108
E. D. 9. CORNER AND ANTHONY 0. DAVIES
suggested that regeneration of nitrogen might be the explanation of the
continued growth, the rcmineralized form being used up very quickly
so that inorganic nitrogen concentrations did not become detectable.
Ketchuni et nl. (1958) thought that this remineralization occurred at
depth, the nitrogen then being returned t o the euphotic zone by eddy
diffusion. The possibility that the presence of ammonium-nitrogen
might account for thc continued plant production was examined by
Vaccaro (1963) for the waters off the New England coast. I n August
1962, although only trace levels of nitrite and nitrate-nitrogen were
present in the euphotic zone, nitrogen : phosphorus ratios between 1 : 1
and 7 : 1 resulted when ammonium-nitrogen concentrations were also
taken into account. However, the AN: AP value calculated from the
total inorganic nitrogen concentrat,ion was still low at 10.8: 1. Earlier
in the year, the winter AN: AP value was surprisingly high at 20.8:l
and only during the spring outburst in April was the value normal at
15.3:l.
Vaccaro (1963) showed that the atomic ratios N:P in the particulate
matter suspended in the euphotic zone were similar t o the assimilation
ratios:
Particulate N/P
AN/ AP value
atomic ratios
for water column
(0-10 m)
Gulf of Maine, August 10132
11.2
16.6
South of Nova Scotia, April 1962
10.8
15.3
Higher nitrogen : phosphorus ratios were obtained for the particulate
matter gathered from deeper waters: these were thought t o be due t o a
more rapid loss of phosphorus than of nitrogen during the remineralization of the organic detritus.
The small seasonal variation of the particulate nitrogen : phosphorus
ratio discovered by Vaccaro is similar t o that found previously by
Harris and Riley ( 1956) for phytoplankton collected over the period of
a year from Long Island Sound. Here, the nitrogen : phosphorus ratios
only varied between 20: 1 in February t o a little over 13: 1 in midsummer
(See Table I). During the same period the nitrogen : phosphorus ratio
(excluding ammonium-nitrogen) in the sea water had decreased from
about 8: 1 at the winter maximum t o approximately zero after the spring
bloom (Riley and Conover, 1956). Harris and Riley’s average ratio of
16*2:1 was in good agreement with the value of 16:l originally proposed
by Fleming (1940) and which is now usually regarded as representing
the average nitrogen : phosphorus ratio in marine plankton (Redfield
et al., 1963). Direct experimental support for this ratio has been pro-
E. D. 9. CORNER AND ANTHONY 0. DAVIES
suggested that regeneration of nitrogen might be the explanation of the
continued growth, the rcmineralized form being used up very quickly
so that inorganic nitrogen concentrations did not become detectable.
Ketchuni et nl. (1958) thought that this remineralization occurred at
depth, the nitrogen then being returned t o the euphotic zone by eddy
diffusion. The possibility that the presence of ammonium-nitrogen
might account for thc continued plant production was examined by
Vaccaro (1963) for the waters off the New England coast. I n August
1962, although only trace levels of nitrite and nitrate-nitrogen were
present in the euphotic zone, nitrogen : phosphorus ratios between 1 : 1
and 7 : 1 resulted when ammonium-nitrogen concentrations were also
taken into account. However, the AN: AP value calculated from the
total inorganic nitrogen concentrat,ion was still low at 10.8: 1. Earlier
in the year, the winter AN: AP value was surprisingly high at 20.8:l
and only during the spring outburst in April was the value normal at
15.3:l.
Vaccaro (1963) showed that the atomic ratios N:P in the particulate
matter suspended in the euphotic zone were similar t o the assimilation
ratios:
Particulate N/P
AN/ AP value
atomic ratios
for water column
(0-10 m)
Gulf of Maine, August 10132
11.2
16.6
South of Nova Scotia, April 1962
10.8
15.3
Higher nitrogen : phosphorus ratios were obtained for the particulate
matter gathered from deeper waters: these were thought t o be due t o a
more rapid loss of phosphorus than of nitrogen during the remineralization of the organic detritus.
The small seasonal variation of the particulate nitrogen : phosphorus
ratio discovered by Vaccaro is similar t o that found previously by
Harris and Riley ( 1956) for phytoplankton collected over the period of
a year from Long Island Sound. Here, the nitrogen : phosphorus ratios
only varied between 20: 1 in February t o a little over 13: 1 in midsummer
(See Table I). During the same period the nitrogen : phosphorus ratio
(excluding ammonium-nitrogen) in the sea water had decreased from
about 8: 1 at the winter maximum t o approximately zero after the spring
bloom (Riley and Conover, 1956). Harris and Riley’s average ratio of
16*2:1 was in good agreement with the value of 16:l originally proposed
by Fleming (1940) and which is now usually regarded as representing
the average nitrogen : phosphorus ratio in marine plankton (Redfield
et al., 1963). Direct experimental support for this ratio has been pro-