Figure 5: (a) Relative carbon absorbance per pixel from integrated NEXAFS particle-average spectrum for a calcareous phytoplankton fragments. (b) Alkane absorbance compared with carbonate absorbance for pixel-by-pixel fit of NEXAFS spectra of all calcareous phytoplankton type particles. Markers are colored by the correlation coefficient for each least-squares linear regression (one color per particle). (c) EDX spectrum of the same particle at 10 keV accelerating voltage. Vertical red lines mark the C, N, O, Si, and Ca absorbances from left to right. N and Si absorbances are from the sample substrate.