Unit for Environmental Sciences and Management, School of Biological Sciences, North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
South African Institute for Aquatic Biodiversity (SAIAB), Private Bag 1015, Grahamstown, 6140, South Africa.
Microb Ecol. 2017 Nov;74(4):969-978. doi: 10.1007/s00248-017-0987-x. Epub 2017 May 6.
The first reports of diatoms growing on marine mammals date back to the early 1900s. However, only recently has direct evidence been provided for similar associations between diatoms and sea turtles. We present a comparison of diatom communities inhabiting carapaces of green turtles Chelonia mydas sampled at two remote sites located within the Indian (Iran) and Atlantic (Costa Rica) Ocean basins. Diatom observations and counts were carried out using scanning electron microscopy. Techniques involving critical point drying enabled observations of diatoms and other microepibionts still attached to sea turtle carapace and revealed specific aspects of the epizoic community structure. Species-poor, well-developed diatom communities were found on all examined sea turtles. Significant differences between the two host sea turtle populations were observed in terms of diatom abundance and their community structure (including growth form structure). A total of 12 and 22 diatom taxa were found from sea turtles in Iran and Costa Rica, respectively, and eight of these species belonging to Amphora, Chelonicola, Cocconeis, Navicula, Nitzschia and Poulinea genera were observed in samples from both locations. Potential mechanisms of diatom dispersal and the influence of the external environment, sea turtle behaviour, its life stage, and foraging and breeding habitats, as well as epibiotic bacterial flora on epizoic communities, are discussed.
最早关于硅藻在海洋哺乳动物上生长的报道可以追溯到 20 世纪初。然而，直到最近才提供了硅藻与海龟之间存在类似联系的直接证据。我们比较了在印度（伊朗）和大西洋（哥斯达黎加）洋盆两个偏远地点采集的绿海龟（Chelonia mydas）壳上的硅藻群落。使用扫描电子显微镜进行了硅藻观察和计数。临界点干燥技术能够观察到仍然附着在海龟壳上的硅藻和其他微附生物，并揭示了附生群落结构的特定方面。在所有检查过的海龟上都发现了物种较少但发育良好的硅藻群落。在硅藻丰度及其群落结构（包括生长形态结构）方面，两个宿主海龟种群之间存在显著差异。从伊朗和哥斯达黎加的海龟中分别发现了 12 和 22 种硅藻，其中 8 种属于双菱藻属、Chelonicola 属、Cocconeis 属、舟形藻属、菱形藻属和 Poulinea 属，这些物种在两个地点的样本中均有发现。讨论了硅藻传播的潜在机制以及外部环境、海龟行为、其生命阶段、觅食和繁殖栖息地以及附生细菌菌群对附生群落的影响。
