New High-resolution pCO2/TCO2 Observations Complement Long-term Hypoxia Monitoring in the Lower Columbia River Estuary

Abstract

Ocean acidification and hypoxia pose serious and increasing threats to coastal ecosystems. In the Northern California Current system, summertime wind-driven upwelling periodically brings deep, low oxygen, high-CO₂ waters to the coastal zone, where tides can transport them into the lower Columbia River estuary. These events can be stressful or lethal for marine life and have been linked to mass die-offs and shellfish hatchery losses in the region.

Long-term monitoring by the Columbia River Inter-Tribal Fish Commission’s Coastal Margin Observation and Prediction (CMOP) program has revealed recurring upwelling-driven hypoxia in the estuary each summer. However, no parallel long-term ocean acidification monitoring program has been established in this region. In spring 2024, CMOP operationalized a high-frequency pCO₂/TCO₂ analyzer2 for ocean acidification monitoring at CMOP’s Point Adams station near the South Channel of the lower estuary.

Authors

Citation

Gradoville, M.R., S. Riseman, C. Seaton, A.E. Salazar Estrada, D. Feldman, and B. Hales. 2025. New high-resolution pCO2/TCO2 observations complement long-term hypoxia monitoring in the lower Columbia River estuary. Washington Ocean Acidification Center Symposium, May 28, 2025. Seattle, WA.

Date

Report No.

Media Type