An Unplanned Coral Garden
The Colombo Port City project reclaimed 269 hectares of land from the sea, a process that required 65 million cubic meters of dredged sand. To protect this new landmass from the Indian Ocean's powerful waves, engineers constructed a massive 3.2-kilometer-long breakwater. The structure, built from granite and concrete armor units, became one of the region's largest artificial reefs and a laboratory for marine succession.
The breakwater's rough surfaces and stepped design created an ideal substrate for marine organisms to attach and grow. Colonization began soon after construction. A diver first noticed the initial coral growth in 2019. Since then, scientific surveys have documented a rapid settlement of life. A 2023 study conducted by researchers from institutions including the University of Ruhuna and the Chinese Academy of Sciences found 74 coral species and 137 species of fish inhabiting the structure. In some areas, live coral cover reached over 50 percent. The dominant coral species establishing itself is Pocillopora damicornis, a type of cauliflower or brush coral.
A Living Laboratory
The breakwater provides a unique, large-scale experiment in marine ecology. Scientists are studying the sequence of colonization, from the first algae and barnacles to the communities that follow. This includes monitoring the growth of over 70 types of coral and observing more than 100 fish species that now use the reef for food and shelter. Among the fish documented are species like the Moon wrasse (Thalassoma lunare) and Yellowtail fusilier (Caesio cuning). The endangered Humphead wrasse has also been observed in the area.
To further assist the process, marine biologists have established artificial coral nurseries. Since 2024, conservation efforts have added 68 coral nursery groups to cultivate over 5,000 individual coral plants. In a separate initiative, 13 decommissioned vessels were sunk in the channel between the breakwater and the beach to create an underwater shipwreck museum, providing additional habitats for marine life. These combined efforts create a dynamic environment for studying how marine ecosystems can establish on artificial structures, providing data for future coastal engineering projects worldwide.