Aggregation of Biogenic Particles with Clay

Jessie Owens, Dr. James Bonner*, Michael Sterling, Dr. Cheryl Page, and Temitope Ojo

Throughout the water column there are many particles both biogenic and lithogenic.  These particles either remain in suspension or make their way through the water column to become bottom sediments.  Aggregation in the water column causes many of the particles to increase in density and size causing settling.  Many studies have been conducted identifying clay aggregation processes and pure phytoplankton aggregates, but not much has been done with coaggregation of phytoplankton with clay, which is a familiar phenomenon in aquatic systems. 

To examine the interactions of phytoplankton with clay particles, the algae Chlorella kessleri was grown from cultures received from the UTEX culture collection of algae.  Once these cultures were grown, experiments were conducted on mixtures of clay and algae.  A known dose of Fe (III) was added to the mixtures, and the effects on flocculation were observed.   Analyses were performed using the Coulter Counter Multisizer, which measures size distributions of particles.  The data from the Coulter Multisizer was used to create size distribution graphs and to run a flocculation model.

A field component of the research included a two-day survey expedition on Corpus Christi Bay.  Instruments deployed included a LISST 100 particle analyzer, a FastCat CTD sensor (salinity, temperature, depth), an ADCP (acoustic Doppler current profiler), and ECO-FL3 (fluorometer).  In addition, I attended various sessions of a graduate civil engineering course being taught by Dr. Jim Bonner.  We were exposed to many different types of sea equipment currently being used or in development, and there were field opportunities for instrument deployment during the course.

 Power Point Presentation: 

*Conrad Blucher Institute, Texas A&M-Corpus Christi