Ocean acidification is the reduction of pH in seawater due to increased carbon dioxide from fossil fuels in the atmosphere and other anthropogenic factors. Ocean acidification causes shellfish such as oysters to experience difficulty building their shells. Acidification trends in the North Pacific Basin are well documented, yet pH trends in Possession Sound, a salt-wedge estuary located in the Salish Sea is less documented. Possession Sound receives discharge from the Snohomish River and has human activity along the shoreline. In this study, the average change of pH in the middle of the North Pacific Ocean was measured and compared to the average change of pH in Possession Sound since 2016. I analyzed data collected from ARGOS Floats located in the central North Pacific Ocean. For Possession Sound, I used data collected from a  YSI EXO Sonde in partnership with the Ocean Research College Academy (ORCA). I collected data on 12 research cruises in 2024. I expect to find a slightly greater decrease in pH within Possession Sound than the North Pacific Basin due to the additional anthropogenic factors present in the Sound. Preliminary analysis shows a slight seasonal change in pH in Possession Sound, but little to no change yearly. I expect the data to show a steady decrease in pH for Possession Sound and the North Pacific Ocean basin every year since 2016. Calculating acidification rates and learning how they differ in various geographical locations, with separate factors, will increase understanding of the impacts of ocean acidification, which may be used in conservation efforts. 

Possession Sound, located between the city of Everett and Whidbey Island, is a part of both a key economic area and a bustling marine environment. Because of the marine activity, scientists study all sorts of parameters involving the water including noise. Numerous studies have assessed ambient noise in marine environments to investigate the influence of tidal forces on ambient noise. These reports found that tidal noise or “flow noise” is observed around the 0-100Hz range with the most significant impacts observed centered around 25hz. The Ocean Research College Academy operates a SoundTrap ST400 STD hydrophone mounted to Mount Baker Terminal that takes recordings daily for most of the year. Mount Baker Terminal is a small marine terminal operated by the Port of Everett, located just north of the town of Mukilteo. Using data collected from the hydrophone, I took measurements of ambient noise in root mean square amplitude centered around the 25hz range and compared that to NOAA tidal data at Everett, Washington. Using these data I investigated the potential presence of a relationship between the tides and ambient noise. When the initial measurements of root mean square amplitude were compared to tidal data from the area the results showed that tides had no significant impact on the ambient noise at Mount Baker Terminal. Investigating the effects of tides on ambient noise can be crucial to future acoustic research done by researchers in the area as results could be affected by noise created or affected by tides. Future analysis should investigate the impacts of other natural contributors to the soundscape such as rain and wind.

Harmful algal blooms (HABs) are threats to a number of species in marine environments. One hypothesis states that excess nutrients in water lead to accumulations of certain plankton species that produce toxins. This can explain some illnesses such as paralytic shellfish syndrome in humans who consume impacted shellfish. HABs can be identified directly, but given the delays involved in analyzing results, other indicators may be used to predict presence of HABs as well. Possession Sound is an inlet of the Puget Sound located between Whidbey Island and the coasts of Everett and Mukilteo, Washington, connecting to the Snohomish River, as well as Saratoga Passage and Port Susan to its North and the main Puget Sound basin to its South.  Since HABs can occur in freshwater and saltwater for different reasons, Possession Sound’s status as a salt-wedge estuary makes it notable as a study site. To investigate the nature of HABs in Possession Sound, I analyzed plankton density data, chlorophyll-a levels, and phosphorus concentration data I collected in 2024 as well as data collected by the Ocean Research College Academy from 2016-2024. Chlorophyll-a concentrations were measured with a YSI EXO Sonde. Phosphorus concentrations of water samples were collected using a Niskin bottle and measured by the University of Washington Marine Chemistry Lab. I analyzed the progression of each parameter temporally and spatially. I expect to see clear spikes in certain plankton species, especially dinoflagellates, that align with similar-timed chlorophyll-a and phosphorus spikes. However, I predict that trends will be the least prominent in phosphorus concentrations due to its greater prevalence in freshwater than in saltwater. Understanding which plankton species are most responsible for HABs and temporal alignment of potential drivers can allow for better prediction of HABs in Possession Sound.

