Intellectual merit Dissolved organic carbon (DOC) is a huge carbon reservoir (662 PgC), which we know little mechanistically. A significant fraction of the DOC pool (10-30%) assembles to form a nutrient-rich pool of microgels, thereby converting dispersed recalcitrant DOC to a particulate form more directly accessible to the microbial loop. We quantified DOC/gel dynamics and bioreactivity in North Pacific waters, applying a gel conceptual framework. We characterized gel assembly kinetics, annealing, and aggregation into larger gel particles, and the effects of volume phase transition phenomena related to changes in environmental parameters (pH, temperature). This work allowed us to explain DOC reactivity and dynamics in the ocean at the level of the single gel particle, measurements of DOC confound distributions and dispersion of polymer gel particles in the DOC landscape. Single-microgel analysis allows the measurement of thousands of individual particles to provide a quantitative and ultrahigh-resolution picture of transient distributions and dynamics of particles in the ocean. Broader Impacts This project has developed a user-friendly, state-of-the-art curriculum module for high school classrooms entitled Carbon's Fate: Tracing Paths through Air, Sea, and Ice. This hands-on module brings current Next Generation Science Standards (NGSS) science concepts and authentic cross-disciplinary science practices into high school classrooms nationwide. Thus, students will be exposed to science, technology, engineering, and math. Students will build the skills of critical, mathematical, and systems thinking through studying the marine carbon cycle. Students will learn to interpret complex, layered graphs with multiple data types. They will also assemble and compare data across seasonal environmental changes and geographic locations. Given these data, examples, and through our online and public software, the students will be able to answer questions about diverse ecosystems (e.g., coastal/open ocean). This curriculum will increase and broaden STEM interests, strengthen STEM identities, improve confidence in doing advanced work, and improve social capital. This education will also prepare them to be informed, scientifically literate citizens and to make educated decisions based on the science and evidence surrounding and affecting them. Last Modified: 03/21/2023 Submitted by: Monica V Orellana