ABSTRACT
The arthropod Megabalanus coccopoma is indigenous to coastal Baja California, but migrated up to San Diego due to an El Nino event in the early 80s (Newman and McConnaughey 1987). Megabalanus dates back to the Miocene (Doyle et al. 2007) is a useful local indicator of exposure and submergence intervals due to their feeding habits which correlates to propagation of growth patterns in the calcium carbonate produced shell. This barnacle was used as a dataset for tidal analysis of its exposure history in the eulittoral zone off the coast of San Diego. After four spring tide events, outplant samples were collected from the number 17 piling of the Scripps Institute pier, along with a data logger, and thin sectioned using an Isomat Micromill. A microscope using transmitted light through the anterior dorsal shell section gives spatial markings associated with exposure/submergence events. A calcein dye was incorporated to bond with the calcium before outplant to mark the initial growth of the experiment. A fluorescence scope showed multiple fluorescence lines (excitation/emission configuration of 495/515nm), not a singular line for the start of the outplant, indicating discrepancies in the dye bonding, or shell flourescence. Ocular observation and point count of individual growth lines in the shell with matching tidal data from the logger shows similar spatial data. This growth model seems sufficient for marking paleoclimatic tidal data, although further investigation into marking the outplant date growth line is needed.