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Roadmap to Coral Reefs: Stop Here First!

Although most people reading our blog already have a strong appreciation for corals and reef ecosystems, we thought that it might be helpful to go back to the basics and remember why we love them so much. We're rolling out our “Roadmap to Coral Reefs”, a miniseries which will answer some fundamental questions about these remarkable animals and why they desperately need our protection.


Corals as we know them are actually colonial organisms, made up of thousands of smaller animals known as polyps. These polyps are tiny organisms classified in the phylum cnidaria, which means they're closely related to jellyfish! At the base of each polyp is a limestone skeletal structure known as a calicle. These calicles connect to one another to form the larger colony we commonly know as a coral.

Close-up images of a Pillar coral (left) and Staghorn coral (right). © Alex Neufeld/Coral Restoration Foundation™


We often immediately associate coral reefs with their trademark vibrant hues. However, coral skeletons are naturally white and their polyps are translucent. All of the dazzling colors we see are actually from a type of micro algae, known as zooxanthellae. Zooxanthellae live inside each polyp, providing the coral with essential nutrients and photosynthetic compounds. Because every mutualistic relationship involves some give and take, the coral returns the favor by giving the zooxanthellae a place to live. The phenomenon known as coral bleaching occurs when corals become stressed, causing them to expel their algae symbionts and reveal their stark white skeleton.

A vibrant, healthy elkhorn colony. © Alex Neufeld/Coral Restoration Foundation™


Corals can’t exactly move around to meet other corals, so they reproduce through a unique process known as spawning. During spawning, corals release billions of colorful gametes into the surrounding water in a flurry that resembles a blizzard.

Staghorn corals releasing gametes during spawning in the CRF™ Tavernier Nursery. © Alex Neufeld/Coral Restoration Foundation™

The male and female gametes combine to create embryos, which develop into larvae called planulae. Planulae float in the water column for days or weeks until they drop to the seafloor and attach to the substrate. Colonies will synchronize their gamete release to increase the chances of both fertilization and a favorable genetic combination, which perhaps will be more resilient in future conditions.

At Coral Restoration Foundation™, we predominately work to restore populations of staghorn, elkhorn, and boulder corals.

At Coral Restoration Foundation™, we work to support the reefs’ natural recovery processes through the large-scale cultivation, outplanting, and monitoring of genetically diverse, reef-building corals. We primarily focus on restoring populations of staghorn (Acropora cervicornis), elkhorn (Acropora palmata), and two species of boulder coral (Orbicella faveolata and Obricella annularis). To learn more about our work, visit

Stop back next week to read the second edition of “Roadmap to Coral Reefs” where we're talking about how coral reefs are formed!


REEFocus Editorial Intern

Indira Khera is a third year at the University of Chicago from Simsbury, Connecticut. She is majoring in Biology with a minor in Environmental Studies. Indira has always been passionate about marine ecology, an interest that started with her childhood summers in coastal Maine. On campus, she works in a Cognitive Neuroscience laboratory, sits on the board of UChicago Women in Science, and writes for the University's Research Magazine, The Triple Helix. Indira is so excited to be a part of the CRF™ team as our Research and Writing Intern.

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