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  • Brynn Young Marine Biology

Cryogenic Coral Sperm Banks Making Coral Sexy Again

Updated: Aug 7, 2020

You’ve probably heard a lot about coral reefs in today’s changing world. About how the climate is affecting them and their impending doom. The effects of warming oceans on coral is real and shocking, but have you heard about why we’re optimistic about their future? Simply put, our hope comes from sperm banks. Coral sperm banks.

Example of Coral Spawning: Schmahl/FGBNMS

Through the years, we’ve seen a rapid decline in the amount and genetic diversity of corals with no indication of slowing. Mary Hagedorn, a Smithsonian marine biologist, saw this issue and pioneered the technique of freezing coral sperm. Coral will only reproduce in a period of about a week once per year and in the right conditions, so this process took a lot of work to perfect. Thankfully, Hagedorn was determined, and cryogenic coral sperm banks were created.

Example of a coral spawning.

Credit: Schmahl/FGBNMS

So, how is this possible? Well, it all starts with bringing whole corals into tanks full of seawater. It’s near impossible to collect sperm in the open ocean, so conditions of the coral’s natural habitats are recreated in and around these tanks. When under the right conditions and at the right time, coral will spawn and release many egg-sperm bundles. Once this occurs, bundles are collected, and the eggs and sperm are separated and cleaned. Sperm is then frozen and thawed to test for fertility. The sperm can be kept frozen for years with no lasting damage, and healthy larvae has been successfully produced from long frozen sperm.

Jayne Jenkins Photo Credit Staghorn Spawning

Eggs, however, are much larger than sperm, so they are more difficult to freeze and thaw without damage. Currently, efforts are being made to be able to freeze eggs and possibly coral larvae. It is the hope that once this technique is perfected, we can be able to preserve as much genetic diversity as possible for each coral species.

As much as this is going to preserve coral species, it is a race against time to perfect the techniques and collect samples from each species. Around the world, coral is dying quicker than it can be naturally replenished. Reefs are quickly losing diversity to coral bleaching, and these creatures are essential for many organisms that rely on the shelter and food that coral provides.

"Reefs provide a foundation for sea life, so it’s important to preserve as much diversity as possible in this changing world. Also, healthy coral is way more sexy than bleached coral!"

IYOR International Year of The Reefs

To learn more about coral reefs and their future, follow these links!

Hi, I’m Brynn! I am a student at Utah State University studying fisheries and aquatic sciences. My ultimate goal is to go on to study marine biology, specifically whales. They are such majestic creatures, and I think it’s amazing how something so massive can be so gentle. I hope to research and learn more about them and their behaviors. I’m so excited to be working with Reef Life Restoration because I’m so passionate about the ocean and efforts to save it. I hope to be able to show others how important their work is, and I’m proud to be a part of this kind of organization.

Brynn's Favorite Whale Photo

Brynn Young Marine Biology


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