366
Nutrition of Corals
formula is the net production of zooxanthellae, T part of P nz translocated to
the polyp and Ma respiration of the animal tissues of the polyp. The values
of P nz were calculated by accepting that the ratio of respiration to biomass in
zooxanthellae is the same as in animal tissues of polyps. The value of Twas
calculated as the ratio (Pnz - G)/Pnz' where G is the production of
zooxanthellae used by them for their own growth. The latter was estimated
by measurements of their generation time when recording the frequency of
occurrence of cells in the state of mitosis in freshly isolated suspension of
zooxanthellae (Wilkerson et al. 1983). The last-mentioned authors estimated
in this way the energy balance in the corals Stylophora pistillata living at
depths of 15 and 45 m in different illuminations (Table 9.2; Fig. 9.8). The
table shows that in the illuminated zone colonies of this coral may complete
their energy debet even from only the autotrophic source, while those living
in poor light less than half, with the P/Mt-ratio in the latter at midday over
1. Thus, these colonies should get the other part of the necessary energy of
over 50% from heterotrophic sources of nutrition. The CZAR values in this
coral were estimated with 93-96% (Fig. 9.8).
The same estimations were cavried out also in the corals Pocillopora
eydoxy (Davies 1984) and Porites (Edmunds and Davise 1986). But in this
case the values of P nz have been calculated using the directly measured
values of zooxanthellae respiration (Mz) in their suspensions in vitro: P nz =
Pt - Mz. The Mz values, as measured in suspensions of zooxanthellae in
vitro, were estimated to be 9-21% of Pb whereas after the calculations
mentioned above only 2-3%. Correspondingly, the obtained CZAR values
were lower: 90% for Pocillopora and 78% for Porites (Table 9.22). The
polyps used for their own respiration about 30% of translocated
photosynthesis production. They were assumed to be using the rest on
Polyps respiration
(67,1)
Growth of
zooxanthellae
(1,4)
Fig. 9.8. Scheme of expenditure of photosynthetic production by zooxanthellae (Pt ,
relative values) in the energy metabolism of the coral Stylophora: M= respiration of
zooxanthellae, and Pnz their net autotrophic production. (After Muscatine 1984)
Nutrition of Corals
formula is the net production of zooxanthellae, T part of P nz translocated to
the polyp and Ma respiration of the animal tissues of the polyp. The values
of P nz were calculated by accepting that the ratio of respiration to biomass in
zooxanthellae is the same as in animal tissues of polyps. The value of Twas
calculated as the ratio (Pnz - G)/Pnz' where G is the production of
zooxanthellae used by them for their own growth. The latter was estimated
by measurements of their generation time when recording the frequency of
occurrence of cells in the state of mitosis in freshly isolated suspension of
zooxanthellae (Wilkerson et al. 1983). The last-mentioned authors estimated
in this way the energy balance in the corals Stylophora pistillata living at
depths of 15 and 45 m in different illuminations (Table 9.2; Fig. 9.8). The
table shows that in the illuminated zone colonies of this coral may complete
their energy debet even from only the autotrophic source, while those living
in poor light less than half, with the P/Mt-ratio in the latter at midday over
1. Thus, these colonies should get the other part of the necessary energy of
over 50% from heterotrophic sources of nutrition. The CZAR values in this
coral were estimated with 93-96% (Fig. 9.8).
The same estimations were cavried out also in the corals Pocillopora
eydoxy (Davies 1984) and Porites (Edmunds and Davise 1986). But in this
case the values of P nz have been calculated using the directly measured
values of zooxanthellae respiration (Mz) in their suspensions in vitro: P nz =
Pt - Mz. The Mz values, as measured in suspensions of zooxanthellae in
vitro, were estimated to be 9-21% of Pb whereas after the calculations
mentioned above only 2-3%. Correspondingly, the obtained CZAR values
were lower: 90% for Pocillopora and 78% for Porites (Table 9.22). The
polyps used for their own respiration about 30% of translocated
photosynthesis production. They were assumed to be using the rest on
Polyps respiration
(67,1)
Growth of
zooxanthellae
(1,4)
Fig. 9.8. Scheme of expenditure of photosynthetic production by zooxanthellae (Pt ,
relative values) in the energy metabolism of the coral Stylophora: M= respiration of
zooxanthellae, and Pnz their net autotrophic production. (After Muscatine 1984)