How much habitat has sufficient oxygen?
This metric shows the thickness of the water column at a given location that is hypoxic (orange area) or potentially stressful (purple area). Also shown are the long-term averages (lines) for the data series. If the colored area is above the similarly colored line, that means there is more low oxygen water than average. Read More
Water is habitat for organisms like fish and plankton. The amount of oxygen available to such organisms varies by location and time. This metric quantifies the amount of water column habitat for two different oxygen ranges: hypoxic: DO < 2 mg/l, and potentially stressful: DO < 5 mg/l. Tracking this amount can illuminate when and where in Puget Sound potential ecological impacts may occur.
The habitat volume change is presented as a total layer thickness of water, despite where in the water column it occurs, at UW/NANOOS ORCA mooring sites. This thickness, when compared to the total water depth at a location, can also be viewed as a percentage of the water column. Both measures (thickness and percentage) are useful for understanding the potential ecological impacts of changes in dissolved oxygen concentration. This metric also compares the mooring observations to a climatology formed from these historical records.
Bar graph indicating the water thickness of low dissolved oxygen (DO) water as a function of time for both 5 mg/l (purple) and 2 mg/l (orange) limits for the 6 ORCA buoys in Puget Sound. The corresponding low DO water as a percent of the full-depth water column is shown on the right y-axis; the bottom depth for each buoy is noted above each panel. Average low DO taken over the full buoy time series (n years noted above each panel) is shown as the climatology for both the 5 mg/l (dark blue line) and 2 mg/l (red line) limits. The vertical black line shows the date of the most recent plot update. Data to the right of the black line are from the previous year and shaded lighter for both 5 mg/l (light purple) and 2 mg/l (light orange) to denote the change in time.
