Sponges
175
30-50 X 10 3 cells ml- I , starting from the initial values of 1-1. 5 x 10 6 ml- I
(Sorokin, 1978a). The energy expenditures for filtration in sponges was
estimated 1-4 Jlg 0 21- 1 of filtered water. It is remarkable that the sponge
Verongia was not able to cover the energy expended on filtration at the
expense of the food so obtained, when the O2 consumption per 11 of water
filtered was more than 4 Jlg. But this sponge has an additional source of
energy - the photosynthesis of its symbiotic algae and the consumption of
dissolved organic matter.
The respiration rates in sponges range within 0.02-0.07 ml O2 cm -3 of
volume of their colonies per hour, or 0.4-1.5ml02g-lh-1 of dry weight
(Reiswig 1974). The food ration of the sponge community in the fore-reef
zone off Jamaica this author evaluates as being within 1.5-4.0 g of organic
matter m -2 day-I. The food of sponges includes all components of
suspended matter (bacteria, algae, microzooplankton, detritus) and also the
colloidal and dissolved organic matter (Stephens and Schinske 1961; Reiswig
1975; Sorokin 1978b; Vacelet 1979; Wilkinson 1978, 1983b; Wilkinson and
Garrone 1980). Asymbiotic sponges (Mycale) may cover all energy demand
by filter-feeding alone, while sponges which contain symbiotic algae only
about 20% of it. The rest they get by consumption of dissolved organic
matter with the aid of symbiotic heterotrophic bacteria and by using the
photosynthetic products translocated by their algal symbionts. Just this
symbiosis with algae and bacteria helps most sponges to inhabit the upperand middle-depth zones of the reef and to compete successfully with other
sessile fauna.
Sponges have inside their cells symbiotic blue-green algae (cyanobacteria),
and also heterotrophic bacteria. The presence of bacteria inside the cells of
sponges was discovered in 1930. The bacteria were supposed to be parasites
of the sponges, but later it was proved that they are their real symbionts
(Levi and Levi 1965; Vacelet 1971; Wilkinson 1978, 1983b; Wilkinson and
Garrone 1980). These bacteria live inside the special cells of a sponge - the
bacteriocytes, as well as in the mesoglea. The total number of symbiotic
bacteria in sponges attains 10 7 cells g-I of their wet weight. In some sponges
the microbial biomass comprises up to 30-40% of the total cellular biomass
of the host (Vacelet and Donadey 1977; Wilkinson 1978, 1983b). One
sponge usually harbors several (up to seven) different species of bacteria.
Some of these symbiotic bacteria are similar to the ordinary planktonic
bacteria of surrounding waters, but several species were found in sponges
collected in different geographical areas and their appeared to be specific
symbiotic species (Wilkinson et al. 1981). In the mesoglea of the sponge
Terpios filamentous symbiotic bacteria have been found which had blue
pigment. By their morphology those bacteria were similar to cyanobacteria
but they contained no chlorophyll (Santavy 1985).
The function of bacterial symbionts in sponges relates mainly to the
utilization of dissolved organic matter from water that pass through the
hosts body via the channels. Using it, the bacteria build up their biomass,
175
30-50 X 10 3 cells ml- I , starting from the initial values of 1-1. 5 x 10 6 ml- I
(Sorokin, 1978a). The energy expenditures for filtration in sponges was
estimated 1-4 Jlg 0 21- 1 of filtered water. It is remarkable that the sponge
Verongia was not able to cover the energy expended on filtration at the
expense of the food so obtained, when the O2 consumption per 11 of water
filtered was more than 4 Jlg. But this sponge has an additional source of
energy - the photosynthesis of its symbiotic algae and the consumption of
dissolved organic matter.
The respiration rates in sponges range within 0.02-0.07 ml O2 cm -3 of
volume of their colonies per hour, or 0.4-1.5ml02g-lh-1 of dry weight
(Reiswig 1974). The food ration of the sponge community in the fore-reef
zone off Jamaica this author evaluates as being within 1.5-4.0 g of organic
matter m -2 day-I. The food of sponges includes all components of
suspended matter (bacteria, algae, microzooplankton, detritus) and also the
colloidal and dissolved organic matter (Stephens and Schinske 1961; Reiswig
1975; Sorokin 1978b; Vacelet 1979; Wilkinson 1978, 1983b; Wilkinson and
Garrone 1980). Asymbiotic sponges (Mycale) may cover all energy demand
by filter-feeding alone, while sponges which contain symbiotic algae only
about 20% of it. The rest they get by consumption of dissolved organic
matter with the aid of symbiotic heterotrophic bacteria and by using the
photosynthetic products translocated by their algal symbionts. Just this
symbiosis with algae and bacteria helps most sponges to inhabit the upperand middle-depth zones of the reef and to compete successfully with other
sessile fauna.
Sponges have inside their cells symbiotic blue-green algae (cyanobacteria),
and also heterotrophic bacteria. The presence of bacteria inside the cells of
sponges was discovered in 1930. The bacteria were supposed to be parasites
of the sponges, but later it was proved that they are their real symbionts
(Levi and Levi 1965; Vacelet 1971; Wilkinson 1978, 1983b; Wilkinson and
Garrone 1980). These bacteria live inside the special cells of a sponge - the
bacteriocytes, as well as in the mesoglea. The total number of symbiotic
bacteria in sponges attains 10 7 cells g-I of their wet weight. In some sponges
the microbial biomass comprises up to 30-40% of the total cellular biomass
of the host (Vacelet and Donadey 1977; Wilkinson 1978, 1983b). One
sponge usually harbors several (up to seven) different species of bacteria.
Some of these symbiotic bacteria are similar to the ordinary planktonic
bacteria of surrounding waters, but several species were found in sponges
collected in different geographical areas and their appeared to be specific
symbiotic species (Wilkinson et al. 1981). In the mesoglea of the sponge
Terpios filamentous symbiotic bacteria have been found which had blue
pigment. By their morphology those bacteria were similar to cyanobacteria
but they contained no chlorophyll (Santavy 1985).
The function of bacterial symbionts in sponges relates mainly to the
utilization of dissolved organic matter from water that pass through the
hosts body via the channels. Using it, the bacteria build up their biomass,