Unveiling the Chemical Secrets of Coral Reefs and Insights into Marine Health

What species exist on this coral reef, and how healthy are they? Chemical cues released by marine organisms might contain that information. However, invisible compounds form a complicated “soup” in underwater settings that scientists struggle to understand.

Researchers in the American Chemical Society’s Journal of Proteome Research have now revealed how to extract and identify these indicator molecules in seawater. They discovered previously unknown metabolites on reefs, including three that might represent various reef organisms.

Coral reef plants and animals discharge a wide range of chemicals into the surrounding water, from intricate macromolecules to single amino acids. Scientists must concentrate the chemicals and separate them from the salty broth to create water samples for study. This will allow them to discover which ones could be used to monitor the health of a coral reef and identify its inhabitants.

They mainly concentrate and gather these dissolved substances from seawater on sticky membranes. Nevertheless, this approach overlooks many significant sulfur, oxygen, and nitrogen-containing chemicals produced by marine life.

These metabolites are incredibly rare in seawater and do not bind effectively to the materials that make up the membrane. To get around these difficulties, researchers at Woods Hole Oceanographic Institution Brianna Garcia, Amy Apprill, Elizabeth Kujawinski, and associates tested a method that changed the dissolved metabolites before they were extracted from seawater into a form that is compatible with membrane materials, enabling them to be concentrated and examined.

Five coral reefs near the US Virgin Islands provided water samples that the researchers collected and filtered. Then, they attached a benzoyl functional group to dissolved metabolites that included alcohol and amines by a sequence of processes.

Subsequently, the group isolated the altered metabolites from the specimens and evaluated their makeup and amounts using liquid chromatography-mass spectrometry.

Using this novel approach, the researchers discovered 23 metabolites—amino acids, amines, pyrimidine nucleosides, and organosulfonic acids—that had not been discovered in the vicinity of coral reefs by earlier studies and are crucial to photosynthesis and organism growth. Following their data analysis, the researchers discovered that:

• The metabolite compositions were most affected by the presence of crustose coralline algae, macroalgae, and diseased coral
• Certain substances, such as the organosulfonic acid known as DHPS, were continuously found in large concentrations across all sites, indicating the existence of coral and related species
• The researchers attributed the large variability in levels of three metabolites (homoserine betaine, tryptophan, and γ-aminobutryic acid) among the five reefs to variances in marine habitats and organisms

According to the researchers, this study effectively illustrates how to gather ecologically significant compounds in coral reef ecosystems that were previously disregarded. With this knowledge, the ecosystems might be monitored for effects of disease activity, natural disturbances, and climate change.