Combined sewer outflow (CSO) overflows are a threat to water quality, particularly in such urbanized areas as the Puget Sound. CSOs contribute to spills of untreated sewage mixed with stormwater that wash into water systems during heavy rain events. Possession Sound, fed by the Snohomish River, has 13 CSO outfalls in Everett, Washington, some of which experience CSO events fairly regularly. Contaminants in these CSO overflows can release pathogens, solids, nutrients, toxins, and oxygen-consuming pollutants into the water. These variables can in turn affect DO mg/L (dissolved oxygen) and turbidity NTU (measure of water clarity) – two important measures of water quality. Past research has found that wastewater spills cause major decreases in DO and increases in turbidity. DO and turbidity data were collected using a CTD in the Everett Marina throughout 2019. This data, in addition to the combined volume of water discharged from the CSOs during overflows, the duration of these spills, and the depth of precipitation in inches during the overflow, were analyzed using the Principal Component Analysis (PCA) method to find which components were most effecting the change in DO and turbidity. Using the components that covered over 90% of the variability in the data from the PCA, a Principal Component Regression (PCR) was made to be the foundation for two predictive models, one for projected DO, the other for turbidity. It is expected that a regression based on these components will make a model that covers the majority of change in DO and turbidity with a statistically significant R2 value. These models may make analysis of the effects of CSO overflows on Possession Sound a much simpler process and provide important insights into the impacts of these overflows on water quality.

Ocean acidification is a global crisis that is mainly caused by too much carbon dioxide in the atmosphere being absorbed by bodies of water, altering the water chemistry. Ocean acidification has large visual consequences, such as the bleaching of coral reefs, but less obvious, small scale influences are also found in the Salish Sea. A major indication of global warming’s effects on local water systems is pH, or the measure of how acidic or basic a solution is. Previous global studies have shown that pH has been decreasing (becoming more acidic) over the years, while the overall temperatures have been rising. The goal of this study is to observe how changes in lowernig pH are related to temperature changes in the watercolumn of Possession Sound, a salt wedge estuary, near Everett, Washington. We utilized pH and temperature vertical profiles collected from a YSI EXO Sonde, a deployment device that utilizes sensors and precise calibrations to monitor water quality, over six years to assess the degree of ocean acidification locally. Trends were analyzed according to depth and season. Preliminary studies of this particular site have shown minor changes compared to the extreme trends recorded in other ocean environments. Given the potential for negative impacts on the estuary, it is worth expanding the study by investigating a longer time frame. Local estuary data regarding depth and season will allow people to better understand how these variables change in our environment and gain a greater understanding of climate change’s influences on ocean acidification locally.

Ocean acidification, the persistent lowering of pH in marine environments, is influenced by water chemistry, biological aspects, seasonal changes, and human activity. Low pH (acidic conditions) can contribute to hypoxia, coral bleaching, and other dangerous conditions for the environment. Estuarine environments contain all these influences. In this study, changes in pH in Possession Sound, WA were examined over a five-year period, with the context of changes in river discharge. This was accomplished using a YSI EXO Sonde periodically deployed nearshore in Mukilteo, Washington, USA used in partnership with Ocean Research College Academy. This site, being within the Snohomish River Estuary, is affected by both oceanic factors and the Snohomish River, including any runoff that comes through those waters. These measurements create a depiction of changes in pH mostly due to seasonal factors, like river discharge and upwelling. Early results from these data demonstrate a clear seasonal pattern without significant annual trends toward lower pH. As climate change progresses, consistent monitoring of ocean pH will be essential to understanding the effects of ocean acidification and the ways we might combat them in the future. While this study was limited by its short timeframe, these results provide an important baseline for continued collection and analysis of these data.

