The introduction of harmful strains of Escherichia coli (E. coli) in the marine environment negatively impacts ecosystem health. When unnatural strains of E. coli are introduced through pollution events, spikes in animal sickness and death occur, and harm to human health is more likely. Understanding relationships among parameters known for contributing harmful strains of E.coli and parameters more likely to contribute non-harmful strains is important to identify the most impactful parameters leading to harmful E. coli events. Possession Sound, WA is an ideal study site for monitoring multiple parameters associated with the introduction of E. coli to a saltwater environment. The study site includes the second largest freshwater input in Puget Sound, the Snohomish River, which passes many farms on its way to the Sound. The study site is also surrounded by a heavily industrialized port, and a large-density population center. I collected water samples at various depths and recorded animal presence from 2023-2025 at ten separate sites. Using a sterile procedure, I plated water samples onto bacterial plates using Easygel® agar. Overflow and river discharge data were provided by the city of Everett and USGS respectively. Historical data were collected following similar protocols by the Ocean Research College Academy. I hypothesized that increased presence of E. coli would strongly correlate with high river discharge events and combined sewer overflow events more than other inputs, but early analysis does not support this correlation. Further research must consider parameters such as residence time of E. coli, lag time after discharge events, and water chemistry characteristics. 

Sewage system design and heavy seasonal rainfall throughout Washington State pose risks to many marine ecosystems, as stormwater overflow can flush untreated waste into local bodies of water. The estuarine system and status of the Snohomish River as the second-largest freshwater input into Puget Sound make this area especially interesting and relevant to a larger environment. While sewer overflow events pose risks, the extent of their impact on our local water chemistry remains fairly unexplored. Studies conducted across the US suggest that this mix of human waste, debris, and potentially harmful microorganisms and chemicals in hundreds of thousands of gallons at a time can cause significant negative effects on many aspects of marine life, notably dissolved oxygen (DO), to the point of hypoxia. This study seeks to quantify the impact of combined sewage overflows (CSOs) in the Snohomish River and Possession Sound by analyzing trends seen between DO and chlorophyll levels at the mouth of the Snohomish River during low tides occurring before and after major CSO events. CSO outflow data were provided by the City of Everett’s Utilities department and DO and chlorophyll data were collected by a long-term deployed EXO 2 in the Everett marina. I hypothesized that there would be a significant negative correlation between CSO volume and DO levels and a positive correlation between CSO volume and chlorophyll. This research will help assess the risk of hypoxia, an important measurement as many marine species cannot survive in low oxygen conditions, and it will add to an important discussion about how our human systems impact marine life.

Eelgrass meadows (Zostera spp.) and Kelp forests (Nereocystis spp.) are both essential habitats in Possession Sound, a saltwater estuary formed where the Snohomish River meets the Salish Sea. Home to many marine species, the Possession Sound has unique salinity levels that provide a rich environment to support marine life. These ecosystems provide vital services such as helping clean the water, sheltering fish, absorbing or filtering carbon, producing oxygen, and protecting coastlines. Given the rich marine habitat that develops in eelgrass meadows and kelp forests, conducting a study of the organisms that reside in the habitat would be beneficial to learn about their condition and influence on life within Possession Sound. To conduct the study, I used eDNA sampling for data collection. eDNA sampling analyzes genetic material from organisms and identifies what species are present in a given environment. I collected samples from two ecosystems at the stations closest to each habitat. MBT (eelgrass) and Kelp Sanctuary (kelp forest). The data I collected from the two sites were sent to the molecular genetics laboratory at WDFW for metabarcoding analysis to identify species using a passive filtration protocol. The data were then combined with historic data to determine the species present in both habitats, specifically focusing on fish and crustacean species. Preliminary analysis suggests that these habitats have similar organisms that frequent each habitat. I expect to see this trend reflected in additional eDNA data, meaning the eelgrass meadows and kelp forests will have similar representative species.

