Understanding The Fluid Mechanics of Algal Bloom Across Scales

Introduction

One of the most life-threatening consequences of global warming is the perturbation of natural ecosystems. Among the detrimental impacts, the increased frequency and intensity of Cyanobacterial blooms (overgrowth of microscopic bacteria in aquatic systems) seriously threaten drinking water and devastate ecosystems and the economy.

Challenge

The challenge now is to accurately predict the formation of Cyanobacterial blooms and find feasible mitigation strategies. This poses a new paradigm in complex fluids and flows where rheology, fluid mechanics, and biophysics are intertwined across scales:

1. Rheological properties on the microorganism level (few microns)
2. Mesoscopic phenomena of formation and fragmentation of Cyanobacterial colonies (hundreds of microns)
3. Macroscopic dispersion of colonies under laminar and turbulent flows in the aquatic system (meters)

Hence, fundamental knowledge of rheology and fluid mechanics of Cyanobacterial bloom formation is urgently needed.

Methodology

I will tackle this multiscale problem with a set of highly controlled laboratory experiments and numerical simulations. The novel experimental setups combine:

• Rheological methods
• Advanced mechanical manipulation of cells
• Tomography
• Particle tracking
• Flow visualization
• Microscopy

The combination of experiments, statistical modeling, and simulations will result in many first-ever measurements and analyses, unraveling the rheological and mechanical properties of the cells/colonies, and revealing details of aggregation and fragmentation of Cyanobacterial colonies under various hydrodynamic and environmental conditions.

Objectives

This project lays out an ambitious effort to overcome current limitations and uncover the complex multiscale interactions between rheology, fluid mechanics, cell biophysics, and colony formation and fragmentation. My findings will open new avenues in creating prediction tools and effective solutions to combat Cyanobacterial blooms.