Possession Sound, located in Everett, Washington, includes the second largest source of freshwater in Puget Sound from the Snohomish River. This salt-wedge estuary serves as a home to a wide selection of phytoplankton, which provide energy to a variety of organisms farther up the food chain. Water chemistry often determines where phytoplankton accumulate prior to their recycling as nutrients. Ocean Research College Academy students utilize water chemistry data (temperature, salinity, dissolved oxygen, pH, turbidity and chlorophyll concentration) from two sensors deployed in Possession Sound: One in the river and one two miles away at Mukilteo. While plankton samples are collected in the Sound, rarely are plankton collected in the river and compared to chlorophyll concentrations. This study will look at abundance and diversity of phytoplankton collected in the river at various tide stages and compare these to Mukilteo samples. I hypothesize that flood tide samples will be similar, while ebb tide phytoplankton and chlorophyll levels will decrease. The preliminary data revealed that chlorophyll and temperature levels did not vary significantly between the two sites despite the widely differing salinity levels. The next steps of the study are to determine the plankton density of phytoplankton species across the two most recent years of data. Results will enable us to explore further into plankton presence in relation to chemical variance in water systems. 

Nutrient levels in marine environments can vary widely due to local geography, the placement of various manmade input sources, seasonal factors, and tidal patterns. They are important in understanding the overall health of an ecosystem, as they can be an indicator of potential pollution. They also have a significant impact on plankton populations and, as a result, primary production. Unnaturally high nutrient levels can affect other water chemistry variables, contributing to events such as harmful algal blooms, hypoxia, and ocean acidification. In this study, I analyze 13 years of nutrient data from ten Possession Sound sampling sites, at varying distances from the mouth of the Snohomish River. Nitrate and phosphate levels were analyzed temporally, and tidal, weather, and river discharge data was overlaid to analyze the relationship between nutrients and other facets of the surrounding environment. My early analysis indicates that seasons play a large role in nutrient levels, likely due to the weather of the Pacific Northwest and runoff from the Snohomish River. Figures also support the relative similarity of values between sites, showing that nutrient levels in the Snohomish River estuary are collectively affected by nutrient flow rather than having site specific characteristics. Studies of this type can provide insight about specific characteristics of our local nutrient pathways and can provide context for changes in our ecosystem. For further research, oceanic parameters such as dissolved oxygen, pH levels, and plankton densities should be analyzed in comparison to nutrients in order to gain a better understanding of the actual relative impact of nutrients in this local marine system.

In any marine ecosystem, water currents are an important factor in both the biological aspects and the physical movements of a body of water. The focus of this study, the Possession Sound estuary in the Salish Sea, lies in an interesting area that is affected both by discharge from the Snohomish River and surrounding streams, and incoming ocean currents from the Pacific Ocean. In Possession Sound the currents can affect everything from the regular boat traffic through the area to the transportation of debris and other natural or harmful substances in the water. I used an Acoustic Doppler Current Profiler (ADCP), moored in the Everett marina at the mouth of the Snohomish River, to collect data on current velocity for 10–30-minute intervals over the period of seven months in 2020, and almost two months in 2021. The collated data I then used to analyze the current directions and speeds of the water to determine potential local trends in the currents. Preliminary analysis shows that the currents flowing near the moored ADCP tend to flow north and south with fewer currents going to the east or west. However, the currents going east and west are often faster than the north and south streams. These two trends are likely caused by the north moving ocean currents and the south moving river currents, but more research utilizing related data such as river discharge is necessary. Because of the estuary’s diverse current sources, the analysis of these data allows for a greater understanding of the movements of the water column, and insight into the transportation of important substances within it such as nutrients and heavy metals.

Harbor seals fill a critical role in the balance of the Salish Sea. Prey availability is known to be a strong indicator of seal presence; however, there are many more subtle environmental influences on harbor seal presence as well. This study hones in on the harbor seals of the Snohomish River Estuary and how their haul-out habits may be influenced by the unique water circulation of the area. This study analyzed data compiled by the Ocean Research College Academy at multiple log boom haul-out sites in the Snohomish River from 2015-2022. I analyzed seal data through the lens of the tide's movement of water in this estuary and compiled tide data from the National Oceanic and Atmospheric Administration (NOAA). I expected that there would be an increase in seals hauled-out at flood tide as well as in the beginning of the ebbing tide due to the colder temperatures experienced during high tide. Early results suggest no direct or strong correlations between tidal height and overall seal presence at sampling sites. This study seeks to better understand the presence and behavior of harbor seals at the mouth of the Snohomish River. 

