Microbial cell distribution in the Guaymas Basin subseafloor biosphere, a young marginal rift basin with rich organics and steep temperature gradient
- 1JAMSTEC, Kochi, Japan (morono@jamstec.go.jp)
- 2Department of Marine Sciences, University of North Carolina at Chapel Hill, USA
- 3Department of Earth Sciences, University of Southern California, USA
- 4Department of Geology and Geophysics, Woods Hole Oceanographic Institution, USA
- 5Department of Earth System Science, Stanford University, USA
- 6Section Geomicrobiology, German Research Centre for Geosciences (GFZ Helmholtz Centre Potsdam), Germany
- 7IFREMER, Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, France
- 8Department of Geosciences University of Bremen, Bremen, Germany
- *A full list of authors appears at the end of the abstract
Guaymas Basin is a young marginal rift basin in the Gulf of California characterized by active seafloor spreading and rapid sediment deposition, including organic-rich sediments derived from highly productive overlying waters and terrigenous sediments from nearby continental margins. The combination of active seafloor spreading and rapid sedimentation within a narrow basin results in a dynamic environment where linked physical, chemical, and biological processes regulate the cycling of sedimentary carbon and other elements.
During IODP Expedition 385, eight sites were drilled on the flanking regions and in the northern axial graben of Guaymas Basin, recovering organic-rich sediments with sill intrusions. Those cored samples were examined for their microbial cell abundance in a highly sensitive manner by density-gradient cell separation at the super clean room of Kochi Core Center, Japan, followed by direct counting on fluorescence microscopy. Cell abundance in surficial seafloor sediment (~109 cells/cm3) was roughly 1000 times higher than the bottom seawater (~106 cells/cm3) and gradually decreased with increasing depth and temperature. In contrast to the cell abundance profile observed at Nankai Trough (IODP Exp. 370), the gradual decrease of cell abundance was observed up to around 75ºC, and we detected microbial cells even at hot horizons above 100ºC. The existence of smaller size of microbial cells was uniquely found in this region of subseafloor.
We will present the overview of the microbial cell distribution in the Guaymas Basin and discuss its relation to the current and past environmental conditions, e.g., temperature and sill-intrusion, etc.
Andreas P. Teske; Daniel Lizarralde; Tobias W. Höfig; Ivano W. Aiello; Janine L. Ash; Diana P. Bojanova; Martine Buatier; Virginia P. Edgcomb; Christophe Y. Galerne; Swanne Gontharet; Verena B. Heuer; Shijun Jiang; Myriam A.C. Kars; Ji-Hoon Kim; Louise M.T. Koornneef; Kathleen M. Marsaglia; Nicolette R. Meyer; Yuki Morono; Raquel Negrete-Aranda; Florian Neumann; Lucie C. Pastor; Manet Peña-Salinas; Ligia L. Pérez Cruz; Lihua Ran; Armelle Riboulleau; John A. Sarao; Florian Schubert; S. Khogenkumar Singh; Joann M. Stock; Laurent M.A.A. Toffin; Wei Xie; Toshiro Yamanaka; Guangchao Zhuang
How to cite: Morono, Y., Teske, A., Bojanova, D., Edgcomb, V., Meyer, N., Schubert, F., Toffin, L., and Galerne, C. and the IODP Expedition 385 Scientists: Microbial cell distribution in the Guaymas Basin subseafloor biosphere, a young marginal rift basin with rich organics and steep temperature gradient, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4098, https://doi.org/10.5194/egusphere-egu23-4098, 2023.
