50 
PACIFIC SCIENCE, VoL XX, January 1966 
The similarity of the two regression coeffi- 
cients for AB-36-H, and likewise for AB-8-H, 
suggest a coefficient near 1.0 for the regression 
of M on H. Such values (1.025 for AB-36-H, 
1.128 for AB-8-H) are obtained when points 
are grouped for Bartlett’s method on the basis of 
C values. If points are grouped on the basis of H 
values the corresponding coefficients are 0.701 
and 1.091. 
DISCUSSION 
Recognition of Possible Steady-state Situations 
A steady state among standing crops of phyto- 
plankton, herbivores, and primary carnivores 
could be defined as a state in which material 
added to each trophic level (by photosynthesis, 
or by feeding on the level below) is continu- 
ously balanced by material lost from it (some 
assimilated by the level above, and some lost by 
other kinds of death, respiration, sinking, and 
active or passive emigration). 
Measurements of the three standing crops in 
a number of different situations could be con- 
sidered consistent with the steady-state hypo- 
thesis if: (i) all total correlation coefficients 
were positive and significant, (ii) the partial 
correlation coefficient of phytoplankton and 
herbivores was positive and significant, and ( iii ) 
the other two partial correlation coefficients 
were nonsignificant. In explanation of (iii), a 
significant positive partial correlation between 
phytoplankton and carnivores, independent of 
herbivores, would not be biologically realistic 
under the steady-state hypothesis; and a similar 
coefficient between herbivores and carnivores, 
independent of phytoplankton, could signify 
some geographical redistribution of biota at the 
higher trophic levels (e.g., carnivores moving 
from herbivore-poor to herbivore-rich areas), 
and probable violation of the hypothesis. 
Table 3 shows that conditions (i), (ii), and 
(iii) are fulfilled only for the AB-ll-Z set of 
observations, considering all zooplankton as 
herbivores. Conditions (i) and (iii) are ful- 
filled and condition (ii) is almost fulfilled for 
the AB-8-H set in which copepods only were 
considered as herbivores; in this case the partial 
correlation coefficient of phytoplankton and 
herbivores is positive and nearly significant with 
only 5 degrees of freedom. 
The group of 1 1 or 8 station-pairs represents 
a statistical, objective selection of a smaller set 
of pairs from a larger set. The data of the larger 
set of pairs satisfied conditions ( i ) and ( ii ) but 
not (iii), and it was thought that the data of 
the smaller set might satisfy all three conditions. 
If a steady state exists, the standing crop of 
chlorophyll a might be expected to be positively 
correlated with primary productivity (produc- 
tion rate) in the same water column. This cannot 
be shown for the smaller group of station-pairs 
because productivity was estimated at only 6 of 
the 1 1 noon stations, and the incubation method 
and depth of sampled column were not the same 
for all 6. It can be shown for the 19 noon 
stations of Table 1, A, for which comparable 
water-column (0-100 m) productivity data are 
available (see Table 4, unpublished data from 
R. W. Holmes ) . The measurements were made 
by the C14 method using a constant-illumination 
"laboratory” incubator (Blackburn et al., 1962); 
TABLE 4 
Productivity (Primary Production Rate) for Water Column 0-100 m at Noon Stations Listed 
in Table 1, A* 
STN. 
PROD. 
STN. 
PROD. 
STN. 
PROD. 
STN. 
PROD. 
6 
5.2 
32 
5.0 
62 
31.0 
86 
3.2 
8 
7.1 
34 
9.5 
72 
8.0 
100 
14.8 
13 
3.2 
49 
28.3 
74 
5.0 
122 
23.4 
15 
1.8 
56 
11.0 
76 
74.0 
139 ** 
15.0 
23 
11.5 
58 
11.8 
79 
10.8 
* In mgC/m 2 /hr. ; obtained by the C 14 method, samples incubated at 1,000 foot-candles; unpublished values from R. W. 
Holmes, based on sample data listed by Blackburn et ah, 1962, Appendix I. 
** Productivity data for this station were listed for station 137 in Blackburn et al., 1962, Appendix I. 
