Possession Sound is located within Puget Sound of western Washington. Students at the Ocean Research College Academy (ORCA), a dual enrollment program in conjunction with Everett Community College, have collected environmental data in Possession Sound such as pH, and dissolved oxygen (DO) concentrations since 2004. Our group participated in this academic year, 2015-2016. Based on seasonal trends, it was hypothesized that pH of Possession Sound would be higher during summer, due to usage of CO₂ for photosynthesis, and lower during winter due to lack of photosynthesis. ORCA students collected water chemistry data at the sample site, Mount Baker Terminal, using a YSI 650, and analyzed the monthly mean value from 2010-2015. These monthly mean values showed that pH levels were highest in late spring and early summer months. These data of summer seasons’ correlation to higher pH levels supports our conclusion that less direct sunlight in winter season is linked with a higher acidity and lower pH while more direct sunlight provided in summer season is linked with lower acidity and higher pH levels. The pH levels were lowest during winter, January and February, at a pH of 6.81. The average rose in the spring months of March, April, and May to 7.72 while the average pH peaked during the summer months of June, July, and August was at a high of 7.97. However, it was shown that late spring had consistently higher pH levels. DO levels followed similar trends when investigating those levels. The average DO levels during summer months was 11.4, while the lowest was Fall at 9.88 instead of in expected winter. Although further evidence is needed to connect the fluctuations in DO and chlorophyll via biological processes to these observations of pH. Once this investigation is done, there will be a better understanding of the pH parameters marine organisms can withstand in the Possesion Sound.

Students from the Ocean Research College Academy (ORCA), a program through Everett Community College for high school students that focuses on marine science research, have collected monthly water quality data from the Possession Sound (PS) over the past twelve years. This longitudinal data set is combined with collections of current water quality by this research group. Nutrients play an important role in the health of the PS ecosystem. We evaluated the variations in the levels of phosphates and nitrates in relation to season in the north Whidbey Basin of Puget Sound from 2012-2015. Data were collected monthly from four locations in PS and we averaged these values to analyze the resulting trends in nutrient amounts. Surface water temperature was used as a proxy for the seasonal changes in direct sunlight. Nutrients and sunlight are required by phytoplankton for photosynthesis, so as phytoplankton populations increase nutrients become less abundant as they are utilized. Nitrates and phosphates were hypothesized to decrease in spring months because there was more photosynthesis taking place during the spring with increased sunlight, while the nutrients would peak in the winter. The resulting trends supported this hypothesis with the highest average levels of nitrates in October, at 15.54 μmol, and phosphates peaking in February at 2.15 μmol. The lowest average nitrate and phosphate levels occurred in June, at 3.08 μmol and 0.43 μmol, respectively. Our study gives insight into the health of the PS ecosystem by analyzing nutrients that limit the primary production of phytoplankton. Future parameters to be studied in correlation with this research include silicate and chlorophyll levels.
 

Students of Everett Community College’s Ocean College Research Academy (ORCA) analyzed pH trends in the Snohomish River estuary of Possession Sound using ten years of data. Influences on water chemistry include freshwater discharge from the Snohomish River and tidal currents in Possession Sound. In addition, high salinity, cold water from the Pacific Ocean may transport low pH water as a result of ocean acidification, when atmospheric carbon dioxide dissolves in seawater and decreases the pH. Students wanted to investigate whether average pH in Possession Sound had been decreasing over time. Data were analyzed during the winter months, November through March, from 2006 to 2016. We collected data from October 2015 through May 2016, with archived data collected by previous ORCA students. Water chemistry at three sample sites in the Possession Sound were compared. Recordings of pH from the surface to five meters were completed with a YSI 650 and averaged. The most significant decreases in pH occurred at locations in closer proximity to the shore, near south Whidbey Island and Mukilteo. Each had an overall decrease of 0.3, compared to only 0.1 in the middle of the sound near Hat Island. Decreased pH in an estuary system directly affects the development of many organisms, such as phytoplankton, which make up the primary levels of the trophic pyramid. Further investigation is ongoing about the effects of salinity and river discharge on these minimal decreases in pH, along with seasonal fluctuations in primary production by phytoplankton as well as the effects of decreased pH on phytoplankton.

Sources of heavy metals in the Snohomish River estuary system are influenced by both point and nonpoint sources; therefore, areas near the Snohomish River estuary are expected to have higher concentrations of heavy metals in the sediment during periods of high river discharge. At the Ocean Research College Academy, students develop research based studies through hands-on data collection in Possession Sound (P.S.). Our study focused on the effects of non-point sources on heavy metal deposits in P.S., both spatially and temporally. In consideration of the recent removal of the oil dock at Mukilteo, we hypothesized that higher levels of mercury and copper would be present at Mount Baker Terminal (MBT). Collection of arsenic and copper data involved in our group’s research were taken by previous cohorts at three sites in P.S.: Buoy, located closest to the mouth of the Snohomish River; Dolphin 1 (DOL), farther from shore near Hat Island and MBT, adjacent to Mukilteo. A Ponar type sediment grab was used to retrieve sediment from the various locations to be analyzed for heavy metal concentration at the Everett Environmental Laboratory. From 2012-2015, Buoy had higher heavy metal content than the other two stations; an average of 5.5 mg/L arsenic and 15.5 mg/L copper. Furthermore, Buoy showed the strongest seasonal correlations in 2014; DOL and MBT did not. The highest concentrations of heavy metals occurred during winter; an average of 6.5 mg/L arsenic and 16.1 mg/L copper. Buoy is nearest to the mouth of the Snohomish River; therefore, it is possible that river runoff heavily influenced arsenic and copper deposits at this station. Increased levels of heavy metals can be toxic for marine life and humans, which poses health concerns in environments with high concentrations. For future studies, the effects of heavy metal contamination on marine plants will be investigated.
 

Water chemistry and heavy metal data were collected from 2009 to summer 2015 by Ocean Research College Academy (ORCA) students and we continued sampling in Possession Sound in fall of 2015 to 2016. In June of 2015, the relocation of the Mukilteo Ferry Terminal began with the removal of the abandoned Tank Farm pier, at the Mukilteo location, eliminating creosote soaked pilings. It was hypothesized that the heavy metal concentrations in the sediments, as well as dissolved oxygen (DO) and pH levels, would differ both temporally, from before the removal of the pier in June of 2015 to January 2016, and spatially, between the Mukilteo site and Mount Baker Terminal (MBT) to the north. Benthic sediments were sampled offshore with a Ponar grab and analyzed by the Everett Environmental Laboratory for heavy metal concentration. DO and pH were sampled with a YSI-650. Copper, lead and zinc showed positive correlations, with an increase in the amount of heavy metals at Mukilteo from January 2009 to June 2015. Copper concentration increased by 503.31%, zinc concentration increased 573.33%, and lead concentration increased 437.20%. Additionally, amounts of heavy metals present in the sediment, regardless of temporal correlation, were consistently higher in samples from Mukilteo than samples from MBT, possibly due to proximity to the construction project. There was on average 154.27% more arsenic, 282.69% more mercury, 210.86% more cadmium, 157.95% more copper, 105.60% more lead, and 130.15% more zinc at Mukilteo. There appeared to be no changes to water chemistry in terms of DO and pH. Additionally, three other heavy metals, arsenic, mercury and cadmium, showed no temporal correlation. Further research on the bioaccumulation of heavy metals by marine organisms nearby would offer an intriguing look at the biological effects.