Can we distinguish tsunami and storm deposits based on their microbial composition?

 

Can we distinguish tsunami and storm deposits based on their microbial composition?

 

Wenshu Yap^1,2,3, Adam D. Switzer ^1,2, Chris Gouramanis⁴, Dale Dominey-Howes⁵, Maurizio Labbate⁶, Federico M. Lauro^1,3

 

¹ Asian School of the Environment, Nanyang Technological University, 50 Nanyang Drive, Singapore 639798

² Earth Observatory of Singapore, Nanyang Technological University, 50 Nanyang Drive, Singapore 639798

³ Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798

⁴ Department of Geography, National University of Singapore, Kent Ridge, Singapore 117570

⁵ Asia-Pacific Natural Hazards and Disaster Risk Research Group, School of Geosciences, University of Sydney, NSW 2006, Australia

⁶ School of Life Sciences, University of Technology Sydney, NSW 2007, Australia

 

One of the challenges in the study of coastal hazard is to reliably distinguish between storm and tsunami deposited sediments. This limitation compromises the quality and accuracy of reconstructing historical coastal flooding records, and is thus an issue to a variety of policy makers and stakeholders interested in assessing the risk and vulnerability of coastal communities. Here we describe a microbial community signature based on amplicon sequencing of DNA extracted from environmental samples collected from two different locations i.e. Cuddalore, India and Phra Thong Island, Thailand. Both locations were impacted by the 2004 Indian Ocean Tsunami and a subsequent storm event. Our results show that the microbial community in the tsunami deposits are significantly different from that found in the storm deposits as well as soil and terrestrial sediments (PERMANOVA, p-value <0.01) in both locations. The microbial community differences between the tsunami deposits and storm deposits are not statistically correlated with chemical data such as total Nitrogen, total Carbon and total Sulfur, implying that our microbial signature is insensitive to environmental and geochemical variability. Integrating molecular techniques to investigate geological records is powerful and statistically robust in discriminating between modern tsunami and storm deposits.