Chlorophyll a derived from visual assessments plotted against chlorophyll a measured from quantitative periphyton sample collection in the same river reach
NIWA
Figure 3. Chlorophyll a derived from visual assessments (using conversion factors for the different visual assessment categories) plotted against chlorophyll a measured from quantitative periphyton sample collection in the same river reach. Data from three different observers are plotted using different symbols. The two metrics are highly correlated (R2 = 0.935). Note that derived chlorophyll a generally underestimated measured chlorophyll a at the three study sites.
