Sequoia’s Laser In Situ Scattering and Transmissometry (LISST) particle size analyzers have significantly advanced the understanding of flocculation in aquatic environments. Since the mid-1990s, LISSTs have often replaced or supplemented older technologies with in-situ and real-time measurements of floc size or primary particle size distribution and concentration. About 15% of published papers with LISST results focus on flocculation studies. LISSTs’ versatility allows their use in diverse environments, from lakes to oceans, studying floc dynamics from the surface to 6,000 m depth. If you study flocs or aggregates in-situ or in the lab, consider a LISST for your work. A comprehensive review is beyond this note, but LISSTs have been used to:

• Estimate flocculation time scales in situ and in the lab
• Investigate the influence of turbulence on flocculation
• Determine floc fractal dimensions and floc settling velocities
• Investigate how bed shear stress affects floc sizes and volumes
• Study flocs in the lab, and in-situ in fresh, brackish and marine environments
• Develop models for sediment transport purposes in rivers, estuaries and the ocean
• Study oil-mineral aggregates in connection with oil spill research
• Elucidate the aggregation and settling of dying algae
• Measure the primary particle size distribution of flocs in situ
• Investigate organic content impact on flocculation and sediment transport
• Study aggregation processes in (harmful) algae blooms, and dredging and deep-sea mining plumes

Ackleson et al. (2020) used a LISST-100X to show how flocculated primary particles (red lines) break up into smaller flocs at progressively higher shear (dotted lines). Figure used under CC by 4.0 license ( https://doi.org/10.1002/lom3.10391 ).

The instrument design developed by Ackleson et al. (2020) to collect the data shown above. Figure used under CC by 4.0 license ( https://doi.org/10.1002/lom3.10391 ).

Flocculation references available in Sequoia’s technical library.