5:15 PM - 6:45 PM
[MZZ42-P05] Efficient sampling methods for genetic analysis of polymetallic nodules, water just above the sea floor, and sediments
Keywords:polymetallic nodules, water just above the seafloor, genetic analysis, CCZ
In recent years, plans to develop seafloor resources have been underway, but there is concern about the environmental impact on the surrounding areas. One of the key issues in exploration and development is the discussion on the conservation of the marine environment and biodiversity. For example, the International Seabed Authority (ISA), established under the United Nations Convention on the Law of the Sea, recommends for contructors to obtain baseline environmental data, conduct environmental impact assessments, and environmental monitoring. In the Clarion-Clipperton Fracture Zone (CCZ), which is known to be rich in polymetallic nodules, the Global Sea Mineral Resources (GSR) and Bundesanstalt für Geowissenschaften und Rohstoffe (BGR) and others have conducted technical tests of mining viecles and associated detailed monitoring studies (Peacock, 2023), which may be useful for future reference.
Mining of polymetallic nodules is assumed to affect a wide range of deep-sea biospheres due to the loss of nodules and the extensive redeposition of suspended plumes generated by mining activities. For example, nodule fauna are attached to the surface of polymetallic nodules, and there is concern that mining activities could result in a loss of their diversity (e.g., Vanreusel et al., 2016). The importance of the presence of nodules to the abundance, composition and diversity of sediment meiofauna has been investigated to determine the potential impacts of mining, and evaluated the existence and composition of nodule crevice meiofauna (Pape et al., 2021). However, studies on microbial communities are scarce and collection methods have not been established.
The aim of this study is the assessment of the impact of mining on prokaryotes and to first understand their community composition and diversity, sediments, manganese nodules, and water just above the seafloor were sampled in the CCZ in 2019 and samples were fractionated for genetic analysis. The sampling method and detailed procedure for fractionating samples were studied and devised in advance as simply and efficiently. Specifically, sediments were sampled with a multiple corer and water just above the seafloor (70 cm above the bottom) was sampled with a Niskin bottle attached to a frame efficiently. Polymetallic nodules were collected with a multiple corer or box corer, and their surfaces were scraped with a sterilized grater as a simple and clean method. Samples obtained using these methods were used for detailed genetic analysis of prokaryotes in the deep-sea biosphere of the CCZ (Tominaga et. al., 2023).
Mining of polymetallic nodules is assumed to affect a wide range of deep-sea biospheres due to the loss of nodules and the extensive redeposition of suspended plumes generated by mining activities. For example, nodule fauna are attached to the surface of polymetallic nodules, and there is concern that mining activities could result in a loss of their diversity (e.g., Vanreusel et al., 2016). The importance of the presence of nodules to the abundance, composition and diversity of sediment meiofauna has been investigated to determine the potential impacts of mining, and evaluated the existence and composition of nodule crevice meiofauna (Pape et al., 2021). However, studies on microbial communities are scarce and collection methods have not been established.
The aim of this study is the assessment of the impact of mining on prokaryotes and to first understand their community composition and diversity, sediments, manganese nodules, and water just above the seafloor were sampled in the CCZ in 2019 and samples were fractionated for genetic analysis. The sampling method and detailed procedure for fractionating samples were studied and devised in advance as simply and efficiently. Specifically, sediments were sampled with a multiple corer and water just above the seafloor (70 cm above the bottom) was sampled with a Niskin bottle attached to a frame efficiently. Polymetallic nodules were collected with a multiple corer or box corer, and their surfaces were scraped with a sterilized grater as a simple and clean method. Samples obtained using these methods were used for detailed genetic analysis of prokaryotes in the deep-sea biosphere of the CCZ (Tominaga et. al., 2023).