Spatio-temporal variability of secondary metabolites in the invasive coral Tubastraea coccinea

Abstract

Tubastraea coccinea is a coral species originally described for the Pacific Ocean. It is widely distributed throughout the Brazilian coast and in several other Atlantic areas. Its widespread occurrence is presumably facilitated by its production of secondary metabolites with defensive action against predators and competitors. This study evaluated the spatial and temporal variability in the chemical profile of T. coccinea in Arraial do Cabo Bay, Southeastern Brazil, using GC/MS analysis. We also compared the profiles between sites/seasons with non-Metric Multidimensional Scaling (n-MDS) and Principal Component Analysis (PCA). Our results showed that the total metabolite (extract yield) decreased in winter and increased significantly in spring. Sterols and fatty acid esters were the main compounds identified in the four T. coccinea populations. The extracts differed qualitatively and quantitatively between the four T. coccinea populations. Winter samples had the highest lipid contents, although they showed the lowest contents of total metabolites. The highest values of extract yields were obtained for the spring samples, while in fall it did not show significant diferences. The n-MDS and PCA also revealed differences in the chemical profiles between fall, winter, and spring samples. However, the observed chemical variability did not allow a clear distinction between the T. coccinea populations. It did reflect similar environmental conditions at sites close to the ocean and sheltered areas. This invasive coral has already adapted itself to the presumed dynamics of interactions with competitors and consumers.