EXAMINING MORPHOLOGICAL CHARACTERISTICS OF FORAMINIFERA IN DIVERSE OXYGEN ENVIRONMENTS: A CASE STUDY IN THE SOUTHERN CALIFORNIA BIGHT

Paleoceanographic studies often use foraminifera because of their rapid adaptation to environmental changes and ease of preservation. Changes in oxygen conditions affect foraminiferal morphology. To investigate foraminiferal ecology, abundance, and morphology, an oxygen transect will be used off the coast of San Diego. This region's foraminiferal assemblages are believed to be more affected by sediment grain size than oxygen availability demonstrated by Cibicidoides wuellerstorfi being found in greater abundance despite the low oxygen availability. A correlation has been found between I/Ca, test porosity, and oxygen availability in bottom waters during test formation. Although smaller surfaces are commonly thought to be an adaptation to low oxygen, this has not been explicitly demonstrated in foraminifera. It has been found that proloculus diameter is related to oxygen suggesting oxygen influences overall proloculus diameter. As individuals develop, pore conduits are likely to remain crucial if they facilitate oxygen respiration. This study examines relationships between total test volume, pore conduits, and available oxygen. MicroCT scanning will facilitate the measurement of proloculus volume and pore conduits which will be compared along the oxygen transect. As a result of our observations, we will establish another mechanism (along with surface pore variations) for examining oxygen's influence on benthic foraminiferal development. To mitigate and manage OMZ expansions, simple techniques to detect and assess deoxygenation will be needed under future climate change scenarios. Using the volume and chamber development of benthic foraminiferal tests may be a simple tool to assess modern expansion and extrapolate information from OMZs of the past.