Along the shoreline of Possession Sound, located in the southern basin of the Salish Sea are 10 outflows of combined sewage systems. Combined sewage systems collect rainwater, untreated domestic sewage, and industrial wastewater within a single sewer line. When heavy rainfall occurs, these systems overflow and are directed into designated combined sewage outflows (CSOs), which then empty into the estuary, releasing E. coli (Escherichia coli) directly into the estuarine ecosystem. These CSOs, along with other factors, change the pH of the waters within the basin. Preliminary analysis of primary literature suggests a relationship exists between pH and E. coli growth. The pH change affects the enzyme growth within E. coli. As river discharge fluctuates, so does the amount of outflow from the CSOs which then cascades into pH changes at the site closer to the CSOs. The guidelines and regulations in place today allow for significant volumes of sanitary waste to be overflowed into marine systems. When river discharge increases, the overall pH within the Sound decreases. It was hypothesized that when there is a large amount of rainfall that leads to heavy river discharge and low pH, there will be more Escherichia coli growth at all of the sites throughout the Sound. Ocean Research College Academy students collected bacterial sample data at 12 stations in Possession Sound from 2009 to 2019. All data were recorded with distance from a CSO. A Niskin bottle was deployed at the surface and halocline with a YSI 650 testing pH. Samples were tested for bacterial count and compared with other samples taken after heavy rainfalls. Further research will define the trends in river discharge, pH and E.coli for Possession Sound.

Eelgrass beds in central Salish Sea are critical components of healthy ecosystems that are vulnerable to anthropogenic impacts. This study utilized two locations in Possession Sound to monitor water chemistry within and near two different eelgrass beds; one unmapped, and one established. The study compared these two locations and investigated the impact of location on water chemistry within the bed. Data-sharing and collaboration with the Samish Indian Nation Department of Natural Resources’ work on eelgrass beds in Fidalgo Bay provided a broader scope into regional differences within the central Salish Sea. This study was conducted by Ocean Research College Academy (ORCA) students at eelgrass beds in Possession Sound located near Mukilteo and Hat Island. The study ran from October 2019 to spring 2020, and utilized background data from past studies to inform studies at the bed near Mukilteo. Data were collected using a combination cast of a camera collecting visual data and a CastAway CTD, which collected vertical profiles of salinity and temperature at recorded geographic coordinates. Data were collected during a free drift across the eelgrass bed. An EXO Sonde was temporarily installed in the bed to collect chlorophyll and turbidity data in a longitudinal manner. The study primarily explored how location impacts the water chemistry eelgrass beds in central Salish Sea both within the bed and within a region. Research going forward could study remote beds more comprehensively using technology previously tested such as drones and SONAR, as well as a longer-term collaboration between the Samish DNR and ORCA.

As climate impacts are amplified in the nearshore regions, the Possession Sound located near the heart of the Salish Sea is a key study area of the local marine ecosystem. Systems such as these are very sensitive to fluctuations in temperature. For example, in 2015, “The Blob,” which was a massive body of abnormally warm water that ranged from California north to Alaska, raised salinity and lowered DO causing high mortality rates in a range of taxa. Events such as these are referred to as Marine Heat Waves (MHW). In 2019 analysis of satellite thermal imagery data concluded that another Marine Heat Wave had struck the West Coast displaying temperatures reaching as high as seven degrees Fahrenheit above average. Additionally, parts of the Salish Sea have observed some possible influence of the MHW from the Pacific. In order to determine the localized impact of these Marine Heat Waves, I used data from a fixed CTD probe from the Ocean Research College Academy were analyzed, focusing on parameters temperature, salinity, and dissolved oxygen. I hypothesized that there is a delay of increased temperature from the Pacific due to possible mixing of coastal currents traveling through the Juan de Fuca Strait into the Salish Sea. When exploring this data set, I have found that since 2009 average water temperatures have risen, 2019 average temperature is .4 degrees higher than in 2009, with 2015 having a peak temperature average of 11.5 degrees Celsius, 1.1 degrees higher than 2009, which aligns with “The Blob” of 2015. Trends have shown an increase in average temperature since 2009, with MHWs event being a prevalent factor in rising average temperatures, and lower dissolved oxygen averages.

During September and October, endangered Olive Ridley sea turtles have been observed swimming up onto the beaches of Salinas Grandes, Nicaragua to nest. Literature has identified different environmental factors that affect sea turtle nesting activity. This study compared moon phase, lunar illumination, and tide height to the number of nests observed. The data for these factors were collected by tides4fishing, a company that collects data on tides, solunar activity, moon phases, lunar illumination, and fishing sites in North and Central America. Data for the number of nests, along with the time of night they were counted, were provided by Turtle Tribe, a sea turtle conservation project run by a non-profit called Water and Light International in Salinas Grandes, Nicaragua. I partnered with Turtle Tribe to use their data for conducting research that could aid in future conservation efforts; I even collected some nest data myself when I traveled to Nicaragua. It was hypothesized that the greatest number of nests would occur when there is the least amount of lunar illumination and at a high tide level. The limited light could act as protection for the sea turtles from predators and the high tide would allow them to walk farther up the beach where the nests are not in danger of being drowned by the tide. Least-squares regression analysis was performed to check for correlation between these factors. The hypothesis was not supported by these data. More data are needed to conclusively determine whether there is a correlation between these environmental factors and the number of Olive Ridley sea turtle nests. Additional years of data and environmental factors such as the steepness of the beach would be useful.