Practicum Project | 2011

Southern California surf zone water quality: Fecal indicator bacteria and harmful algal bloom cells at the Santa Monica Pier and Malibu Surfrider Beach

Students: Tristan J. Acob, Taylor Cochran, Soo Yeun Park, Samuele L. Schoenberg, Samantha Tang, and Shannon Walker

Client: Heal The Bay

Advisor: Dr. Rebecca Shipe

Final Report

Surf zone water quality is directly related to human health and that of the coastal ecosystem. Fecal indicator bacteria (FIB) and harmful algal bloom (HAB) cells are microbiological indicators of water quality that periodically occur in the surf zone of southern California waters. Negative impacts of high FIB and HAB concentrations include contaminated waters and marine life, ecosystem disruptions, beach closures, and human illnesses. Previous research has addressed parameters that increase FIB and HAB concentrations independently, yet none have examined if FIB and HAB are directly related. Our main study objective asks if a correlation exists between FIB and HAB, and how ecological/environmental conditions (onshore vs. offshore, salinity, total suspended solids, temperature, and precipitation) may affect their growth. We collected water Monday through Thursday from Santa Monica Pier (SM) and Tuesday and Thursday at Malibu Surfrider Beach (MS) onshore and 100m offshore for 7 weeks. FIB concentrations were higher at MS onshore, whereas there was no onshore vs. offshore difference at SM. HAB abundances were higher offshore than onshore at both MS and SM. Onshore salinity and total suspended solids concentrations were lower at MS than at SM. Moreover, there was no significant relationship between FIB and HAB concentrations. Variability in FIB and HAB concentrations may best be explained by site differences and precipitous weather events