Autonomous gliders traversing across shore sections of the California Current are powerful tools for continously measuring hydrographic properties, chlorophyll a fluorescence and acoustic backscatter (at 750kHz) in the CCE study area. Sharp fronts in hydrographic properties seem to co-occur with biological fronts assoctiated with chl a fluorescence and acoustic backscatter (which is a rough proxy for zoolankton biomass). This poster examines criteria for defining both physical and biological fronts as well as the strength of interaction between the fronts.