As rising ocean temperatures and acidity are wiping off coral reefs at an unprecedented rate, researchers are on a continuous quest to better understand these fascinating ecosystems and to find ways to prevent their mass extinction.

Aligned with such a mission, scientists from Cambridge University have recently 3D printed coral-inspired structures that, apart from representing a reef base, are built out of microorganisms that allow algae to flourish by enabling photosynthesis.

Previously, other researchers have also used 3D printing to build structures that resemble the complex shapes of reefs as solid bases on which new corals and other animals could grow. It’s a good idea, but there’s more to a reef than a solid base: corals are in fact a highly evolved symbiosis between the coral organisms themselves and algae that live inside them.

For their part, the algae use photosynthesis to power the creation of sugar for their host, and the coral provide a safe living environment — and, interestingly, are also highly efficient at collecting and redirecting light. This partnership has been fruitful for millions of years, though climate change has upset the delicate balance necessary for success.

The team at Cambridge realized that to successfully imitate the coral micro-ecosystem, they’d need to replicate that special quality of capturing sunlight and diffusing it within for use by resident algae. To do so, they studied the structure of corals closely and worked to remake it at a microscopic level. But instead of using an ordinary durable substrate, they created a sort of living gel.

The resulting bioprinted structure is an ideal home for the algae, producing growth rates many times the speed of an ordinary medium. This type of simulation could lead to a better understanding of the ecosystem in which the coral-algae partnership thrives, and how it can be nurtured.