Fig. 4: Decadal time series of DO concentrations in spring.
Annual median bottom-water oxygen concentrations in the first 3 weeks after ice-off by logarithmic lake surface area class. GAM smooths were weighted by inverse variance to account for uncertainty at low sample counts. Shaded areas represent 95% CIs. Legend labels define area class boundaries (for example, green marks Asurf = 102–103 ha). Dashed and dotted lines mark hypoxia (DO < 2 mg l−1) and anoxia (DO < 0.5 mg l−1), respectively.
