SPATIAL PERSISTENCE AND SEDIMENT DISTURBANCE OF AN ARENICOLID POLYCHAETE

Field evidence suggests that biogenic sediment movement influences the distribution of infauna but also that biogenic processes account for only a small proportion of total sediment movement. This difference ma y be due to biogenic additions to the sediment or the mode of biogenic vs. physical deposition or to calculation of the biogenic effect as i nappropriately scaled temporal and spatial averages. Spatial persisten ce of biogenic effects over time would bias such averages. Individuals of the arenicolid polychaete Abarenicola pacifica can be sized and ma pped by the diameter and position respectively of their fecal coils. T heir spatial distributions show significant clumping. Both individuals of A. pacifica and their biogenically disturbed patches have consider able spatial persistence over time. Individuals remained in the same s patial location for up to 12 d. Over 50% of all patches of biogenic se diment disturbance persisted for at least the 16-d observation period, and the patches were highly localized. Thus spatial and temporal aver ages may be inappropriate for determining the importance of biogenic e ffects, due to nonuniform distribution of individuals and their spatia l and temporal persistence.