2022 to December 2024 and reported that natural coral growth ranged from 0.93 cm to 6.64 cm—well above the average natural growth rate of 0.3 cm to 2 cm per year.
In addition, 136 species of reef fish from 61 genera and 24 families were recorded in the coral restoration areas.
Harita Nickel does not discharge production waste into the sea. Instead, the company has built sediment ponds to filter runoff water from mining operations, preventing excessive sedimentation that could harm coral reefs.
Harita Nickel’s dedicated Environment Marine Division is tasked with ensuring that the waters around Obi Island remain in good condition.
The team conducts daily, monthly, and quarterly monitoring of marine conditions. Every six months, the company also partners with independent experts to conduct comprehensive water quality testing around Obi Island.
Through this monitoring, Harita Nickel can identify potential risks early and implement corrective actions to help maintain the health and sustainability of the local marine ecosystem.
Coral reefs are not only essential for life beneath the waves but also for human well-being. Through collective conservation efforts by local communities, governments, and responsible industries such as Harita Nickel, we can help safeguard these vital ecosystems for generations to come.
As a nation blessed with extraordinary marine biodiversity, Indonesia carries a significant responsibility to serve as a global steward of coral reef conservation.
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