A 13-year temporal and spatial analysis of nutrient levels in Possession Sound and their seasonal relationship with river discharge

• Main Author: Kim, Sheamin
• Format: Text
• Language: English
• Published: Western CEDAR 2022
• Subjects: Pacific; Ocean acidification
• Online Access: https://cedar.wwu.edu/ssec/2022ssec/allsessions/57; https://cedar.wwu.edu/context/ssec/article/3219/viewcontent/63_12bd1e91b49a42958e920dd19186ae50.pdf

Nutrient levels in an estuarine environment vary widely over geography and various input source points. They are important in understanding the overall health of an ecosystem due to their impact on primary production. The combined effects of seasonal changes, tidal patterns, and local manmade nutrient sources can cause nutrient levels in an estuary to vary. Unnaturally high nutrient levels can affect other water chemistry variables, and contribute to events such as harmful algal blooms, hypoxia, and ocean acidification. This study presents 13 years of nutrient data and analysis from three different sites in Possession Sound. Each site was analyzed for nutrients levels, chiefly nitrate values measured at the surface, but also including phosphates, nitrites, ammonium, and silicates. Figures isolating individual correlations, such as season, site, depth, and river discharge were analyzed to understand the nutrient dynamic within the wider ecosystem. 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. 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 pH levels and plankton densities should be analyzed in comparison to nutrients in order to gain a better understanding of the relative impact of nutrient levels.