Please join us this Friday, October 30, for our weekly MEAS seminar featuring our very own Dr. Katelyn Gray!
Seminar Pre-Reception: 3:00 PM | Jordan Hall, Room 1214
Seminar: 3:30 PM | Jordan Hall, Room 1216
Speaker: Dr. Katelyn Gray
Hosted by: Dr. Ethan Hyland
Seminar Title: Phosphorus Cycling in the Past, Present, and Future
Abstract:
The overapplication of nutrients in modern agriculture has improved food security but at a significant environmental cost. In coastal regions worldwide, excess nutrients from agriculture stimulate primary production, and the resulting increase in microbial degradation of organic matter depletes oxygen in the water—a process known as eutrophication. Unfortunately, climate change and human activities are expanding the temporal and spatial extent of eutrophication-driven oxygen depletion.
Eutrophication has occurred on a global scale numerous times throughout Earth’s geological history. Ocean Anoxic Events (OAEs) were major environmental disturbances characterized by enhanced organic carbon burial and changes in sedimentary carbon isotopes (δ¹³C), temporally linked to increased atmospheric carbon dioxide concentrations and global temperatures. Despite nutrient surpluses driving eutrophic conditions during these events, Earth’s oceans eventually returned to oxygenated conditions.
Phosphorus (P) is a key limiting nutrient for investigating eutrophication during OAEs. The primary input of phosphorus to the oceans comes from the riverine delivery of weathered continental rocks and soil, while its primary output occurs through sedimentary burial. Both fluxes can change over geological timescales. Tracking phosphorus sources and sinks during OAEs is essential for understanding how major shifts in biogeochemical cycles lead to nutrient surpluses, enhanced primary productivity, and oxygen depletion—even in the absence of human activity. This knowledge can also help us develop innovative approaches to removing excess nutrients in regions affected by eutrophication, prevent unsustainable agricultural practices, and establish effective nutrient management plans for the future.