EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Microbial cell distribution in the Guaymas Basin subseafloor biosphere, a young marginal rift basin with rich organics and steep temperature gradient

Yuki Morono1, Andreas Teske2, Christophe Galerne3, Diana Bojanova4, Virginia Edgcomb5, Nicolette Meyer6, Florian Schubert7, Laurent Toffin8, and the IODP Expedition 385 Scientists*
Yuki Morono et al.
  • 1JAMSTEC, Kochi, Japan (
  • 2Department of Marine Sciences, University of North Carolina at Chapel Hill, USA
  • 3GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
  • 4Department of Earth Sciences, University of Southern California, USA
  • 5Department of Geology and Geophysics, Woods Hole Oceanographic Institution, USA
  • 6Department of Earth System Science, Stanford University, USA
  • 7Section Geomicrobiology, German Research Centre for Geosciences (GFZ Helmholtz Centre Potsdam), Germany
  • 8IFREMER, Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, France
  • *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. This continuum of interrelating processes from magma to microbe motivated International Ocean Discovery Program Expedition 385 and is reflected in its title, “Guaymas Basin Tectonics and Biosphere.”

During IODP Expedition 385, organic-rich sediments with sill intrusions on the flanking regions and in the northern axial graben of Guaymas Basin (in eight sites) were drilled and core samples were recovered. 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.

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.

IODP Expedition 385 Scientists:

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., Galerne, C., Bojanova, D., Edgcomb, V., Meyer, N., Schubert, F., and Toffin, L. 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 2022, Vienna, Austria, 23–27 May 2022, EGU22-3312,, 2022.