a)
50
..--.
~
~ 100
Reconstruction of Surface Ocean Nitrate Utilization
1)13e (%0 VS. PDB)
KJ KJ KJ I KJ ~ ~
~ W I\.) ~ 0 to ())
b)
1)15N (%0 vs. air)
463
Fig. 11. (a) I) 13 Cvalues from GeoB 1008-3 (dashed line) and GeoB 1016-3 (solid line; from Miilleretal. 1994); (b) Bulk
I)"N values from GeoB 1008-3 (dashed line) and GeoB 10 16-3 (solid line) from Holmes et al. (1997).
a)
0.2
Q)
"C
::I
::= 01
c.'
E
23
~
J?
41
~
0.2 0.4 0.6 0.8 1.0
Frequency (1/period)
b) 0.2
Q)
"C
::I
::= 01
c.'
E
41
it
~
0.2 0.4 0.6 0.8 1.0
Frequency (1/period)
Fig. 12. Results of harmonic analyses performed on the 1)1sN signal of (a) GeoB 1008-3 and (b) GeoB 1016-3 using
the software program SPECTRUM (Schulz and Stattegger 1997). A Fischer/Siegel test for compound periodicity
was employed and significant peaks are labeled. The dashed line shows the significance level. The peaks at 100 kyr
were significant in both cores, but due to the shortness of the records, they are not discussed.
50
..--.
~
~ 100
Reconstruction of Surface Ocean Nitrate Utilization
1)13e (%0 VS. PDB)
KJ KJ KJ I KJ ~ ~
~ W I\.) ~ 0 to ())
b)
1)15N (%0 vs. air)
463
Fig. 11. (a) I) 13 Cvalues from GeoB 1008-3 (dashed line) and GeoB 1016-3 (solid line; from Miilleretal. 1994); (b) Bulk
I)"N values from GeoB 1008-3 (dashed line) and GeoB 10 16-3 (solid line) from Holmes et al. (1997).
a)
0.2
Q)
"C
::I
::= 01
c.'
E
23
~
J?
41
~
0.2 0.4 0.6 0.8 1.0
Frequency (1/period)
b) 0.2
Q)
"C
::I
::= 01
c.'
E
41
it
~
0.2 0.4 0.6 0.8 1.0
Frequency (1/period)
Fig. 12. Results of harmonic analyses performed on the 1)1sN signal of (a) GeoB 1008-3 and (b) GeoB 1016-3 using
the software program SPECTRUM (Schulz and Stattegger 1997). A Fischer/Siegel test for compound periodicity
was employed and significant peaks are labeled. The dashed line shows the significance level. The peaks at 100 kyr
were significant in both cores, but due to the shortness of the records, they are not discussed.