OCEAN HEALTH
Dissolved Oxygen (open water) (DO)
Oxygen available to marine life. Falling DO is the signature of nutrient pollution and warming; sustained hypoxia is a dead-zone alarm.
Threshold Bands
| Band | Range | State |
|---|---|---|
| Healthy | ≥ 6 | OK |
| Hypoxic-risk | 4–6 | WARN |
| Hypoxic | < 4 | CRIT |
Formula
Optical-sensor dissolved O₂, temperature- and salinity-corrected.