THE PALEOECOLOGY OF PLEISTOCENE OYSTER BEDS, SAN PEDRO, CALIFORNIA

Oysters decline dramatically within southern California coastal waters throughout the Quaternary, yet the active tectonic boundary remains constant and its geographic location only differs by a few degrees. Oyster diversity steadily declined from four species in the early Cenozoic to two oyster species in the Pleistocene, to finally, only one native species presently remaining: Ostrea lurida. Biologists attribute the decline of oyster beds to industrialization and urbanization of southern California. Restoration efforts continue within southern California but researchers lack the deep-time historical perspective of oyster beds. Here, we examine Pleistocene oyster populations and ecology to better understand pre-human oyster habitats. Three undergraduate students will each examine a five gallon bucket of sediments and document the fossil content. Samples were extracted from Knoll Hill, San Pedro, California. The specimens were preserved in the Late Pleistocene Palos Verdes Sands. The samples will be cleaned, sorted and all fossils will be identified to the species level and counted. Length and width measurements of all oyster fossils will be recorded and growth lines along the oysters shell will be counted to determine the oysters age. The data collected will provide an image of species abundance and diversity in the region prior to urbanization. This data has the potential to help guide current restoration efforts. Restoring southern California oyster beds will improve the local shallow marine ecosystems in several ways. A flourishing oyster population provides filtration of the local waters, reduces the abundance of carbon, provides fishery resources, establishes a marine habitat for other organisms, produces more oysters, increases landscape diversity, and stabilizes intertidal and benthic habitats.