ABUNDANCE AND DISTRIBUTION OF MODERN FORAMINIFERA SPECIES IN THE SOUTHERN PUGET SOUND, WASHINGTON STATE

The Puget Sound is the southern portion of the Salish Sea, a complex fjord system located in Washington State, USA, and British Columbia, Canada. Over the last 150 years the entire Puget Sound system has been subjected to significant anthropogenic impacts and continues to have rapid population growth. The combination of rapid growth and a history of anthropogenic impacts highlight the need for the development of biologic models to track the health of the Sound. Foraminifera have shown promise as indicators of environmental status of estuarine waters.

Between 1982 and 1991 a large number of grab samples were collected in the Southern Puget Sound by Robert Harman (Shoreline Community College). Puget Sound is regularly flushed with normal marine waters because of a significant tidal flux through the Juan de Fuca Strait that extends over 100 km south to the distal embayments. Oceanographic setting range from tidal channels within the Nisqually River delta to open inlets. Depths range from 1 to >100 meters. Sediment composition is dominated by fine sand and mud, with coarser clastics in shallow nearshore water. Some samples contain significant amounts of plant material other samples have indications of low O2 concentrations based on sediment color. Within the data set 111 samples with recoverable locality data were examined for Foraminifera. Of these 99 of 111 samples contain at least a limited Foraminiferal fauna and 10 samples produced <100 specimens. The remaining samples contained sufficient foraminifera to conduct 300+/- counts. The most common species are Elphidium excavatum, Buccella frigida, Eggerella advena, Buliminella elegantissima, Elphidiella hannai, Deuterammina rotaliformis, Lagenammina arenulata, and Trochammina pacifica. Together these 8 species comprise more that 90% of the total fauna. The Foraminifera distribution in these samples provides a baseline for mapping faunal changes in future sampling in this area of the Puget Sound.