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the sample transmission spectra, Is> and the blank spectra, Ib, enables the determination of the
absorption efficiency factor for the particle:
Partitioning of the parlicuiate absorption spectra
In order to link individual optical properties to bulk optical properties,a procedure was
developed (Iturriaga and Siegel, 1989). The particulate absorption spectrum (ap (A» can be
calculated from the optical and geometric properties of the particulate assemblage with:
Nt
ap(A)-L Ni-Gi·Qa;C'-)
i-A
where Nt is the number of different particle types, Ni is the number of a specific type, Gj is
the cross-sectional area for the i th type, and Qai(A) is its absorption efficiency factor.
A simpler way to partition the particulate absorption spectra is proposed. We assume that
there are only two types of particles in the ocean: phytoplankton cells and detrital matter.
Thus, the particulate absorption can be partitioned into phytoplankton and detrital components.
ap(A)-aph(A)+adet(A)
or
We use linear regression to decompose the total particulate absorption spectra ap (A), spectra
using the mean Q a.ph (A) and Q a.det (A) spectra for each depth.
=aph(J...)+adet(A)
The quality of fit is evaluated by comparing reconstructed ap (A) to the measured ap (A)
(Fig. 3).