A Sea of Artificial Coral Reefs

Coral reefs, also known as the rainforests of the ocean, are among the most biologically diverse and colorful ecosystems on Earth. According to the U.S. Environmental Protection Agency (EPA), one-quarter of all marine life depends on coral reefs to survive. However, many reefs are struggling for existence because of mass bleaching.

Chemists at the Univ. of Cambridge have developed a 3D-printed artificial coral structure that can host zooxanthella, a photosynthetic algae. These synthetic systems can use photosynthesis to make sugars, mimicking the natural symbiosis between algae and coral. The development could help scientists better understand and thus alleviate coral bleaching, and someday even help them create artificial coral reef systems.

Most corals are characterized by their hard skeletons, which are made of calcium carbonate derived from dissolved calcium in the surrounding seawater. The skeleton provides mechanical support for a soft tissue layer, and inside this tissue are a photosynthetic algae known as zooxanthellae.

These organisms live in symbiosis with the coral, absorbing light for photosynthesis that produces sugars for the coral to consume. In return, the algae gain important nutrients such as carbon dioxide and nitrogen.

Zooxanthellae are responsible for coral reefs’ vibrant, abundant colors. However, with the introduction of stressors such as elevated ocean temperatures, the algae will quickly leave the coral to find shelter elsewhere.

In their absence, the coral turns milky white and pale, a phenomenon known as bleaching. Severe bleaching can destroy entire reefs. From 2014 to 2017, the world experienced its most widespread and damaging...