12:00 PM - 12:15 PM
[ACC33-12] Development of a simple and rapid automated method for analyzing microbial cells in ice cores
Keywords:Microbial classification, Automated cell counting, Ancient microorganisms, Cloud physical properties, Bioaerosols, Ice nucleating particles
Ice cores preserve aerosols deposited along with snowfall, including microbial cells, which are a type of bioaerosol. Recent observations over polar oceans have revealed the importance of marine-origin bioaerosols functioning as ice nuclei (Sato and Inoue, 2023). Changes in aerosol sources associated with global warming may influence the phase state of clouds (liquid or ice clouds), and thus their physical properties. Since this is closely related to the Earth's radiation balance and water cycle, there is growing interest in its contribution to the mass changes of the Antarctic and Greenland ice sheets. We are attempting to develop methods to analyze microbial cells in ice cores to clarify the past dynamics of bioaerosols in both polar regions and their relationship to climate change.
In previous studies, microbial cell counts in ice cores were conducted using direct observation with fluorescence microscopy or flow cytometry (Uetake et al., 2012; Santibáñez et al., 2016, 2018). However, these methods involve complex sample staining procedures and are time-consuming, which are major issues in ice core studies requiring the analysis of many samples. This research attempts to automate microbial cell concentration measurements using a device that does not require sample pretreatment and enables analysis within approximately 10 minutes per sample. In addition to measuring cell concentration, this device has the potential to classify fungi as well as Gram-positive and Gram-negative bacteria. This presentation introduces the results of preliminary experiments conducted to establish this new method.
References
Uetake J., Goto-Azuma, K., Motoyama, H. (2012). Improved direct-count method by fluorescence microscope for low-biomass ice core. Nankyoku Shiryô (Antarctic Record), 56(1), 57-67 (in Japanese with English abstract).
Sato, K., Inoue, J. (2023). Ice cloud formation related to oceanic supply of ice-nucleating particles: A case study in the Southern Ocean near an atmospheric river in late summer. Geophysical Research Letters, 50, e2023GL106036. https://doi.org/10.1029/2023GL106036
Santibáñez P. A., Maselli O. J., Greenwood M. C., et al. (2018). Prokaryotes in the WAIS Divide ice core reflect source and transport changes between Last Glacial Maximum and the early Holocene. Glob Change Biol., 24, 2182–2197. https://doi.org/10.1111/gcb.14042
Santibáñez, P., McConnell, J. R., Priscu, J. C. (2016). A flow cytometric method to measure prokaryotic records in ice cores: An example from the West Antarctic Ice Sheet Divide drilling site. Journal of Glaciology, 62, 655–673. https://doi.org/10.1017/jog.2016.50
In previous studies, microbial cell counts in ice cores were conducted using direct observation with fluorescence microscopy or flow cytometry (Uetake et al., 2012; Santibáñez et al., 2016, 2018). However, these methods involve complex sample staining procedures and are time-consuming, which are major issues in ice core studies requiring the analysis of many samples. This research attempts to automate microbial cell concentration measurements using a device that does not require sample pretreatment and enables analysis within approximately 10 minutes per sample. In addition to measuring cell concentration, this device has the potential to classify fungi as well as Gram-positive and Gram-negative bacteria. This presentation introduces the results of preliminary experiments conducted to establish this new method.
References
Uetake J., Goto-Azuma, K., Motoyama, H. (2012). Improved direct-count method by fluorescence microscope for low-biomass ice core. Nankyoku Shiryô (Antarctic Record), 56(1), 57-67 (in Japanese with English abstract).
Sato, K., Inoue, J. (2023). Ice cloud formation related to oceanic supply of ice-nucleating particles: A case study in the Southern Ocean near an atmospheric river in late summer. Geophysical Research Letters, 50, e2023GL106036. https://doi.org/10.1029/2023GL106036
Santibáñez P. A., Maselli O. J., Greenwood M. C., et al. (2018). Prokaryotes in the WAIS Divide ice core reflect source and transport changes between Last Glacial Maximum and the early Holocene. Glob Change Biol., 24, 2182–2197. https://doi.org/10.1111/gcb.14042
Santibáñez, P., McConnell, J. R., Priscu, J. C. (2016). A flow cytometric method to measure prokaryotic records in ice cores: An example from the West Antarctic Ice Sheet Divide drilling site. Journal of Glaciology, 62, 655–673. https://doi.org/10.1017/jog.2016.50