This National Science Foundation (NSF) Project Grant award under the Geosciences program (CFDA 47.050) supports a collaborative research project to understand the efficient transfer of particulate organic carbon to depth in the ocean's oxygen minimum zones. The $137,593 award, effective September 1, 2024 through August 31, 2027, will fund research to measure particle abundance, size, sinking rates, and breakdown processes in the Eastern Tropical North Pacific oxygen minimum zone. The researchers aim to test hypotheses about how low oxygen levels impact the biological carbon pump and carbon sequestration in the deep ocean. The project will incorporate new field observations into a mechanistic particle flux model to determine the key mechanisms driving efficient particulate organic carbon transfer to depth in low oxygen waters. There are no planned subawards under this grant.