Spanish Institute of Oceanography, Moll de Ponent s/n, 07015 Palma, Spain.
Mar Environ Res. 2011 May;71(4):235-46. doi: 10.1016/j.marenvres.2011.01.008. Epub 2011 Feb 1.
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 (C20:5n-3) and arachidonic acid (C20:4n-6), both abundant in the macroalgal material, and palmitoleic acid (C16:1n-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.
不规则的海胆，如沙钱形海胆（Spatangus purpureus），是重要的生物搅动者，它们有助于自然生物扰动和软沉积物中生物地球化学循环的功能。在巴利阿里群岛的沿海水域，S. purpureus 存在于软红藻床上，可以达到很高的密度。S. purpureus 的饮食未知，特别是分析该群体的胃内容物非常困难；因此，我们分析了性腺的脂肪酸（FA）组成和潜在的食物资源，以评估该物种的营养关系。S. purpureus 性腺的 FA 图谱与潜在营养资源（藻类和沉积物）的 FA 组成非常吻合，并揭示了具有不同可用资源的地点之间的变化。三种多不饱和 FA 主要存在于 S. purpureus 性腺的组成中：二十碳五烯酸（C20:5n-3）和花生四烯酸（C20:4n-6），两者在大型藻类物质中丰富，以及棕榈油酸（C16:1n-7），这是沉积物样品的特征。细菌输入和肉食性摄食的营养标志在底部植被较少的海胆中明显更为丰富。本研究表明，S. purpureus 性腺的 FA 含量是饮食的有用标志，因为谱的差异反映了碎屑组成的变化。本研究的结果表明，该物种具有杂食性摄食行为；然而，结合可用的丰度数据，结果表明，在藻类床内发现的植物碎屑是该物种的重要碳源。
