Skip to content. | Skip to navigation

Personal tools
Log in
Sections
You are here: Home Blog Acroporas "live" much longer than previously thought

Acroporas "live" much longer than previously thought

By Leonard Ho - Posted Dec 07, 2016 09:00 AM
A study has found the oldest genotypes of Acropora palmata (elkhorn corals) are over 5,000 years old. Put another way: reefkeepers can still be trading the same frag genes of today's "designer corals" many millennia from now.
Acroporas "live" much longer than previously thought

Acropora palmata is listed as threatened under the U.S. Endangered Species Act. Image: William Precht/Dial Cordy and Associates, Inc.

Corals much older than previously thought, study finds

 

Coral genotypes can survive for thousands of years, possibly making them the longest-lived animals in the world, according to researchers at Penn State, the National Marine Fisheries Service and Dial Cordy & Associates.

The team recently determined the ages of elkhorn corals -- Acropora palmata -- in Florida and the Caribbean and estimated the oldest genotypes to be over 5,000 years old. The results are useful for understanding how corals will respond to current and future environmental change.

"Our study shows, on the one hand, that some Acropora palmata genotypes have been around for a long time and have survived many environmental changes, including sea-level changes, storms, sedimentation events and so on," said Iliana Baums, associate professor of biology, Penn State. "This is good news because it indicates that they can be very resilient. On the other hand, the species we studied is now listed as threatened under the U.S. Endangered Species Act because it has suffered such sharp population declines, indicating that there are limits to how much change even these very resilient corals can handle."

According to Baums, many people mistake corals for plants or even non-living rocks, but corals actually consist of colonies of individual invertebrate animals living symbiotically with photosynthetic algae.

"Previously, corals have been aged by investigating the skeletons of the colonies or the sizes of the colonies," she said. "For example, bigger colonies were thought to be older. However many coral species reproduce via fragmentation, in which small pieces break off from large colonies. These pieces look like young corals because they are small, but their genomes are just as old as the big colony from which they broke. Similarly, the big colonies appear younger than their true age because they became smaller during the process of fragmentation."

Now, for the first time, Baums and her colleagues have used a genetic approach to estimate the ages of corals. The method determines when the egg and the sperm originally met to form the genome of the coral colonies. The researchers then tracked the number of mutations that accumulated in the genome since that time. Because mutations tend to arise at a relatively constant rate, the researchers were able to estimate an approximate age in calendar years of the coral genomes in their study.

The results, which appear in print in the November 2016 issue of the journal Molecular Ecology, suggest that some Acropora palmata genomes have been around for over 5,000 years.

"This was surprising, as previously, only cold-water corals were found to be older than 1,000 years," said Baums. "Knowing the age of individuals in a population is important for understanding their population history and whether the population is increasing or decreasing. It is especially important when the population under study is threatened.

 


via Penn State University

Journal Reference:

  1. M. K. Devlin-Durante, M. W. Miller, W. F. Precht, I. B. Baums. How old are you? Genet age estimates in a clonal animal. Molecular Ecology, 2016; 25 (22): 5628 DOI: 10.1111/mec.13865

Author: Leonard Ho
Location: Southern California

I'm a passionate aquarist of over 30 years, a coral reef lover, and the blog editor for Advanced Aquarist. While aquarium gadgets interest me, it's really livestock (especially fish), artistry of aquariums, and "method behind the madness" processes that captivate my attention.

Website: http://www.advancedaquarist.com.

Document Actions
blog comments powered by Disqus

blog_sm.jpg

Contribute to our blogs!


Do you have news or discussion topics you want to see blogged?  Let us know!

 

ADVANCED AQUARIST