Reconstruction of the Eukaryotic Communities in Beppu Bay Over the Past 50 Years Based on Sedimentary DNA Barcoding. Issue 6 (2nd June 2022)

• Record Type: Journal Article
• Authors: Segawa, Yudai; Yamamoto, Masanobu; Kuwae, Michinobu; Moriya, Kazuyoshi; Suzuki, Hitoshi; Suzuki, Koji
• Is Part Of: Journal of geophysical research. Volume 127:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-02
• Subjects: DNA barcoding -- sedaDNA -- eukaryotic communities -- nutrient availability -- Beppu Bay -- the Anthropocene; Geobiology -- Periodicals; Biogeochemistry -- Periodicals; Biotic communities -- Periodicals; Geophysics -- Periodicals; 577.14
• DOI: 10.1029/2022JG006825
• Languages: English
• ISSNs: 2169-8953

Abstract

Abstract: Comprehensive reconstruction of changes in eukaryotic communities in the recent past is useful for determining the response of the local ecosystems to global changes during the Anthropocene. We used DNA barcoding technology to reconstruct the marine eukaryotic communities of Beppu Bay, the Seto Inland Sea, Japan, over the past 50 years based on a short sediment core. Highly vulnerable DNA fragments were preserved in the sediments, possibly due to seasonally euxinic conditions. Analysis of the 18S rRNA V9 gene region indicated the temporal variability in eukaryotic communities, which consisted mainly of dinoflagellates and diatoms, in response to changes in the nutrient regime. The dominant species in the dinoflagellate genus Alexandrium changed as the water temperature increased. In addition, enhanced contributions by terrestrial plants and mosses were detected in flood sediments. Our results suggest that DNA fragments can be used as a proxy for the paleoenvironmental and paleoecological conditions in Beppu Bay. Plain Language Summary: Information about past environmental changes is important for understanding the present and future environments. In this study, we used the DNA preserved in sea‐bottom sediments in Beppu Bay to reconstruct phytoplankton communities over the past 50 years. The DNA in sediments contains comprehensive information about past phytoplankton communities, but it is vulnerable to degradation under normal conditions. However, the sediments from Beppu Bay yielded significant amounts of DNA, possibly because seasonally reducing conditions suppressed the degradation of DNA. We found that phytoplankton communities changed in response to changes in nutrient availability. Further, the genes of terrestrial plants and mosses were more abundant in flood sediments. Our results suggest that the DNA fragments can be used as a proxy of the paleoenvironmental and paleoecological conditions in Beppu Bay. Key Points: DNA barcoding technology was used to reconstruct the marine eukaryotic communities in Beppu Bay, Japan Highly vulnerable DNA fragments were preserved in the sediments, possibly due to seasonally euxinic conditions Eukaryotic communities have shifted over recent decades in response to changes in nutrient availability