Bacterio Plankton
89
low rations in sponges and in ascidians were mostly the consequence of a
high content of inert skeletal organic carbon in their bodies, which was
taken into account during the calculations of relative rations.
As regards optimum concentrations of bacterioplankton for the feeding of
filtering benthic and planktonic animals, corresponding values estimated
with the use of labeled bacterioplankton are given in (Fig. 3.7). For most
fine filterers, like sponges and Oicopleura, this was attained with a
bacterioplankton biomass of 18-30 mg C m -3 which represented an average
level in most reef waters. For crude reef filterers, which used only the
aggregated part, the optimum was 3-4 times more: 60-80mgCm- 3 , while
ordinary biomass in water over the reefs reached 30 to 100 mg C m -3. Thus
not only fine- but crude-filterers too can acquire their food rations or a
significant part of it by feeding only on the bacterioplankton.
The corals themselves can actively feed on bacterioplankton (Table 3.8;
Fig. 3.7). Their relative rations with feeding on bacterioplankton attain up
to 5%, i.e., the same values as of powerful filtering animals, such as the
sponges or oysters. More detailed data are given in the chapter on feeding
of corals (cf. Sect. 9.2.1).
The assimilability of ingested bacterioplankton by filter-feeders appeared
to be very high: 60-80% (Table 3.8).
A scheme generalizing the results of studies on the trophic importance of
bacterioplankton in reef ecosystems is given in Fig. 10.7. It shows that
bacteria accomplish an important function, being an intermediary energy
link between the bottom autotrophs and benthic secondary producers, the
filtering animals. Quantitative evaluations of this function of
bacterioplankton are given elsewhere (d. Sect. 10.3).
3.1.3 Luminescent Bacteria
Luminescent bacteria, which inhabit oceanic waters, emit light without
external stimulation at the expense of energy of their metabolism resulting
in the accumulation of A TP in them. The latter participates in light
emittance via the luciferin-luciferase system of luminescent bacteria
(Tchumakova and Gitelson 1975; Primakova 1985). They are represented in
the sea by the rod-shaped cells and are related to the group of
enterobacteria - inhabitans of animal intestines. Their habitat main is indeed
the intestines of marine animals and their special luminescent organs. Being
excreted by animals with feces, they enter the bacterioplankton, and being
ingested again by filter-feeders, can get into the intestines again, thus
distributing themselves among the populations of marine animals. The
luminescent bacteria appeared to be very abundant in coral-reef habitats. In
waters above the reef their numbers are more than by an order over those in
oceanic waters, comprising 10 3 _10 4 cells ml- 1 according to counts of their
colonies on nutrient broth agar medium. Sometimes they attained there
89
low rations in sponges and in ascidians were mostly the consequence of a
high content of inert skeletal organic carbon in their bodies, which was
taken into account during the calculations of relative rations.
As regards optimum concentrations of bacterioplankton for the feeding of
filtering benthic and planktonic animals, corresponding values estimated
with the use of labeled bacterioplankton are given in (Fig. 3.7). For most
fine filterers, like sponges and Oicopleura, this was attained with a
bacterioplankton biomass of 18-30 mg C m -3 which represented an average
level in most reef waters. For crude reef filterers, which used only the
aggregated part, the optimum was 3-4 times more: 60-80mgCm- 3 , while
ordinary biomass in water over the reefs reached 30 to 100 mg C m -3. Thus
not only fine- but crude-filterers too can acquire their food rations or a
significant part of it by feeding only on the bacterioplankton.
The corals themselves can actively feed on bacterioplankton (Table 3.8;
Fig. 3.7). Their relative rations with feeding on bacterioplankton attain up
to 5%, i.e., the same values as of powerful filtering animals, such as the
sponges or oysters. More detailed data are given in the chapter on feeding
of corals (cf. Sect. 9.2.1).
The assimilability of ingested bacterioplankton by filter-feeders appeared
to be very high: 60-80% (Table 3.8).
A scheme generalizing the results of studies on the trophic importance of
bacterioplankton in reef ecosystems is given in Fig. 10.7. It shows that
bacteria accomplish an important function, being an intermediary energy
link between the bottom autotrophs and benthic secondary producers, the
filtering animals. Quantitative evaluations of this function of
bacterioplankton are given elsewhere (d. Sect. 10.3).
3.1.3 Luminescent Bacteria
Luminescent bacteria, which inhabit oceanic waters, emit light without
external stimulation at the expense of energy of their metabolism resulting
in the accumulation of A TP in them. The latter participates in light
emittance via the luciferin-luciferase system of luminescent bacteria
(Tchumakova and Gitelson 1975; Primakova 1985). They are represented in
the sea by the rod-shaped cells and are related to the group of
enterobacteria - inhabitans of animal intestines. Their habitat main is indeed
the intestines of marine animals and their special luminescent organs. Being
excreted by animals with feces, they enter the bacterioplankton, and being
ingested again by filter-feeders, can get into the intestines again, thus
distributing themselves among the populations of marine animals. The
luminescent bacteria appeared to be very abundant in coral-reef habitats. In
waters above the reef their numbers are more than by an order over those in
oceanic waters, comprising 10 3 _10 4 cells ml- 1 according to counts of their
colonies on nutrient broth agar medium. Sometimes they attained there