Data collected by NOAA has confirmed that a large area of poorly oxygenated water is growing off the coast of Washington and Oregon in the US, threatening to create ‘dead zones’ where bottom-dwelling species perish.
Oxygen-depleted bottom waters, known as hypoxia, occur seasonally but measurements collected by NOAA researchers and from commercial fishermen, show the earliest start to the phenomenon for 35 years.
“Low dissolved oxygen levels have become the norm in the Pacific Northeast, but this event started much earlier than we've seen in our records,” said Oregon State University Professor Francis Chan, director of the NOAA cooperative institute CIMERS.
The West Coast Ocean Acidification Cruise on board the Ronald H. Brown left port on 13 June for its 45-day mission sampling along several transects from British Columbia to California. Supported by the NOAA Ocean Acidification Program, this recurring scientific cruise surveys ocean conditions to better understand the factors that influence ocean acidification and hypoxia, which are related.
Returning to port, Richard Feely, an oceanographer with NOAA’s Pacific Marine Environmental Laboratory, said that dissolved oxygen and ocean acidity measurements have the potential to create the dead zones later this summer.
Beachgoers have been reporting large numbers of crabs washing ashore in Ocean Shores in Washington earlier this year in May and Professor Chan reports that the last time scientists observed an event this strong was in 2006 when a large dead zone wiped out crabs and other bottom-dwelling marine life along the continental shelf.