Possession Sound, a fjord-type estuary system in the Salish Sea, is home not only to incredible biodiversity but also to some unique clines. A cline, such as a thermocline or a halocline, is a portion of the water column where a physical property changes significantly with depth. The haloclines of the Possession Sound fjord system vary periodically in stratification, particularly at river mouths. One such area can be found at the mouth of the Snohomish River, where cold freshwater flows into warmer seawater, creating a stratified but unstable water column. This study aims to draw connections and seek out patterns between current speeds and temperatures. Temperature data was collected from the Ocean Research College Academy's Conductivity, Temperature and Depth (CTD) sensor mooring at the Everett Marina, and current speed data was collected from their Acoustic Doppler Current Profiler (ADCP) in the same location. Prior research suggests that during most parts of the tidal cycle, temperature readings at the surface correlate strongly with tidal stages: the surface becomes colder when river water flows out to sea at low tide and warmer as the seawater pushes the river water back at high tide. However, when the tide cycle becomes less intense and current speeds decrease, this correlation becomes muddied. It is hypothesized that this pattern represents a decrease in thermocline stratification during periods of slower current speeds. Prior research done on this correlation at the mouth of the Snohomish River lacked in scope and statistical support. By expanding the scope by several months and incorporating statistical support, this study has reinforced previous findings, supporting the hypothesis posed previously: a linear correlation between the variables was supported with a p-value of 2.89E-25, and the inverse linear correlation between temperature and tide height was stronger during periods of greater average current speed.

The ability of ecosystems’ organisms to adapt and thrive is dependent on the water chemistry. One key component of water chemistry is measured by the acidity of the water, or pH. The speed of change in pH affects the ability for microorganisms to adapt and thrive. Globally, the pH of the ocean is decreasing due to increasing anthropogenic CO₂ emissions. Possession Sound, a smaller portion of the Salish Sea located off the shores of Everett, Washington, hosts a variety of organisms, all of which are affected directly and indirectly by the pH of the water. The well-being of Possession Sound was explored by examining changes in pH seasonally and spatially. Data were collected with a YSI EXO Sonde from 2016-2022 at four sampling locations with varying distances from shore and the mouth of the Snohomish River that deposits into Possession Sound. A YSI EXO Sonde is a tool used to monitor water quality with sensors to detect depth, pH, dissolved oxygen, and more. Spatially, it was found that lower pH could be found at the sites located nearer to shore. Seasonally, pH increased in the fall and winter and decreased in the spring and summer. Overall, there was less variation in the data that came from the sites located further from shore and more variation in the nearshore site. This could be attributed to the natural mixing that occurs between the freshwater influence of the Snohomish River and the ocean, along with several other factors. Future research examining pH would benefit from the addition of more data sites. Long term monitoring of the water chemistry is important because, as anthropogenic emissions increase, estuaries like that of Possession Sound will feel the effects of climate change first.

