Chemotaxonomy of reef building corals (family: Acroporidae) via fatty acid biomarkers

Fatty Acids (FAs) are the biochemical compounds used as chemotaxonomic biomarkers for the systematic grouping of cnidarians. This study presents the chemotaxonomy of hard coral, particularly from the family Acroporidae (Anacropora [ANA], Montipora [MON], Astreopora [AST], and Acropora [ACP]) by applying multivariate analysis of FA composition matrix, of polyunsaturated FAs (PUFAs) to make a distinction among coral genera within the family. 18:4n-3, 18:3n-6, 20:5n-3, 20:4n-6, 22:6n-3, and 22:4n-6 have been identified as the characteristic FAs to differentiate between coral genera from the family Acroporidae. The classification of ANA, AST, and ACP was extensively affected by the distribution of the 18:4n-3, 20:5n-3, 22:6n-3, and 20:4n-6 FAs, while MON differed from the others with distinctive 22:4n-6 and 18:3n-6 compositions. The PUFAs 18:4n-3, 18:3n-6, and 20:5n-3 were then correlated with the Symbiodiniaceae (SYMD) density, thus rendering them a possible biomarker for symbiotic algae. The study findings indicate that genera-specific compositions can be characterised from the different PUFA content within the cnidarian through multivariate analyses such as permutational analysis of variance (PERMANOVA), similarity percentage (SIMPER), and canonical analysis of principal component (CAP). The FA composition and distribution are used for further classification of the hard corals to the lowest taxonomic level possible.