[MIS08-P06] Distribution of eukaryotic DNA in global deep subseafloor sediments: Potential for reconstruction of paleo-ecosystems
Keywords:IODP, sediment, environmental DNA
In this study, we investigated the distribution of 18S rRNA gene in the remaining palaeoenvironmental DNA in millions of years old sediment. We attempted to amplify 18S rRNA gene fragments using extracted DNA from 300 subseafloor sediment samples globally collected from the past ocean drilling projects. DNA was extracted by hot-alkaline and commercial kit-based methods, resulting in more than 600 DNA extracts. PCR using domain specific primers successfully amplified 18S rRNA gene fragments from 175 DNA extracts that are mainly from sediments down to 100 mbsf. Using those amplicon, iTag sequencing was performed to characterize eukaryotic (palaeo-) biodiversity. As a result, fungal DNA was abundant in the obtained sequence libraries, nevertheless those fungi are known to be revivable or not. Algae related 18S rRNA sequences including Ochrophyta, Dinoflagellata, and Chlorophyta are also prevalent in all samples though the relative abundances decreased with depth. These results suggested that palaeoenvironmental DNA was preserved in deep subseafloor sediments. In this presentation, we will discuss the correlation between the eukaryotic diversity and sedimentological and/or palaeoenvironmental setting, and also the potential of palaeoenvironmental DNA for reconstructing paleoecosystem.