Within a marine ecosystem, eelgrass beds are critical for filtering runoff, protecting from shore erosion, and storing or absorbing excess nutrients and greenhouse gasses. Eelgrass similarly is a nursery or home for many aquatic species. Because of these connections, eelgrass has been the center of many studies as a result of its pinnacle role within the aquatic ecosystem. Within Possession Sound, located outside Everett in the southern half of the Salish Sea, eelgrass’s relationship to phytoplankton such as Pseudo-nitzschia, which is potentially toxic, is of particular interest to me. For my study, I hypothesized that the abundance of Pseudo-nitzschia will increase with increased eelgrass bed size. My study utilized data from 2015 to 2020 collected from six sites within Possession Sound. The presence of eelgrass beds and their relative size was determined through the Washington Department of Natural Resources, and plankton collection and identification were conducted by Ocean Research College Academy students. Two common species found within the eelgrass beds are Z. marina and Phyllospadix spp. Data were collected above or adjacent to eelgrass beds. I chose three plankton collection sites with differing sizes of eelgrass and three other sites with no eelgrass for comparison. I chose to monitor Pseudo-nitzschia due to its potentially harmful effects. Preliminary data indicate an association with eelgrass beds and higher Pseudo-nitzschia counts. Further research is warranted to investigate the strength of this correlation. Results will add another piece of understanding to the complex puzzle that lies within the aquatic ecosystem and another impact of eelgrass within the Possession Sound.

Plankton species tend to have a set of conditions that make certain environments ideal for that species to thrive to its highest capability. By focusing on factors such as salinity and temperature, the health of an environment can be tracked based on the consistency of those numbers and its overall impact on marine species’. Given the importance of plankton to the entire underwater food chain, understanding the ability of plankton to survive in certain circumstances is crucial to sustaining a healthy underwater ecosystem. This study analyzes data taken from various sites around Possession Sound from vertical profiles collected by students at the Ocean Research College Academy. This data was further filtered to focus only on those sample dates with abnormally high or low salinity and/or temperature levels. These numbers were compared to plankton counts to understand if the abnormalities were associated with plankton populations. The data showed a connection between days with greater salinity deviations and higher plankton counts. This may mean that salinity fluctuations have an impact on plankton density. Similar information regarding temperature is not as clear currently, meaning that there may not be as distinct of a trend.

Dissolved oxygen (DO) in the marine ecosystem is a factor that impacts not only the quality of the water but also the health of marine life. Low oxygen in the water can lead to hypoxic conditions, which are harmful and can result in the fatality of marine organisms. The levels of DO influence primary productivity and respiration. We use chlorophyll to help us reach an estimated amount of primary productivity that is in that specific area. This study took place in Possession Sound, WA, which has rich biodiversity and is a main freshwater source from the mouth of the Snohomish River. In this study, we collected profiles of DO and chlorophyll along a longitudinal transect from the field sites of Mount Baker Terminal to Buoy in Possession Sound. Looking at data like this we are able to observe what’s happening around the course of a specified tracked area, which we can then compare to areas with different parameters or in relation to other data that has been recorded. We also looked at their correlations with salinity and temperature. With this study, we are hoping to come across direct trends that circle around these parameters and that can also be relative to spatial comparisons of the sites where our data was collected. This analysis will cover comparisons from the years before and the year after 2021, to establish concrete conclusions supported from the data over time. Learning about the DO qualities impacting organisms will allow us a further understanding of the health and productivity occurring in the ecosystem of the Possession Sound.

During the 2019/2020 recreational crab season, the Washington Department of Fish and Wildlife reported over 735,000 pounds of legal Dungeness crab harvested in Possession Sound and the Strait of Juan de Fuca. This enormous fishery relies on numerous variables to survive, including the essential factor, dissolved oxygen. Low levels of dissolved oxygen can lead to an increased risk of disease and suffocation for crabs during all stages of life. When dissolved oxygen levels drop below 2 mg/L, crustaceans, including crabs, do not have enough oxygen to survive. This is called hypoxia. While parts of Possession Sound have rarely had any recent experiences with hypoxia, research conducted by students at the Ocean Research College Academy (ORCA) indicates that levels of dissolved oxygen in Possession Sound have recently decreased. My research indicates this trend has been observed, along with an increase in the average annual temperature of Possession Sound, which can contribute to low dissolved oxygen levels. The connection between well-established historical trends of increasing ocean temperatures could introduce more concerns for shellfish such as crabs. My study explores the presence and abundance of crab zoea in Possession Sound and compares these data to trends of dissolved oxygen and temperature in Possession Sound over a 7 year period (2015-17 and 2019-2022). Dissolved oxygen data was monitored with YSI and EXO sensors while crab zoea were counted by my colleagues and I at ORCA. My research seeks to establish a correlation between dissolved oxygen and the presence of crab zoea that could be a critical tool in the management and prediction of future crab populations in this critical crab habitat.

