title: A study of fecal coliform sources at a coastal site using colored dissolved organic matter (CDOM) as a water source tracer.
abstract: Optical properties of colored dissolved organic matter (CDOM) were measured as a tracer of polluted waters in a Southern California surf-zone with consistently high levels of fecal indicator bacteria. Salinity, temperature, fecal coliform, absorbance (200-700nm) and fluorescence (lambda(excitation)=350nm; lambda(emission)=360-650nm) were measured in the creek and surf-zone during a dry and rain event. Fluorescence to absorption ratios for CDOM were used to distinguish water masses, with two distinct CDOM end-members identified as creek (flu/abs=8.7+/-0.8x10(4)) and coastal (flu/abs=2.2+/-0.3x10(4)). Waters containing the same CDOM end-member had highly variable bacterial levels during the dry event, suggesting intermittent sources of bacteria added to a uniform water source, consistent with marine birds. During the rain event, increased levels of the creek end-member and bacteria indicated a second bacteria source from runoff.
authors.affiliation: Department of Chemistry, Chapman University, One University Drive, Orange, CA 92866, USA. cclark@chapman.edu
authors.forename: Catherine D
authors.initials: CD
authors.lastname: Clark
authors.forename: Adam P
authors.initials: AP
authors.lastname: O'Connor
authors.forename: Denise M
authors.initials: DM
authors.lastname: Foley
authors.forename: Warren J
authors.initials: WJ
authors.lastname: de Bruyn
mesh_terms: D002140:California; D015169:Colony Count, Microbial; D003116:Color; D004755:Enterobacteriaceae / Q000302:isolation & purification*; D004784:Environmental Monitoring / Q000379:methods*; D005243:Feces / Q000382:microbiology; D014871:Water Microbiology; D014873:Water Pollutants / Q000302:isolation & purification*
chemical_list: D014873:Water Pollutants