Hypoxia occurs when an area of the ocean has insufficient dissolved oxygen to support most marine life. When oxygen levels plummet, most animals suffocate if they cannot escape. Hypoxic areas are thus often termed “dead zones”. Since 2002, hypoxic waters have appeared and recurred during the summer along the coastal fringes of the northern California Current Large Marine Ecosystem (off Oregon and Washington). For in-depth information, see Frequently Asked Questions (63 KB, *.pdf). Research using over 50 years of oceanographic information is now showing that prior to 2002, these events were completely unprecedented. Hypoxia is closely linked to shifting wind patterns and changing ocean conditions. Scientists believe that hypoxia in these coastal ocean waters is becoming the “new normal” during the summertime.
Photos of research during hypoxic events off the Oregon Coast
Researchers tracked the most severe hypoxic event yet recorded in Oregon’s coastal waters in 2006. Oxygen levels fell to zero for the first time on record. (‘Anoxia’ is the term used to mean ‘no oxygen.’) This sudden change had broad ecological impacts. Using a robotic submersible, PISCO researchers and biologists from the Oregon Department of Fish and Wildlife revealed the disappearance of fish and mass die-off of many bottom-dwelling marine organisms in near-shore rocky reef habitats. Monitoring efforts by NOAA scientists further indicated the presence of severely low oxygen water along much of the Oregon and Washington coasts.
In response to this recent rise of hypoxia and anoxia in nearshore, shallow waters, a new network of researchers now monitors the coastal ocean off Washington and Oregon to track the appearance and consequences of hypoxia. This ocean-observing effort involves both research vessels and new state-of-the-art moored oceanographic sensors and autonomous underwater vehicles called "gliders" that patrol the coastal ocean around the clock. In 2007, this monitoring effort detected the reappearance of near-shore severe hypoxia along the Oregon coast.
Ocean areas from southern Oregon to northern Washington were surveyed in 2007 with collaborations across academic institutions and governmental agencies (PISCO, NOAA Fisheries, Oregon Department of Fish and Wildlife, and NOAA Olympic Coast National Marine Sanctuary). The central Oregon coastline, near Newport, was the focus of intense oceanographic and ecological studies. A large number of Remotely Operated Vehicle (ROV) surveys documented the ways in which rocky reef fish and other marine life recovered from the severe 2006 event and responded to 2007 hypoxia. Frequent surveys in summer 2007 showed that, as the dead zone receded, fish species moved back onto the reefs. For long-lived and less mobile bottom-dwelling marine life, scientists have continued to see long lasting impacts from the 2006 event. Continued research will be essential for charting the long term course of recovery for these ecosystems.
Surveys showed partial recovery of a few species and continued depression of others. The process of ecosystem recovery from the extreme 2006 event was likely compromised by the return of hypoxia in 2007. Researchers suggest that recurring hypoxia may create long-lasting changes to the ecosystem.
Research is underway to monitor changes and to understand the causes and consequences of these hypoxic events.
Policy and Outreach
Interest in hypoxia has escalated rapidly as the extent of the event has grown. Local, state, and federal researchers and agencies consider the consequences and how to plan in the future. PISCO scientists and policy coordinators have engaged in a wide variety of activities to help inform these processes.
Selected press:
Oregonian: 2/15/08 (23KB, pdf)
Press release: 2/14/08 (128KB, pdf)
Oregonian, 8/1/07 (22KB, pdf)
Seattle Times, 7/31/07 (22KB, pdf)
for more information: hypoxia@science.oregonstate.edu) at 541-737-8645
The Science of Hypoxia
Unlike the dead zones in estuarine systems that are caused in large parts, by excessive nutrient run-offs from land, the Oregon dead zone forms along the open coast where coastal winds drive ocean currents that upwell nutrient-rich but oxygen-poor waters from the deep sea onto the shallow reaches of the continental shelf. This upwelling of nutrients further fuel phytoplankton blooms that eventually sink and decompose to further reduce oxygen levels in the already low oxygen waters along the seafloor. Hypoxic zones along the Oregon coast forms seasonally, and can begin in late spring/early summer in response to the onset of upwelling-favorable winds from the North. Hypoxia can persist through the summer months and ultimately recedes for the year during the Fall when winds again shift direction and promote ocean currents that flushes low oxygen water off the continental shelf.
Upwelling-caused dead zones have their greatest impacts on the shallow waters of the continental shelf where extremely low oxygen conditions are not a typical feature. The 2006 dead zone encompassed over 3000 km of the Oregon shelf, an area that exceeds the total combined area of estuaries in the state. Recent reports have also indicated the possible novel development of an analogous dead zone along the open coast of Washington state. Since upwelling shelves represent the one of the largest fraction of coastal marine waters of the US west coast, uncertainties into the potential for further intensification and expansion of upwelling-driven dead zones represent a major scientific and management challenge.
Researchers and Collaborators
- Other researchers include:Libe Washburn (PISCO/UCSB), Margaret McManus (PISCO/UCSC/University of Hawaii), John M. Bane (University of North Carolina), Karina Nielsen (Sonoma State University) and Stephen Pierce (OSU).
- Primary collaborator is Oregon Department of Fish and Wildlife's Marine Habitat Program (ODFW). ODFW owns and operates the Remotely Operated Vehicle (ROV). Dr. Dave Fox oversees this program.
Monitoring and Evaluation
PISCO scientists are involved in studies to monitor hypoxia off the Oregon coast. Researchers are currently tracking the position and duration of the low-oxygen water, developing models to help understand and predict its occurrence, testing new instruments designed to provide near-real time measurements of ocean conditions, and evaluating the likely long-term impacts of the hypoxia.
Selected PISCO Publications and Resources
Outreach resources:
Photos of research during hypoxic events off Oregon Coast
- Video: footage of Cape Perpetua in 2001 under normal conditions (30 seconds). Followed by footage of Cape Perpetua in 2006 during hypoxic conditions (30 sec). Format: avi mov mp4 h264
- Archive:
PISCO Peer Reviewed Papers
- Chan, F., J. A.Barth, J. Lubchenco, A. Kirincich, H. Weeks, W.T. Peterson, and B. A. Menge. 2008. Emergence of Anoxia in the California Current Large Marine Ecosystem. Science 15 February 2008 vol 319. www.sciencemag.org
- Grantham, B. A., F. Chan, K. J. Nielsen, D. S. Fox, J. A. Barth, A. Huyer, J. Lubchenco, and B. A. Menge. 2004. Upwelling-driven nearshore hypoxia signals ecosystem and oceanographic changes in the northeast Pacific. Nature 429:749-754.
- Barth, J.A., B.A. Menge, J. Lubchenco, F. Chan, A. Kirinich, L. Washburn, M. McManus, J. Bane, K. Nielsen, and S. Pierce. Delayed upwelling alters nearshore coastal ocean ecosystems in the northern California Current. Proceedings of the National Academy of Sciences USA 2007 104:3719-3724.
→ See Master Citation List for all PISCO Scientists
Other Peer Reviewed and Technical Papers
Glenn,G., R. Arnone, T. Bergmann,W.P. Bissett, M. Crowley, J. Cullen, J. Gryzmski, D. Haidvogel, J. Kohut, M. Moline, M. Oliver, C. Orrico, R. Sherrell, T. Song, A. Weidemann, R. Chant, and O. Schofield. 2004. Biogeochemical impact of summertime coastal upwelling on the New Jersey Shelf. Journal of Geophysical Research. 109. C12S02, doi:10.1029/2003JC002265
Buck, Eugene. Marine Dead Zones: Understanding the problem. CRS Report for Congress, Nov 2006.
