Poster R16 - Impact of Shear Flow on Marine Biofilms Using Hyperspectral Imaging

Introduction: Marine biofilms, dense and highly heterogeneous microbial communities, adhere to submerged surfaces and play critical roles in marine ecosystems. These biofilms vary in thickness, roughness, and composition based on environmental conditions, necessitating the tracking of different bacterial strains. The significant impact of shear stress, induced by water flow, on the formation and characteristics of biofilms is a key area of study. Our research aims to explore how prolonged exposure to shear flow in an environment that replicates natural conditions affects the composition, behavior, and detachment of marine biofilms. We utilize a hyperspectral imaging setup that provides high spatial and spectral resolution data to identify the characteristics of marine biofilm samples.

Materials and

Methods: We employed a supercontinuum light source that emits a broad spectrum of wavelengths to image various strains of bacterial biofilms and gather their individual spectral information. The biofilms were analyzed on a glass substrate within a flow chamber filled with low-nutrient media. Combining spectral data allowed for the identification of the composition of different strains within the flow chamber samples. Hyperspectral data ranging from 550 nm to 850 nm was acquired under flow rates varying from 1 milliliter per second to 26 milliliters per second. An algorithm was developed to process this data, enabling the identification of different bacterial strains over time and under varying flow conditions.

Results, Conclusions, and Discussions: Initial hyperspectral data captured under normal environmental conditions provided baseline information on the composition and distribution of bacterial strains in the biofilm. Under high-shear flow, biofilms formed filamentous streamers, whereas low-shear conditions favored the development of isotropic, mound-shaped micro-colonies. The influence of shear stress was pronounced during biofilm maturation, significantly altering morphology and composition. Hyperspectral imaging detected these architectural changes, revealing how biofilms adapt to increased shear forces by enhancing mass transfer, increasing density, and elevating viscosity. This study enriches our understanding of biofilm responses to mechanical forces and provides insights into the interplay between shear stress and biofilm architecture.

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