First Advisor

Anne W. Thompson

Date of Award

12-2023

Document Type

Thesis

Department

Chemistry

Language

English

Subjects

Biogeochemistry, Freshwater phytoplankton, Phytoplankton populations -- Oregon -- Willamette River, Phytoplankton populations -- Columbia River, Phytoplankton -- Geographical distribution

DOI

10.15760/honors-chem.1

Abstract

As important primary producers, picophytoplankton determine the flow of carbon and energy in aquatic ecosystems. Picocyanobacteria are one picophytoplankton group known to be dominant in oceans and lakes, but they are still poorly understood in river systems. This project examined picophytoplankton communities in two distinct river systems: the Columbia and Willamette Rivers in Portland, Oregon. I aimed to characterize and quantify the picophytoplankton populations in the context of the environmental conditions of the two rivers. I used flow cytometry to detect cells based on their relative size and pigment fluorescence. I sampled nearly weekly for ten months to capture population dynamics over seasonal changes and short-duration disturbances. And finally, I discovered seven distinct picophytoplankton populations present in both rivers at varying abundances over time. My findings highlight the physiological and genetic diversity that underlie these persistent and biogeochemically important primary producers in freshwater ecosystems.

Rights

© 2023 Kylee Makenna Lamberson

This work is licensed under CC BY-NC-ND 4.0

Comments

An undergraduate honors thesis submitted in partial fulfillment of the requirements for the degree of Bachelor of Science in Chemistry: Biochemistry with Departmental Honors.

Persistent Identifier

https://archives.pdx.edu/ds/psu/41691

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