Figure F20. A. Sequential depth plot of raw reflectance spectra for Site 1239. B. First derivatives of raw reflectance data with respect to wavelength. Red lines = absorption features typical of organic pigments (e.g., at 410, 510, 560, and 650 nm). C. The normalized absorption feature at 650 nm, relative to reflectances at 630 and 700 nm and normalized to a measure of the general slope of the spectrum (i.e., Depth650 = {R630 + [3/7 x (R700 - R630) -R650]}/[R700 - R400]), is plotted with depth as a proxy for abundance of chlorins.

Figure F20. A. Sequential depth plot of raw reflectance spectra for Site 1239. B. First derivatives of raw reflectance data with respect to wavelength. Red lines = absorption features typical of organic pigments (e.g., at 410, 510, 560, and 650 nm). C. The normalized absorption feature at 650 nm, relative to reflectances at 630 and 700 nm and normalized to a measure of the general slope of the spectrum (i.e., Depth₆₅₀ = {R₆₃₀ + [3/7 x (R₇₀₀ - R₆₃₀) -R₆₅₀]}/[R₇₀₀- R₄₀₀]), is plotted with depth as a proxy for abundance of chlorins.