Gray whales in the North Pacific annually migrate north to the Gulf of Alaska and the Bering Sea, and their migration route bypasses the Salish Sea. Roughly a dozen of these whales, commonly called “the Sounders,” have detoured their migration into North Puget Sound since the 1990s. These whales have been observed feeding on ghost shrimp in the intertidal area of sediment beaches in North Puget Sound, using a high risk strategy of feeding on shrimp at high tides. This feeding strategy leaves large indents, or “feeding pits”, in the sediment that are revealed at low tide and can provide insight into the Sounders’ feeding habits and contribute to a deeper understanding of the North Pacific gray whale population. My research focused on locational trends of gray whale feeding pits on Jetty Island West beach, and I observed longitudinal locations of specific pits in the intertidal zone to investigate feeding patterns. I observed feeding pits with drone imagery collected at low tide and compiled into aerial maps, or “orthomosaics,” and I compared feeding pits in different longitudes to observe where on the beach whales are feeding. Two seasons of feeding pit imagery were collected from late winter and spring of 2024 and 2025, and I have analyzed the imagery using ArcGIS pro. Survey site area ranged from approximately 0.09km² to 0.4 km² for different maps. The non-invasive nature of drone photogrammetry has recently increased its use in marine and biological research, and this method of data collection is ideal for surveying gray whale pits on Jetty Island. Because of the increased risk of feeding in higher tidal zones, I expect to find higher concentrations of feeding pits at lower tidal zones.

Noise pollution from 10 Hz to 200 kHz disrupts marine life and importantly damages cetaceans’ ability to navigate surroundings, communicate, and hunt. Possession Sound supports gray, humpback, and orca whales who all pass through its congested waterways and underwater soundscape. During 2023-2024 a voluntary slow down of commercial vessels occurred in Puget Sound. The results from Quiet Sound showed that 71% of 795 commercial vessels slowed down through the marked zones. There was a 50% 3 dB decrease in sound created and resulted in 72 additional minutes when underwater noise did not reach over 110 dB. One location where noise pollution is prominent is between the city of Mukilteo and the town of Clinton on Whidbey Island. The Mukilteo-Clinton ferries run 21 and a half hours a day, leading them to be a regular contributor to the underwater soundscape and an important factor to assess our environment's health. This study was conducted using data from a SoundTrap 400 hydrophone mounted .4 miles from the Mukilteo ferry terminal. 168 hours of constant data have been gathered between 2021 and 2024. From 1:30 am to 4:40 am, ferries don't run. Noise levels when the ferries don't run were compared to when they do run, which proved to show a significant reduction in overall RMS amplitude. Graphs plotting constant 24-hour RMS amplitude show spikes every half hour, which lines up with the Washington State Ferries (WSF) departure schedule. Future research must identify specific sound frequency signatures for the ferries and compare those frequencies and amplitudes to known values that may harm cetaceans and other marine life.

Seabirds are considered a strong indicator species for ecosystem health due to their visibility, lack of behavioral and phenotypic plasticity, and high trophic level.  Current declines in seabird populations are often attributed to bottom-up ecosystem control regulating upper trophic level populations. These bottom-up effects might be caused by reductions in marine productivity due to climate change. I performed statistical and graphical analyses on the National Audubon Society’s Christmas Bird Count data from Puget Sound and water chemistry data from the Ocean Research College Academy’s moored and deployable sensors. This allowed me to identify possible relationships between bird populations and water chemistry from 2009 to 2024 in the Possession Sound estuary. My initial analyses demonstrated the expected decline in collective seabirds counted, however certain pelagic species experienced unexpected increases. Further investigation is required to determine whether the increase was caused by ecosystem dynamics or improved count methods. My initial analyses did not indicate any relationship between water chemistry and bird populations. The lack of apparent relationship may be due to the water chemistry changes having impacts on primary productivity and indirect bottom-up trophic cascades, which could have a significant lag time in effects on bird populations. My analysis also does not account for environmental factors in disparate migration sites or breeding colonies that might affect bird populations.