Meiofaunal diversity at a seamount in the pacific ocean: A comprehensive study using environmental DNA and RNA

Authors：Tomo Kitahashi; Sachie Sugime; Kentaro Inomata; Miyuki Nishijima; Shogo Kato; Hiroyuki Yamamoto

Source：Deep-Sea Research Part I: Oceanographic Research Papers , 2020, 103253.

DOI：10.1016/j.dsr.2020.103253

• Seamount
• Meiofauna
• Metabarcoding analysis
• eDNA
• eRNA

In deep-sea environments, which have low densities of large benthic animals, meiofauna are a useful indicator of biodiversity. However, in low-latitudes and in low-productivity areas, meiofaunal density is low, but is higher than that of megafaunal or macrofaunal density. Therefore, it is difficult to collect a sufficient number of specimens for statistical analysis. In addition, because faunal classification has been based on conventional microscopic observations, the use of meiofauna to estimate biodiversity in deep-sea environments is time-consuming. However, metabarcoding analyses focused on environmental DNA (eDNA) or RNA (eRNA) have recently been used to examine deep-sea eukaryotic diversity and communities. Here, we examined meiofaunal assemblages using microscopic, eDNA-, and eRNA-based methods at Xufu Guyot (JA06 Seamount), off the southeastern coast of Minami-Torishima Island in the North Pacific Ocean. Microscopic analysis failed to detect a significant difference in diversity or community structure between the seamount terrace and base. This was likely because of the low abundance of meiofauna, which was caused by the low surface productivity at the study area. However, eDNA/eRNA-based metabarcoding analyses revealed spatial variations in diversity and community structures within a single seamount. Therefore, metabarcoding analysis might be useful to elucidate meiofaunal assemblages in areas with low productivity and low faunal density.

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