Analytical pyrolysis-based study on intra-skeletal organic matrices from Mediterranean corals

Area of Science:

• Marine Biology
• Biochemistry
• Geochemistry

Background:

• The intra-skeletal organic matrix (OM) plays a crucial role in coral biomineralization.
• Understanding OM composition is key to deciphering coral skeletal structure and formation.
• Previous characterizations often lacked detailed molecular insights into OM precursors.

Purpose of the Study:

• To characterize the organic matrix (OM) of four Mediterranean hard coral species.
• To investigate potential correlations between OM composition, coral growth form, and trophic strategy.
• To identify key macromolecules governing coral biomineralization.

Main Methods:

• Off-line analytical pyrolysis coupled with gas chromatography–mass spectroscopy (GC–MS).
• Infrared spectroscopy and amino acid analysis.
• Chemometric analysis including principal component analysis (PCA) and clustering analysis.

Main Results:

• Pyrolysis identified lipid, protein (including novel diketopiperazine markers), and polysaccharide precursors in coral OM.
• All studied coral species exhibited a low protein content relative to lipids and polysaccharides.
• Minimal compositional diversity was observed across species, suggesting conserved OM structure and composition.

Conclusions:

• Coral biomineralization appears to be governed by similar macromolecules and mechanisms across diverse species.
• OM composition and skeletal organization are largely independent of coral growth form and ecological strategy.
• The findings highlight conserved molecular underpinnings of coral skeletal formation.