Possession Sound as a part of the larger Puget Sound is located between the Whidbey and Snohomish county shoreline. This location has significant influence from both freshwater and nutrient inflow from the Snohomish River as well as saline water resulting from tidal exchange. Students at the Ocean Research College Academy (ORCA), an early college program at Everett Community College, have been conducting baseline estuarine monitoring since 2007. The Washington State Department of Ecology has been aerially monitoring phytoplankton blooms and maintains a long-term collection of nutrient data throughout Puget Sound. According to this data set there has been a nutrient shift that is hypothesized to impact diatom abundance. This project combines the ORCA data set of plankton levels and nutrient concentrations to see if a similar shift is occurring in Possession Sound. Additionally, temperature variation is analyzed. Two hypotheses combine to identify special and temporal distribution of nutrients and plankton abundance. First, when silicate levels decline, diatomaceous phytoplankton are limited by this reduction. Second, the deep water location further from the river will have less variation in temperature, less nutrient availability and subsequently less phytoplankton abundance and diversity. The location nearest to the mouth of the Snohomish Riveris predicted to experience dramatic temperature variation and higher seasonal nutrient levels. The conclusions from this work will influence future plankton enumeration protocols at ORCA.

Puget Sound consists of many smaller bodies of water including Possession Sound, located between the cities of Everett and Mukilteo, Washington. The Asarco Smelter, located in North Everett was active around 100 years ago, resulting in heavy pollutants such as lead into the Snohomish River leading to Possession Sound. The Ocean Research College Academy (ORCA) students sample Possession Sound for sediments monthly. It can be hypothesized that the lead concentration will be higher at the location Buoy, because it is closer to the fresh water outputs such as the Snohomish River. Consequently, the location Mukilteo/Mount Baker Terminal (MUK/MBT), that is further south in Possession Sound, will have a lower lead concentration since it is further away from the Snohomish River in comparison to Buoy. According to the data collected, from 2009 to 2013, Buoy had a higher amount of lead concentration in comparison to MBT/MUK. However, factors to be considered are other anthropogenic influences, river discharge, tidal stages, time such as time of day, what season and the time of year the data was collected, as well as water currents that could impact the lead concentration in Possession Sound. Future studies will consist of scrutinizing organic matter in sediments in correlation with lead concentration to analyze if biological organisms are impacted by the amount of lead present in sediment.