Mediterranean red coral (Corallium rubrum). Credit: Donald Davesne, some rights reserved (CC BY)
Researchers have identified a potential new technique to help calcification in soft corals which involves injecting the coral with a human thyroid hormone.
“We understand a lot about hormones in vertebrates, but much less about hormones in invertebrate animals such as corals,” says Clémence Forin, a PhD student at the Scientific Centre of Monaco.
“We wanted to learn more about how they process hormones to find out how they are involved in the calcification process.”
Coral calcification refers to the process of combining calcium ions and carbonate ions to form calcium carbonate, a strong chemical compound which forms the skeleton and hard parts of coral.
Due to the ocean absorbing excess carbon dioxide emissions, oceans are becoming more acidic which can reduce the concentration of carbonate.
A previous study found that ocean acidification and reduced carbonate can negatively impact the skeletal density of some types of reef-building coral.
Nevertheless, coral calcification is the backbone of reefs and a crucial foundation of a healthy coral ecosystem.
One challenge facing research into the role of hormones in coral has been the lack of established techniques.
However, Forin and her team have developed a new method to accurately monitor corals that have been injected with hormones.
Coral injection protocol. Credit: Clemence Forin (CC BY-NC-ND)
“The major benefits of this injection method are that we can accurately inject the same concentration of hormones each time, and that we can trace where it is going inside the organism,” says Forin.
“We needed to make sure that all the hormones made it to the cells of interest and that soluble hormones wouldn’t be lost in the surrounding seawater.”
Forin and her team screened a number of different human hormones for pro-calcification effects before identifying thyroxine as the prime candidate.
In humans, thyroxine plays a role in metabolism, digestion, muscle function and brain development.
Additionally, thyroxine has been shown in previous studies to have links to skeletal development and bone health.
“We found that thyroxine had a positive effect on the coral’s calcification process,” says Forin, who will present the findings at the Society for Experimental Biology Annual Conference in Antwerp, Belgium on 9 July.
“If the coral is able to process and use the thyroxine, then it means that specific metabolic pathways have been conserved,” says Forin, who adds the findings raise questions about how coral evolved.
“The big question now is how these corals utilise thyroxine in their natural habitat.”