45
800
WH-8103
600
'00
200
' "
a
(,)
a
450
500
550
600
C
2000
' "
(,)
WH-7803
' "
1500
~
0
::l
U.
1000
' "
>
.- 500
- co
-
' "
a:
,so
500
5SO
600
500
Sargasso Sea Synechococcus sp.
'00
300
200
100
'50
SOO
sso
600
WAVELENGTH
Figure 4. Fluorescence excitation spectra (uncorrected) of individual Synechococcus from cultured cells and
natural cell types. Emission measured at 575 nm (uncorrected spectra) indicates natural strains in the
Sargasso Sea contain high ratios of phycourobilin to phycoerythrobilin.
In addition, the abundance of phytoplankton and detrital particles (N ph and N del) may be
estimated using regression coefficients (A and B) and the relationship between Q. and ap.
ap(A)-Nph 'Gph'Q aph(A) + N det -Gdet'Q adet(A)
Thus,
and