An important part of addiction recovery is degrading high value associations between drug cues and the drugs themselves. Dopamine plays a crucial role in learning, and is specifically implicated in the prefrontal cortex (PFC) and reversal learning - learning to update and change behavior when it is no longer being rewarded. Past studies have reported elevations in dopamine during contingency reversal, but the timescale of how activity of PFC dopamine neurons maps to reversal learning remains unclear. Here we investigated the activity of PFC dopamine during reversal learning in a longitudinal fiber photometry study, recording dopamine signal on a timescale of seconds. Mice were trained on a reversal learning task where they initially learned that two of four presented odors precipitated a sucrose reward in 85% of the trials while the remaining two odors precipitated the reward for only 15% of the trials. Once the learning was stable, reward probability flipped for two odors (one 85% odor and one 15% odor) and the mice had to update their behavior to the new odor/reward structure. Fiber photometry recordings were conducted during pre-reversal, reversal, and post-reversal stages of the study. Our data replicate findings demonstrating elevated dopamine release during the reversal period, centered around the 15-85 cue. Analysis of the relationship between the dopamine signal and behavior also revealed significant cue, reward prediction error, and 15-85 reversal coding in the majority of animals, suggesting a multi-faceted role for dopamine in the PFC. Given this, dopamine in the PFC may play an important mediating role in the enhancement of associations between drugs and drug cues, but does not play a clear role in contingency degradation.

Escherichia coli (E. coli) abundance is commonly used to indicate water quality and environmental health. The pH of water has been shown to affect the survival of E. coli. Possession Sound is an estuary that faces a wide range of pH (around 7.5-9.0) throughout the year due to alkaline salt water from Puget Sound mixing with acidic fresh water from the Snohomish River. Primary production, organism respiration, nutrient runoff, carbon emissions, and currents also affect pH levels. This study aims to analyze the relationship between pH and E. coli abundance in an estuarine environment. PH and E. coli data was collected from 2018 to 2023 by myself and other Ocean Research College Academy students. PH data was collected with a YSI EXO2 Sonde. E. coli data was collected using a Niskin bottle to obtain water samples which were then transferred to Petri dishes for growing and counting E. coli. My preliminary analysis shows that Possession Sound’s average pH range is around 7.5-8.5, with pH being higher in spring and summer than in fall and winter. Early analysis using Spearman’s Rank Correlation suggests that pH and E. coli have a weak, inverse relationship. There is minimal research on the relationship between pH and E. coli in a marine setting, so my study helps to provide insight into the relationship between E. coli and pH in a unique estuary.

Over the last two decades, the threat of climate change has inspired significant research in the Salish Sea. Understanding trends and correlations between water temperature, dissolved oxygen (DO), and chlorophyll levels can help us understand how climate change and other anthropogenic activity has already affected the Salish Sea. My reseach focuses on seasonal and annual trends of water temperature, DO, and chlorophyll levels between 2019 and 2023 in Possession Sound, located in Everett, Washington. This longterm data-stream is generated by the Ocean Research College Academy, collected autonomously every 15 minutes by a pair of EXO sondes that are moored at Mount Baker Terminal and Everett Marina. My goal is to understand the relationship between water temperature, DO, and chlorophyll seasonally and historical trends over multiple years in Possession Sound. Preliminary figures and outside research have shown fairly consistent seasonal cycles for temperature and chlorophyll. DO trends are not as clear and data suggest significant variation is occurring within a short time frame. Future reseach may include comparing river discharge data to water chemistry data, however a more comprehensive understanding of specific inputs to the Snohomish River system is needed to draw solid conclusions about the affects of climate change.

Saltwater estuaries can experience high turbidity levels due to river input and tidal influences. Turbidity is a measure of inorganic and organic particles suspended in the water column. Reduced light penetration due to higher turbidity levels can contribute to decreased levels of primary production and the introduction of harmful pathogens to the environment. Understanding the relationship between river discharge, tides and turbidity levels could lead to a better understanding of the causes of turbidity in estuaries such as Possession Sound, WA. I hypothesize that higher current velocity contributes to higher turbidity levels. I analyzed data from a moored Acoustic Doppler Current Profiler (ADCP) and a Conductivity, Temperature, Depth (CTD) sensor located in the Everett Marina. ADCP and turbidity data were collected every 15 minutes, 24 hours a day, from 2017 to 2021. Preliminary results suggest that higher current velocity correlates to higher turbidity levels. Future research looks to discover how river discharge, tides and seasonal variance play into turbidity spikes.