Award: OCE-1847687

Understanding the role of the ocean in the nitrogen cycle Our project aimed to explore how small-scale ocean currents influence the nitrogen cycle in regions of the ocean known as Oxygen Minimum Zones (OMZs). These are areas where oxygen levels are extremely low, affecting marine life and global climate processes. Specifically, we wanted to understand how ocean currents, including oceanic eddies, impact the movement and transformations of nitrogen compounds, including nitrous oxide (N2O), a powerful greenhouse gas that contributes to warming the atmosphere. Our key scientific findings consist of: Discovery of submesoscale coherent vortices (SCVs): We developed a method to detect small, swirling ocean currents called SCVs using data from over 20 years of ocean-monitoring floats. Identifying around 4,000 of these vortices globally, we found they play a significant role in transporting materials across the ocean, especially in critical regions like upwelling systems. Improved estimates of oceanic N2O emissions: By applying machine learning techniques to a vast dataset of 158,000 N2O measurements, we generated more accurate global maps of N2O emissions from the ocean to the atmosphere. This work reduces uncertainty in greenhouse gas budgets and helps better predict future greenhouse gas emissions. Development of a new nitrogen cycle model: We developed a new computer model that simulates how different forms of nitrogen transform in OMZs, which can be incorporated in complex climate models. This model helps us understand the interactions between chemical compounds in low-oxygen environments and can be used to predict how these zones respond to environmental and climatic changes. Impact of ocean eddies on nitrogen loss and N2O production: Our research showed that small-scale ocean currents, such as eddies, can increase the loss of nitrogen-based nutrients in OMZs, while also reducing the production of the greenhouse gas N2O. This highlights the importance of considering fine-scale physical processes in global ocean and climate models. Our broader impacts consist of: Educational outreach and student involvement: We integrated an ocean-going research experience into an undergraduate course at UCLA, with over 85 students each year participating in boat trips to collect and analyze oceanographic data. This initiative enhanced learning and inspired students to pursue careers in ocean sciences, with many students joining research projects and continuing to graduate school. Global collaborations and data sharing: We participated in international scientific collaborations and contributed to global assessments of greenhouse gas emissions from the ocean. By sharing our models and datasets, we supported other scientists in their efforts to understand ocean chemical cycles, greenhouse gas emissions, and their importance for climate. Last Modified: 11/18/2024 Submitted by: DanieleBianchi