Local high school students model watershed bacterial dynamics

"Is the water safe to swim in ?" That's the question that crossed the minds of Annie Chang and Daisy Chen, two 9th graders from Woodbridge High School, Irvine, and brother-sister team Hari and Anita Garg from University High School, Irvine after observing the confluence of pets, toddlers and river effluent at one of our local beaches last summer. They wondered whether certain sites in our local watershed harbor high concentrations of coliform bacteria that might elevate risks to human health. So they set out to find some answers. But what initially had seemed like a straight forward question, they quickly came to realize was a complex problem with no easy answers and no simple single methodology.

Under mentorship from Dr. Felix Grün (CCBS) and Dr. Michelle Digman (BME) they spent last summer collecting water samples along the ocean coastline, at river outlets and throughout Newport Bay, and analysing them for bacterial contaminants using a variety of quantitative laboratory techniques including bacterial colony forming plate and growth assays, species-specific qPCR, and applying a novel sensitive fluorescence particle counting instrument developed at UCI's Laboratory of Fluorescence Dynamics. Quantitative data on bacterial levels - along with real time weather, tidal and water flow data - were then used as input parameters for a research grade hydrodynamic and biogeochemical computational simulator (ELCOM-CAEDYM, Centre for Water Research, UWA) able to model the three-dimensional temporal and spatial dynamics of complex water transport processes and their ecological responses.

Annie and Daisy's modeling results, together with Hari and Anita's surveys, highlighted the highly dynamic (and sometimes surprising) interactions throughout our watershed. Notable was the distribution of high coliform counts in the Upper Bay around areas of freshwater input sources, e.g. runoff from marshes and golf courses, that were also subject to inefficient tidal flushing, and the rapid decline in viable bacterial counts at most ocean locations due to dilution effects and inhospitable growth conditions. So appearances aren't everything: the Upper Newport Bay ecological preserve might look tempting but is not a good place for a swim; swimming close to the Santa Ana river outlet ... well that depends on the time, tide and weather events.

2015IRWD winnersAnnie and Daisy won 1st Prize in Environmental Science for their project entitled "Multimethod Analysis and Spatial Modeling of Bacterial Dynamics in the Newport Bay Watershed" at the Orange County Science & Engineering Fair in April and took 4th place at the California statewide competition held at the Staples Center, Los Angeles in May. Their work also received recognition with additional awards from the Irvine Ranch Water District, Orange County Sea and Sage Audobon Society and the California Shore and Beach Preseveration Association. Hari and Anita Garg also excelled with their project entilted "Pathogen Detection in Southern California Water Using a Particle Counter" being recognized by a special IRWD award, a 3rd Place in the Biological Products section of the OCSEF and also going on to compete at the California statewide competition. Congratulations to all !


2011 Local high school students model watershed bacterial dynamics. Copyright © 2013. The Center for Complex Biological Systems, UC Irvine
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