Figure 3

Correlation between spectral features and spatial distribution. Principal component analysis was done for each algal cell separately. Left: PC score images over time (gray indicates the background); right: PC loadings. The percentages on each loading shows the average of the percentage of the total variance explained by each principal component along the replicates of the experiment. Colored vertical bands indicate chemical compounds: orange: carbohydrate, green: DNA–RNA, gray: amide II, blue: lipids; “LtoH” indicates the low (390 ppm CO₂) to high (5000 ppm CO₂) treatment. “HtoL” indicates the high (5000 ppm CO₂) to low (390 ppm CO₂) treatment.