Environmental Monitoring Using Foraminiferal Assemblages in the Great Bend Region of Hood Canal, WA

This study utilizes benthic foraminiferal assemblages to explore the role of anthropogenic pollution in ecological changes to the Great Bend region of Hood Canal in Puget Sound. Hood Canal is a restricted waterway which is home to economically important fisheries and a military base. Within the waters of Hood Canal, seasonal hypoxia and eutrophication cycles have been attributed to natural causes and non-point source pollutants. Eleven grab samples from locations in the Great Bend area of Hood Canal were analyzed to explore the relationship between benthic foraminiferal assemblage sand anthropogenic pollution in this basin. Samples were collected in 1992 by Shoreline Community College and in 2013 by the Department of Ecology and the United States Geological Survey. Both years the foraminiferal assemblages are dominated by calcareous species, but with substantial components of agglutinate taxa. In 1992 the most prominent species were Buccella frigida, Buliminella elegantissima, and Eggerella advena. The 2013 dominant assemblage was B. elegantissima, Elphidium excavatum, Nonionella stella and Ammobaculites sp.. The presence of E. advena (an opportunistic species) may indicate stressed environments, such as sewage outfall and industrial pollution, while the B. elegantissima and N. stella are often found in dysoxic environments. Ammobaculites is often found in environments with an abundance of nutrients. Species richness in Hood Canal is higher than many other locations in the Puget Sound, with 23 species in 1992 and 26 in 2013. Diversity indices, however, show a small decrease between sample years; higher diversity indices often suggest a healthier habitat. The increase in assemblage dominance of dysoxic and high nutrient indicator species in 2013 suggests an increase in eutrophication in this portion of Hood Canal. The decrease in E. advena in 2013 may signal less anthropogenic stress, however with diversity indices also showing a decrease, the picture is unclear