ABSTRACT The current study investigated diatom communities on juvenile green turtles foraging in neritic habitats around five Iranian islands. The primary objectives were to (1) compare species composition, growth form structure, and abundance of diatom communities associated with sea turtles foraging within the restricted boundaries of local feeding pastures, and (2) assess the level of uniqueness of the epizoic diatom flora in comparison with biofilms growing on floating debris. All observations and diatom counts were performed using scanning electron microscopy. The effect of the sampling location was apparent among sea turtle samples and reflected in significantly different cell densities. Diatom abundances were significantly higher on sea turtles (758–1836 cells mm−2) than on floating debris samples (9–189 cells mm−2). Epizoic diatom communities were composed of 20 diatom taxa and dominated by erect forms belonging to the so-called ‘marine gomphonemoids’, Chelonicola and Poulinea, previously reported on sea turtles from other geographical regions. The diatom flora found on floating debris was composed of 21 taxa. Only four taxa, Amphora cf. bigibba, Cocconeis cf. neothumensis var. marina, Psammodictyon constrictum, and Tabularia affinis, were recorded from both sea turtles and floating debris samples, and none of these exceeded 4% of the average relative abundance on the sea turtle carapaces. The study reveals a clear substratum preference in sea turtle-associated diatoms, with no evidence for species turnover across the investigated region over different sampling seasons, thus confirming previous speculations that sea turtle diatom communities would show a high level of uniqueness and stability.

中文翻译：

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波斯湾（西亚）海龟上的硅藻和漂浮物

摘要 目前的研究调查了在伊朗五个岛屿周围的浅海栖息地觅食的幼年绿海龟的硅藻群落。主要目标是 (1) 比较物种组成、生长形式结构和与在当地饲养牧场限制边界内觅食的海龟相关的硅藻群落的丰度，以及 (2) 评估在与生长在漂浮碎片上的生物膜相比。所有观察和硅藻计数均使用扫描电子显微镜进行。采样位置的影响在海龟样本中很明显，并反映在显着不同的细胞密度上。海龟（758-1836 个细胞 mm-2）的硅藻丰度显着高于漂浮碎片样本（9-189 个细胞 mm-2）。生代硅藻群落由 20 个硅藻类群组成，并以属于所谓的“海洋 gomphonemoids”、 Chelonicola 和 Poulinea 的直立形式为主，之前报道过来自其他地理区域的海龟。在漂浮的碎片上发现的硅藻群由 21 个分类群组成。只有四个分类群，Amphora cf。bigibba, Cocconeis cf. Neothumensis 变种 marina、Psammodictyon constrictum 和 Tabularia affinis 均从海龟和漂浮碎片样本中记录到，并且这些都没有超过海龟甲壳平均相对丰度的 4%。该研究揭示了海龟相关硅藻的明显基质偏好，没有证据表明不同采样季节的整个调查区域的物种更替，