The brain maintains body weight homeostasis via a tightly regulated neuronal circuitry. Microglia, the innate immune cells of the brain, elicit an inflammatory response that triggers increased food intake and weight gain on a high fat diet. We are curious how microglia regulate the neuronal circuitry to affect food intake and body weight. We have developed a chemogenetic mouse model that expresses a modified Gs-protein-coupled DREADD (Designer Receptor Exclusively Activated by Designer Drugs) selectively on microglia. Administration of the ligand Clozapine-N-Oxide (CNO) activates the cyclic AMP signaling cascade in microglia. We have found that CNO administration for three days increases the cytokine IL-1𝞫, and reduces chemotactic signals (P2RY12 and CCL3) and Agouti-Related Peptide (AgRP). AgRP is produced from neurons in the hypothalamus and is responsible for feelings of hunger. I hypothesize that microglial Gs-DREADD activation suppresses AgRP signaling and reduces food intake and body weight. To test this hypothesis, mice expressing the microglial Gs-DREADD (MG Gs-DREADD+) and control littermates (MG Gs-DREADD-) will receive daily intraperitoneal administration of CNO (1 mg/kg), and will be monitored for food intake and body weight for a week. Mice will then be placed on a high fat diet (60% kcal obtained from fat) under daily CNO administration, and will be monitored for food intake and body weight gain for 4 weeks. I hypothesize that MG Gs-DREADD+ mice will show reduced food intake and weight gain on a HFD when compared to MG Gs-DREADD- mice. At the end of the study, I will examine changes in inflammatory mediators and neuropeptides in the hypothalamus of the mice. Overall, this study will help elucidate how microglia alter hunger and satiety signals in the brain to regulate appetite and body weight. Moreover, the ability to modify these signals can help individuals manage their weight and prevent obesity.
 

Photosynthesis and organic matter production by photoautotrophs in the upper ocean are fueled by sunlight. In previous research, environmental metabolite concentrations in the sunlit ocean have been found to display significant 24-hour periodicity. Prochlorococcus is a marine cyanobacteria that is the smallest and most abundant photosynthetic organism on Earth and is a key primary producer in the ocean’s vast oligotrophic gyres. Past studies employing transcriptomics and flow cytometry-based approaches revealed that cell division, metabolism, and gene expression of Prochlorococcus are synchronized with the daily light-dark cycle, but the impacts of these diel changes on the Prochlorococcus metabolome remain poorly understood. Here we investigate how levels of particulate metabolites in Prochlorococcus vary over simulated light-dark cycles in a non-axenic culture. We grew Prochlorococcus MED4 and its associated consortium of heterotrophic bacteria over daily light-dark cycles in culture and sampled for particulate and dissolved metabolites every 6 hours for a total of 48 hours. We extracted metabolites using a modified Bligh and Dyer extraction and quantified metabolites using liquid chromatography paired with mass spectrometry. To detect diel patterns in metabolite concentrations, we used Rhythmicity Analysis Incorporating Nonparametric methods to identify significant changes in Prochlorococcus’ metabolome over the light-dark cycle. Sucrose, a disaccharide sugar, varied over the diel cycle and peaked at the end of the light cycle, highlighting the use of this compound for energy storage in Prochlorococcus. Glutamine, a metabolite associated with nitrogen assimilation, displayed diel variation and peaked at midnight, lagging the peak in sucrose by 6 hours. These results indicate diel partitioning of Prochlorococcus’ metabolic functions related to energy storage and nitrogen assimilation. This diel partitioning mirrors prior results observed in environmental metabolomes and transcriptomes.