In recent years, biofilm-forming diatoms have received increased attention as sea turtle epibionts. However, most of the research has focused on carapace-associated taxa and communities, while less is known about diatoms growing on sea turtle skin. The current study investigated diatom diversity on the skin of loggerhead sea turtle heads detached from the carcasses found along the Adriatic coast between 1995 and 2004 and stored frozen for a prolonged period of time. By using both light and scanning electron microscopy we have found diatom frustules in 7 out of 14 analysed sea turtle samples. Altogether, 113 diatom taxa were recorded, with a minimum of seven and a maximum of 35 taxa per sample. Eight taxa, Achnanthes elongata, Berkeleya cf. fennica, Chelonicola sp., Licmophora hyalina, Nagumoea sp., Navicula sp., Nitzschia cf. lanceolata, and Poulinea lepidochelicola exceeded 5% of relative abundance in any one sample. The presumably obligately epizoic diatom taxa, A. elongata, Chelonicola sp., and P. lepidochelicola, dominated in six loggerhead samples, contributing up to 97.1% of the total diatom abundance. These observations suggest that on the sea turtle skin highly specialised taxa gain even greater ecological advantage and dominance over the co-occurring benthic forms than in the carapace biofilms. The suitability of frozen sea turtle skin specimens for diatom analysis and limitations of this approach are discussed.

中文翻译：

---

冷冻历史性黑海龟标本皮肤上的硅藻多样性

近年来，生物膜形成硅藻作为海龟的表皮生物越来越受到关注。但是，大多数研究都集中在与甲壳相关的类群和群落上，而对在海龟皮肤上生长的硅藻的了解却很少。目前的研究调查了1995年至2004年间从亚得里亚海沿岸发现的体上分离出来的海龟头部皮肤上的硅藻多样性，并将其冷冻保存了很长一段时间。通过使用光学显微镜和扫描电子显微镜，我们在14个分析的海龟样本中的7个中发现了硅藻壳。总共记录了113个硅藻类群，每个样品最少7个，最大35个类群。八个类群，曲壳藻泡桐，Berkeleya参见 fennica，Chelonicola sp。，Licmophora hyalina，Nagumoea sp。，Navicula sp。，Nitzschia cf. 在任何一个样品中，披针叶和鳞翅目对虾的相对丰度都超过了5％。大概专为偶生的硅藻类群，长曲霉（A. elongata），Chelonicola sp。和鳞翅目P. lepidochelicola，在六个头样品中占主导地位，占硅藻总含量的97.1％。这些观察结果表明，与甲壳生物膜相比，高度共生的底栖生物在海龟皮肤上比共生底栖生物获得更大的生态优势和优势。讨论了冷冻海龟皮肤标本对硅藻分析的适用性以及该方法的局限性。