Sperm Banks: Now for Coral

The endangered “elkhorn coral,” was formerly the dominant reef-producing species in the Caribbean. Over the course of 30 years, 80% of corals in the Caribbean have been decimated due to coral diseases caused by a deterioration of water quality from human activity. An increase in ocean acidity has led to the corrosion of coral reefs. In Gambino’s article, she informs us of the grim reality: “About one-third of all corals are in threat of extinction, and some coral experts say that we could lose reefs as we know them by 2050.”

Coral only spawns one day a year, three days after a full moon. They release a chemical into the water that alerts nearby colonies to begin spawning. “For two to four nights, each individual coral polyp on a colony releases a bundle of eggs and sperm into the water column. (Gambino)” These bundles float to the surface and mix with eggs and sperm from other colonies to fertilize one another. In the case of biologists who collect these gametes for sperm banks, they place fine nets over individual corals that rise to the surface where the samples are then collected and examined for viability before being frozen.

A marine biologist from the Smithsonian Conservation Biology Institute, Mary Hagedorn began the first “frozen repositories of coral sperm and embryonic cells,” at the Hawaii Institute of Marine Biology. The “sperm banks” contain samples from elkhorn as well as Hawaiian mushroom coral. In an article by Tim Wall, Hagedorn said, “It is crucial that we begin ex situ conservation on coral reefs while their genetic diversity is still high.” While she hopes that they never have to use the banks, the coral sperm and embryonic cells could be thawed out to restore diversity to dying coral populations. Hagedorn hopes to expand her bank to include gametes from rice coral, which is a Hawaiian species at risk for disease and bleaching. Besides the application of cryopreservation toward coral sperm and embryonic cells, she is working on developing a method of freezing small fragments of coral to utilize its ability to reproduce asexually as well (Gambino).

Sperm banks for coral would aid in the protection of their genetic diversity and prevent further extinction. Coral reefs are also places that one-quarter of marine species call home. In this way, the preservation of coral reefs would not only benefit the reef species, but also prevent the habitat degradation of many other marine species. Reefs are also very beneficial to humans as well, since “they protect shorelines from hurricanes and tsunamis and are a source of potential biopharmaceuticals.”

Gambino, Megan. “Saving Coral…Through Sperm Banks?” Smithsonian. Smithsonian Institution., 15 Sept. 2011. Web. 21 October 2011.

Wall, Tim. “Banking Coral Sperm.” Discovery News. Discovery Communications., 19 May 2011. Web. 21 October 2011.