Trophic ecology of the sea urchin Spatangus purpureus elucidated from gonad fatty acids composition analysis

• Published in: Marine environmental research Vol. 71; no. 4; pp. 235 - 246
• Main Authors: Barberá, C., Fernández-Jover, D., López Jiménez, J.A., González Silvera, D., Hinz, H., Moranta, J.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2011; Elsevier
• Subjects: Algae; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Bacteria; Biological and medical sciences; Bioturbation; Carbon; Deposit feeder; Detritus; Diet; Diet - statistics & numerical data; Echinodermata; Echinoidea; Ecosystem; Environmental Monitoring - methods; Fatty acids; Fatty Acids - metabolism; Feeding; Food Chain; Fundamental and applied biological sciences. Psychology; Gonads; Gonads - metabolism; Invertebrates; Marine; Mediterranean Sea; Rhodophyta - growth & development; Sandy bottoms; Sea urchins; Sea Urchins - metabolism; Sea water ecosystems; Sediment; Sediments; Soft red algae; Spatangus purpureus; Synecology; Vegetation; Mediterranean Sea; MED, Spain, Balearic Is; Bioturbation; Sea urchins; Sediment; Diet; Deposit feeder; Detritus; Soft red algae; Fatty acids; Mediterranean sea; Sandy bottoms; Feeding; Rhodophyta; Echinodermata; Algae; Genital system; Lipids; Trophic relation; Ecology; Sediments; Marine environment; Gonad; Echinoidea; Invertebrata; Sea urchin
• ISSN: 0141-1136; 1879-0291
• DOI: 10.1016/j.marenvres.2011.01.008

Irregular sea urchins such as the spatangoid Spatangus purpureus are important bioturbators that contribute to natural biogenic disturbance and the functioning of biogeochemical cycles in soft sediments. In the coastal waters of the Balearic Islands S. purpureus occurs in soft red algal beds, and can reach high densities. The diet of S. purpureus is unknown and it is particularly difficult to analyze the stomach contents of this group; therefore, we analyzed the fatty acid (FA) composition of the gonads and potential food resources in order to assess the trophic relationships of this species. The FA profiles of the gonads of S. purpureus agree well with the FA composition of the potential trophic resources (algae and sediment) and reveals changes between localities with different available resources. Three polyunsaturated FAs mainly contributes in the composition in the S. purpureus gonads: eicosapentaenoic acid (C20:5 n-3) and arachidonic acid (C20:4 n-6), both abundant in the macroalgal material, and palmitoleic acid (C16:1 n-7), which is characteristic of sediment samples. Trophic markers of bacterial input and carnivorous feeding were significantly more abundant in sea urchins caught on bottoms with less vegetation. The current study demonstrates that the FA content of S. purpureus gonads is a useful marker of diet, as differences in the profiles reflected the variations in detritus composition. The results of this study show that this species has omnivorous feeding behavior; however, viewed in conjunction with available abundance data the results suggest that phytodetritus found within algal beds is an important carbon source for this species. ► We analyzed the fatty acid (FA) composition of the gonads and potential food resources (main algae and sediment samples) in order to assess the trophic relationships of this species. Three polyunsaturated FAs were the most abundant in the gonads of S. purpureus: eicosapentaenoic acid (C20:5 n-3) and arachidonic acid (C20:4 n-6), both abundant in the macroalgal material, and palmitoleic acid (C16:1 n-7), which is characteristic of sediment samples. ► The FA composition of sea urchin gonads changes in relation to sampling location (i.e. available resources) and the gonadal development. ► Biomarkers of bacterial input and carnivorous feeding were more elevated in sea urchins caught on bottoms with less vegetation. ► The results of this study highlight the omnivorous feeding behavior of this species and suggest that phytodetritus found within algae beds is an important carbon source for this species.