PARTICULATE ORGANIC MATTER I N SEA W.4TER
91
problem of heterotrophy will first be reviewed, and then the problem
of the general balance between production and consumption will be
reconsidered.
(a) Heterotrophy. Until recently most estimates of the numbers of
bacteria in deep ocean waters were based on plate counts, which greatly
underestimate the total population. Sorokin (1964) examined some
stations in the central Pacific by direct counting methods, and at a
depth of 2 000 m his numbers ranged from 0.8 to 1.03 x l o 6 bacteria
per litre. Other investigators have obtained more or less similar results.
Water samples from the deep ocean commonly contain a few algae.
Most oceanographers have supposed that they represent merely a
remnant that has sunk into deep water and is doomed to quick death.
However, Wood (1956) demonstrated viability of diatoms taken from
ocean depths. More recently Fournier (1 966) and Hamilton et al. (1968)
have found that large concentrations of small cells (2-4 p ) of somewhat
uncertain systematic position are regular inhabitants of ocean deeps.
Bernard (1967) reported large numbers of coccolithophores in Mediterranean waters, but Fournier ( 1 968) has cast serious doubt on the validity
of these observations.
An earlier section mentioned a paper by Holm-Hansen and Booth
(1966) who developed a method for assessing relative quantities of
living and non-living organic matter by means of ATP analyses. They
listed data for fractional partition of this kind at a station located
approximately at 33"N, 119"W. Cellular organic carbon at depths of
10 and 30 m was respectively 33.6 and 95 pgllitre, constituting 42 and
79%, respectively, of total particulate carbon. At 103 m corresponding
figures were 4.6 pg C/litre and 14%. With minor exceptions deep water
samples fell within fairly narrow limits and averaged 1.7 pg C/litre and
3.7% of total carbon.
Hamilton and Holm-Hansen (1967) extended the examination of
the ATP content of marine bacteria, and Hamilton et al. (1968) published additional data from several stations in tropical and subtropical
waters of the Pacific Ocean. There were clear indications of a middepth maximum in ATP and a decrease in deep water. The amount of
carbon in living organisms, as indicated by the usual ATP conversion
factor, was of the order of 1-2% of total particulate carbon in waters
below 1000 m. These authors apparently believed that the small
coloured cells were quantitatively more important than bacteria.
They also mentioned the fact that small green cells from deep water
collections had been established in autotrophic culture, but they stated
that " the nature of the coloured spheres seen on the membrane filters
91
problem of heterotrophy will first be reviewed, and then the problem
of the general balance between production and consumption will be
reconsidered.
(a) Heterotrophy. Until recently most estimates of the numbers of
bacteria in deep ocean waters were based on plate counts, which greatly
underestimate the total population. Sorokin (1964) examined some
stations in the central Pacific by direct counting methods, and at a
depth of 2 000 m his numbers ranged from 0.8 to 1.03 x l o 6 bacteria
per litre. Other investigators have obtained more or less similar results.
Water samples from the deep ocean commonly contain a few algae.
Most oceanographers have supposed that they represent merely a
remnant that has sunk into deep water and is doomed to quick death.
However, Wood (1956) demonstrated viability of diatoms taken from
ocean depths. More recently Fournier (1 966) and Hamilton et al. (1968)
have found that large concentrations of small cells (2-4 p ) of somewhat
uncertain systematic position are regular inhabitants of ocean deeps.
Bernard (1967) reported large numbers of coccolithophores in Mediterranean waters, but Fournier ( 1 968) has cast serious doubt on the validity
of these observations.
An earlier section mentioned a paper by Holm-Hansen and Booth
(1966) who developed a method for assessing relative quantities of
living and non-living organic matter by means of ATP analyses. They
listed data for fractional partition of this kind at a station located
approximately at 33"N, 119"W. Cellular organic carbon at depths of
10 and 30 m was respectively 33.6 and 95 pgllitre, constituting 42 and
79%, respectively, of total particulate carbon. At 103 m corresponding
figures were 4.6 pg C/litre and 14%. With minor exceptions deep water
samples fell within fairly narrow limits and averaged 1.7 pg C/litre and
3.7% of total carbon.
Hamilton and Holm-Hansen (1967) extended the examination of
the ATP content of marine bacteria, and Hamilton et al. (1968) published additional data from several stations in tropical and subtropical
waters of the Pacific Ocean. There were clear indications of a middepth maximum in ATP and a decrease in deep water. The amount of
carbon in living organisms, as indicated by the usual ATP conversion
factor, was of the order of 1-2% of total particulate carbon in waters
below 1000 m. These authors apparently believed that the small
coloured cells were quantitatively more important than bacteria.
They also mentioned the fact that small green cells from deep water
collections had been established in autotrophic culture, but they stated
that " the nature of the coloured spheres seen on the membrane filters