Do Corals Change How They Smell When They are Under Stress?
- Jan 07, 2022
- Anshika Mishra
- 199 0 0
Did you know that coral smells can tell us a lot about their health? As it turns out, it can!
By measuring the quantity and mic of chemicals released by coral, we might be able to find out much stress the coral is under.
In this article, we are putting forth all the information about coral smells and how they can be an indicator of the stress your coral is enduring:
However, before we dive into the science of these volatile compounds, let's address the elephant in the room. Copper casts a long shadow in coral- once it is into their tissues, the damage is both cumulative and long-lasting.
Volatile Compounds
A paper titled Heat stress decreases the density abundance and functional potential of coral gas emissions was published in global change biology in October 2020. The team is studying volatile compounds released by corals and how those might change based on the stress level of the coral.
Now, corals release a lot of compounds. In particular, dimethylsulfoniopropionate is removed in such quantities that it can even change the weather. In the air, we can even smell these compounds. You know what Acrapora smells like.
But, just because they are underwater, it doesn't mean that these same compounds are not still being released. So, this is one of the first studies to explore these compounds, how much is produced, and what they actually might be used for in corals.
The Experiment
They measure the chemicals released by corals kept in an aquarium at about 27-5 degrees Celcius. And, then it is estimated again after slowly raising the temperature degree by degree to 32 degrees Celcius.
Studying two corals, a Pocillopra and an Acropora, they found a total of 79 biogenic volatile organic compounds in the Acropora and 76 from the Pacillopora. Nineteen of those compounds were found in both corals, including aldehydes, alkanes, aromatic hydrocarbon, carboxylic acid, ester, and halogenated hydrocarbons.
Results
Heat stress is significantly reduced the volatile chemicals produced by the corals. For example, of those 19 compounds that both corals produced, heat stress led to 58% less of them being released.
- The Acropora released only 42% fewer chemicals - only 46 in total
- The Pocillopora saw a similar reduction, by 62%, to only 29 compounds
Some compounds were only found in stressed corals. Five chemicals were detected only after being subjected the coral to heat stress. This is interesting because we know that some pathogenic bacteria use those compounds to target stressed corals, corals that are less likely to fight off an infection.
Testing Coral's Stress Level
It would be great if we could test some of these compounds, a test that would tell us the stress level of our corals. We are already doing advanced testing on our aquarium water - an ICP test was once crazy to think of having down at a hobbyist level. Yet here, we can send water to numerous companies and have the testing done.
Maybe one day, we will have the same kind of test, but it will be measuring the stress level of the tank overall, based on the quantity and what chemicals are found in the sample.
I hope you enjoyed the topic. Happy Reefing!
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