The Eastern North Pacific gray whales (Eschrichtius robustus) have a long migration from their breeding grounds in Mexico to their feeding grounds in Alaska. A subgroup of the Eastern North Pacific stock, nicknamed the Sounders, deviate from the migratory path most gray whales follow to feed in the Salish Sea, typically between the months of March and May. Other studies show that gray whales feed on benthic organisms such as ghost shrimp. Studies conducted in the Arctic area of the gray whale migration route have seen sea ice playing an important role in the gray whales being able to enter the areas where they feed. One working hypothesis is that gray whale shifts in migration patterns are the direct result of climate change; this could explain why some of the Eastern North Pacific gray whales enter and feed in Possession Sound. I analyzed sightings data, shared by the Whale Museum and recorded in Possession Sound, WA from 2000-2022. These data, most of which were compiled by the Orca Network, were filtered to identify the number of visitations each month over the study period. Early analysis shows a phenological shift in the time of the gray whale's arrival and departure from Possession Sound. The shift shows an increase in the number of months gray whales are present in Possession Sound, from a March to May visit to a year-round presence. Although these results cannot explain the reason for the phenological shift, future research must look into related shifts in the Arctic ice formation as well as ambient air and water temperature shifts. Future research calculating density of ghost shrimp in Possession Sound will also indicate why this location is favored.

The King County Brightwater Treatment Plant includes a marine outfall pipe anchored to the seafloor that discharges highly treated effluent from the Seattle metropolitan area into Puget Sound, Washington. Since 2009, as part of an eelgrass survey study, King County biologists have collected annual video footage of the outfall pipes from which they witnessed the abundance of organisms colonizing the pipe at all depths. Consequently, in 2012, King County biologists launched a ten-year project assessing the effectiveness of the high-density polyethylene (HDPE) outfall pipe at providing habitat for marine organisms and the composition of organisms it houses. Using a  remotely operated vehicle (ROV), they placed thirty plates of HDPE material adjacent to the outfall pipe at 100ft, 300ft and 600ft depths. Sets of replicate plates were then retrieved after 2, 5, and 10 years of deployment, at which time King County staff immediately took photos of each plate for analytical assessment. In this study, we analyzed the photos for percent live cover and composition of marine organisms inhabiting the pipe material, all across depths and time intervals. We hypothesized that the wastewater outfall pipe can function as a habitat; and the extent to which different organisms, their identifications and abundance, likely vary by depths due to the environmental conditions at different levels of depths. We found that percent live cover increased over time but did not vary across depths, and that certain phyla consistently dominated cover on the plates but dominant groups varied across depths. These findings allow experts in the field to consider using outfall pipes to provide additional habitats for marine organisms, and to assess communities of organisms at depths that are less accessible. 

Zostera marina (eelgrass) is one of the many important biological features of Possession Sound, acting as a substrate for many microorganisms, a filter of greenhouse gases, and as protection for many species. The Possession Sound has been marked as a Seagrass Sanctuary by the Department of Natural Resources, which protects and monitors nearshore eelgrasses within the basin. By looking at what kinds of species are found in a marine environment, researchers can assess an ecosystem's overall health. Environmental DNA (eDNA) is a data capture technique used by researchers that picks up DNA traces left behind by organisms, and shows their presence/absence in a given area. The study site, Mount Baker Terminal, lies inside the Possession Sound basin near Everett, Washington, and contains a large eelgrass bed. I collected 10 samples using passive filters submerged at various depths inside and outside the eelgrass bed in 2024 and processed at a WDFW lab. I analyzed these data and 40 additional samples collected by the Ocean Research College Academy from 2021-2024 using similar methods. I hypothesized that there would be more species such as crustaceans, fish, and other plants inside the eelgrass because of its ability to protect and maintain a nutrient-dense environment. These data will help shed light on species richness in each environment, which has potential implications for understanding the overall health of the ecosystem and the critical role eelgrass plays in the estuary.