(Table 3) Relative abundance of key diatom taxa in sediments from DSDP Hole 64-480 of the Guaymas Basin, Gulf of California

Counts were made at 500X, ignoring Chaetoceros spores and Thalassionema nitzschioides that dominate the sediment assemblages and mask subtle seasonal changes that occur in less common diatom taxa. In addition, small and delicate taxa (Fragilariopsis, Rhizosolenia, Thalassiosira) were not counted in order to reduce bias caused by differential dissolution and differential settling of pipetted samples