PARTICULATE ORGANIC MATTER I N SEA WATER
59
stock of particles, partial removal of the stock should lead to further
formation, as it did in the ca.se of continuous harvesting in bubbling
experiments. However, bacterial aggregation is a slower process than
adsorption on bubbles, so that a relatively slow rate of harvesting
would be necessary in order to test this point.
A bottle of freshly filtered inshore water was inoculated with 5 ml
of unfiltered water. The bottle was wrapped with dark cloth to eliminate any possibility of autotrophic growth. Water was pumped from
the bottle at a rate of 0-6 ml/minute via silicone tubing to a glass fibre
filter and thence was returned to the bottle.
Every four days a filter was harvested and replaced by a fresh one.
During this period the calculated flow through the filter was 3.45
litres. The total volume in the experiment was 4.3 litres, so that the
rate of harvesting was 20% of the total volume in a day. I n calculating
results the measured amount of organic carbon on the filter could then
be used to determine the total amount harvested and also the mean
concentration in the bottle during each four-day period. Table I V
shows the mean concentrations and the total yield, the latter obtained
by summing successive four-day yields.
TABLE IV. ORGANIC CARBON CONCENTRATION AND TOTAL YIELD IN
MG C/LITRE UNDER CONDITIONS OF CONTINUOUS, SLOW HARVESTING
T i m e in
M e a n
Total
Days
Concentration
Yield
0-4
4-8
8-12
12-16
16-20
20-24
28-32
36-40
24-28
32-36
0.31
0.12
0.12
0.13
0.10
0.14
0.11
0.08
0.09
0.09
0.25
0.34
0.44
0.55
0.63
0.75
0.83
0.89
0.96
1.03
The mean concentration during the first four days was indicative of
an initial burst of bacterial growth. Subsequently there was a more or
less uniform concentration until the end of the fourth week and a slight
decline thereafter. The concentrations were only slightly smaller and
probably were not significantly different from the value of 0.15 f 0.08
mg C/litre reported in Table I1 (p. 5 5 ) for steady state situations in
59
stock of particles, partial removal of the stock should lead to further
formation, as it did in the ca.se of continuous harvesting in bubbling
experiments. However, bacterial aggregation is a slower process than
adsorption on bubbles, so that a relatively slow rate of harvesting
would be necessary in order to test this point.
A bottle of freshly filtered inshore water was inoculated with 5 ml
of unfiltered water. The bottle was wrapped with dark cloth to eliminate any possibility of autotrophic growth. Water was pumped from
the bottle at a rate of 0-6 ml/minute via silicone tubing to a glass fibre
filter and thence was returned to the bottle.
Every four days a filter was harvested and replaced by a fresh one.
During this period the calculated flow through the filter was 3.45
litres. The total volume in the experiment was 4.3 litres, so that the
rate of harvesting was 20% of the total volume in a day. I n calculating
results the measured amount of organic carbon on the filter could then
be used to determine the total amount harvested and also the mean
concentration in the bottle during each four-day period. Table I V
shows the mean concentrations and the total yield, the latter obtained
by summing successive four-day yields.
TABLE IV. ORGANIC CARBON CONCENTRATION AND TOTAL YIELD IN
MG C/LITRE UNDER CONDITIONS OF CONTINUOUS, SLOW HARVESTING
T i m e in
M e a n
Total
Days
Concentration
Yield
0-4
4-8
8-12
12-16
16-20
20-24
28-32
36-40
24-28
32-36
0.31
0.12
0.12
0.13
0.10
0.14
0.11
0.08
0.09
0.09
0.25
0.34
0.44
0.55
0.63
0.75
0.83
0.89
0.96
1.03
The mean concentration during the first four days was indicative of
an initial burst of bacterial growth. Subsequently there was a more or
less uniform concentration until the end of the fourth week and a slight
decline thereafter. The concentrations were only slightly smaller and
probably were not significantly different from the value of 0.15 f 0.08
mg C/litre reported in Table I1 (p. 5 5 ) for steady state situations in