PLANKTON I N NITROGEN AND PIIOSPIIORUS CYCLES
109
vided by Grill and Richards (1964) who followed the rate of nutrient
regeneration from decomposing phytoplankton which had been cultured
from an inoculum of mixed plant cells obtained from the sea. For much
of the decomposition period, nitrogen (as ammonia) and phosphorus
(as phosphate) were released in the ratio of 16:l.
TABLE I. SEASONAL VARIATION IN NITROGEN AND PHOSPHORUS CONTENTS AND
IN THE N : P RATIO OF PHYTOPLANKTON FROM LONG ISLAND SOUND IN 1963.
(Data from Harris and Riley, 1956)
yo Dry Weight
Date
Nitrogen Phosphorus
-
Jan. 27
2.25
0.33
Feb. 18
2.33
0.26
Mar. 9
2.87
0.36
Mar. 23
2.09
0-27
June 1
4.77
0.73
July 7(a) 4.15
0-57
July 7(b) 4.43
0.64
Aug. 4
2.73
0.48
Fob. 1
2.24
0.32
Average
3.10
0.44
N : P
(Atoms)
15-1 :1
19.8:l
17.6:l
17.1 :1
14.4:l
16*2:1
1!5.5:1
12*6:1
15.5:l
16*2:1
Main species present (aa percenfqe
of total cell count)
_-____
__.
A, 72.1 ; B, 8.1 ; D, 9.6
A, 82.7 ; D, 8.2
A, 96.0
A, 72.2 ; C, 8.7 ; E, 8.9
F, 26.0; H, 8.7; Q, 43.8; It, 6.1
F, 14-3; M, 34.5; Q, 32.1 ; R, 10.8
J, 8.6 ; K, 5.9 ; L, 64.0 ; N, 8.7
G, 6.0; L, 18.0: P, 53.3
-
Code
A
B
C
D
E
P
G
H
J
K
L
M
N
P
Q
R
Skeletonenaa costatum (Grcvillc) Clovo
Thahsweira decipiens (Van Hciirck) Jorgonsoii
T . nordenakioldii Clcvo
Thalassionema nitzschioides Hustcdt
Lauderia borealis Gran
Nitzclchia closterium (Ehrcnbcrg) Wm. Smith
N . pungena var. dlantica Clcvo
Asterionella j a p o n k Gran
Chaetoceros afine Lauder
C . curvisetum Clcve
C . decipiena Clcvc
Coscinodiscw centralis var. paci&u Gran & Angst
Prormntrum scutellum B. Schroder
Peridinium trochoideum (Stcin) Lcmm.
Gonyaulax africana Schiller
G. cochlea Mew.
B. Apparent oxygen utilization
The concept of " apparent oxygen utilization " (AOU), first introduced by Redfield (1942), is increasingly being used in connection with
the stoichiometry of nutrient changes brought about biologically. It is
109
vided by Grill and Richards (1964) who followed the rate of nutrient
regeneration from decomposing phytoplankton which had been cultured
from an inoculum of mixed plant cells obtained from the sea. For much
of the decomposition period, nitrogen (as ammonia) and phosphorus
(as phosphate) were released in the ratio of 16:l.
TABLE I. SEASONAL VARIATION IN NITROGEN AND PHOSPHORUS CONTENTS AND
IN THE N : P RATIO OF PHYTOPLANKTON FROM LONG ISLAND SOUND IN 1963.
(Data from Harris and Riley, 1956)
yo Dry Weight
Date
Nitrogen Phosphorus
-
Jan. 27
2.25
0.33
Feb. 18
2.33
0.26
Mar. 9
2.87
0.36
Mar. 23
2.09
0-27
June 1
4.77
0.73
July 7(a) 4.15
0-57
July 7(b) 4.43
0.64
Aug. 4
2.73
0.48
Fob. 1
2.24
0.32
Average
3.10
0.44
N : P
(Atoms)
15-1 :1
19.8:l
17.6:l
17.1 :1
14.4:l
16*2:1
1!5.5:1
12*6:1
15.5:l
16*2:1
Main species present (aa percenfqe
of total cell count)
_-____
__.
A, 72.1 ; B, 8.1 ; D, 9.6
A, 82.7 ; D, 8.2
A, 96.0
A, 72.2 ; C, 8.7 ; E, 8.9
F, 26.0; H, 8.7; Q, 43.8; It, 6.1
F, 14-3; M, 34.5; Q, 32.1 ; R, 10.8
J, 8.6 ; K, 5.9 ; L, 64.0 ; N, 8.7
G, 6.0; L, 18.0: P, 53.3
-
Code
A
B
C
D
E
P
G
H
J
K
L
M
N
P
Q
R
Skeletonenaa costatum (Grcvillc) Clovo
Thahsweira decipiens (Van Hciirck) Jorgonsoii
T . nordenakioldii Clcvo
Thalassionema nitzschioides Hustcdt
Lauderia borealis Gran
Nitzclchia closterium (Ehrcnbcrg) Wm. Smith
N . pungena var. dlantica Clcvo
Asterionella j a p o n k Gran
Chaetoceros afine Lauder
C . curvisetum Clcve
C . decipiena Clcvc
Coscinodiscw centralis var. paci&u Gran & Angst
Prormntrum scutellum B. Schroder
Peridinium trochoideum (Stcin) Lcmm.
Gonyaulax africana Schiller
G. cochlea Mew.
B. Apparent oxygen utilization
The concept of " apparent oxygen utilization " (AOU), first introduced by Redfield (1942), is increasingly being used in connection with
the stoichiometry of nutrient changes brought about biologically. It is