Abstract
The intra-skeletal fatty acid concentration and composition of four Mediterranean coral species, namely Cladocora caespitosa, Balanophyllia europaea, Astroides calycularis and Leptopsammia pruvoti, were examined in young and old individuals living in three different locations of the Mediterranean Sea. These species are characterized by diverse levels of organization (solitary or colonial) and trophic strategies (symbiotic or non-symbiotic). Fatty acids have manifold fundamental roles comprehensive of membrane structure fluidity, cell signaling and energy storage. For all species, except for B. europaea, the intra-skeletal fatty acid concentration was significantly higher in young individuals than in old ones. Moreover, fatty acid concentration was higher in colonial corals than in solitary ones and in the symbiotic corals compared to non-symbiotic ones. Analysis by gas chromatography-mass spectrometry (GC-MS) revealed that palmitic acid (16:0) was the most abundant fatty acid, followed by stearic (18:0) in order of concentration. Oleic acid (18:1) was detected as the third main component only in skeletons from symbiotic corals. These results suggest that, in the limits of the studied species, intra-skeletal fatty acid composition and concentration may be used for specific cases as a proxy of level of organization and trophic strategy, and eventually coral age.
Highlights
Lipids are important energy reserves, mainly stored in the animal tissue as wax esters and triglycerides, or in the membranes as sterols and polyunsaturated fatty acids
As reported in previous studies[29, 30], these three locations are characterized by different average annual sea surface temperatures (SST) and solar radiation (SR) values, with an increase of almost 2 °C in SST and 44 W m−2 in SR going from CL to Pantelleria Island (PN)
A laboratory developed procedure allowing the detection of microgram of fatty acids (FAs) was applied to overcome the difficulties due to the low concentration of intra-skeletal FAs
Summary
Lipids are important energy reserves, mainly stored in the animal tissue as wax esters and triglycerides, or in the membranes as sterols and polyunsaturated fatty acids. Since lipid composition is often specific to particular groups of organisms[1], the analysis of lipids, such as fatty acids (FAs), gives useful information on their autotrophic or heterotrophic origin[2]. FAs structure and production are dependent upon lipogenesis pathways and associated enzymes, which change among organisms. Excess fixed carbon is stored in the host tissue as lipids, representing significant energy reserves[4]. Polar lipids and sterols are the structural basis of symbiotic zooxanthellae (i.e., endosymbiotic dinoflagellates of the Symbiodinium group8) cell membranes, while triacylglycerols, wax, and sterol esters serve as storage lipids and determine the energy balance of the animal[4].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
