Earliest hypoxic season in 20 years
Dissolved oxygen at the seafloor varies in concentration and proximity to the coast throughout the year. The Pacific Northwest waters regularly experience hypoxia in the summer but this year it started even earlier and is continuing to suffocate the waters in late September.
Jan. 1, 2021
Oxygen minimum zones are areas where the dissolved oxygen saturation in the ocean is the lowest. These areas naturally occur in waters deeper than 200 meters.
Jan. 1, 2021
Feb. 5, 2021
March 5, 2021
Shifting winds start this year's upwelling system (hypoxic offshore waters began moving inshore).
April 2, 2021
Northerly winds strengthen and observations of hypoxic water is observed in inner-shelf waters (shallower than 200 meters).
May 7, 2021
June 4, 2021
Hypoxic conditions are now persistent in the shallower inner-shelf waters.
July 2, 2021
Aug. 6, 2021
Sept. 3, 2021
Hypoxic conditions will continue until a fall or winter storm mix atmospheric oxygen back into the inner shelf waters.
Source: LiveOcean
Michala A. Garrison and Emily M. Eng / The Seattle Times