117
would expect higher flux rates through filters although the actual
transport rates will, of course, be a function of the concentration
gradient, mixing, and the interaction of solute ions with the
membranes. My ammonium flux rates were based on a 5 ~M difference in
concentration gradient whereas Furnas's phosphate fluxes were based on
an initial gradient of 1000 ~M. Since our flux rates are essentially
equivalent and since there were large differences in the concentration
gradient and the pore area to volume ratio of the two types of cages,
our transport rates may represent maximum values.
If they are maximum values then we can assume that the ammonium
fluxes measured in dialysis tubes are comparable to filters.
Dialysis
tubes should, therefore, support a biomass equivalent to that in a
cage before membrane transport becomes limiting and the population
enters the linear growth phase. Growth rates should be equivalent.
Growth Rates
Comparisons between growth rates in tubes
using natural populations from Tampa Bay, Florida
1982.
Populations were screened through a 153
and cages were made
during the summer of
~mNitex (R) net to
remove larger zooplankton.
Growth rates, estimated from changes in
chlorophyll and cell numbers over a two day incubation period
indicated there was little difference in growth rates using the two
methods with 3 exceptions (Table 2).
In 2 of these 3 exceptions
growth rates in the cages were lower than in tubes and in one pair of
cages where light was reduced by an additional 50%, the growth rate
was higher.
Growth rates of some species from one trial (trial 2) were faster
in tubes than in cages while others, such as Prorocentrum minimum; did
not grow in tubes (Table 3). Similar results were obtained for other
trials.
Initial biomass levels for the three trials were high and ranged
from 13 to 16 ~g Chl 1-1 with final concentrations in the range of 40
a
to 90 ~g Chla 1- 1
Nutrient availability may have limited the final
yield and growth rate in both the tubes and cages.
Since growth in
diffusion cultures is a function of the biomass present and the
nutrient flux rate then reducing the biomass should increase nutrient
availability and yield increased growth. rates if nutrient transport
limited
growth.
Conversely,
growth
rates
in
dialysis
tubes
would expect higher flux rates through filters although the actual
transport rates will, of course, be a function of the concentration
gradient, mixing, and the interaction of solute ions with the
membranes. My ammonium flux rates were based on a 5 ~M difference in
concentration gradient whereas Furnas's phosphate fluxes were based on
an initial gradient of 1000 ~M. Since our flux rates are essentially
equivalent and since there were large differences in the concentration
gradient and the pore area to volume ratio of the two types of cages,
our transport rates may represent maximum values.
If they are maximum values then we can assume that the ammonium
fluxes measured in dialysis tubes are comparable to filters.
Dialysis
tubes should, therefore, support a biomass equivalent to that in a
cage before membrane transport becomes limiting and the population
enters the linear growth phase. Growth rates should be equivalent.
Growth Rates
Comparisons between growth rates in tubes
using natural populations from Tampa Bay, Florida
1982.
Populations were screened through a 153
and cages were made
during the summer of
~mNitex (R) net to
remove larger zooplankton.
Growth rates, estimated from changes in
chlorophyll and cell numbers over a two day incubation period
indicated there was little difference in growth rates using the two
methods with 3 exceptions (Table 2).
In 2 of these 3 exceptions
growth rates in the cages were lower than in tubes and in one pair of
cages where light was reduced by an additional 50%, the growth rate
was higher.
Growth rates of some species from one trial (trial 2) were faster
in tubes than in cages while others, such as Prorocentrum minimum; did
not grow in tubes (Table 3). Similar results were obtained for other
trials.
Initial biomass levels for the three trials were high and ranged
from 13 to 16 ~g Chl 1-1 with final concentrations in the range of 40
a
to 90 ~g Chla 1- 1
Nutrient availability may have limited the final
yield and growth rate in both the tubes and cages.
Since growth in
diffusion cultures is a function of the biomass present and the
nutrient flux rate then reducing the biomass should increase nutrient
availability and yield increased growth. rates if nutrient transport
limited
growth.
Conversely,
growth
rates
in
dialysis
tubes