Model Studies and Energy Budget in Reef Ecosystems
385
impacts. This method has been supposed to be helpful for developing
practical recommendations for the optimal management of their resources
(Polovina 1984).
The first of such schemes was construed by Odum and Odum (1955) for
one of the reefs at the Enivetok atoll. In their classical work the authors
distributed the bottom communities into separate trophic groups. Then they
created a pyramid of their biomass as follows: plant primary producers -
herbivores - carnivores, in a relation of 703: 132: 11. Their analysis of reef
trophodynamics at this level resulted in developing several, still important,
concepts. Among them there could be mentioned the conclusions about the
definite similarity of reef systems to the ecosystems of the tropical rain
forests in their maturity, the variability of sources of primary production
(microphytobenthos, periphyton, macrophytes, seagrasses, corals and
symbiotic foraminifera) and the complexity of their food webs. Laters other
schemes appeared, revealing the relative functional roles of separate
components or communities in energy and matter flows within the reef
ecosystems, and between them and the pelagic systems of the surrounding
ocean. In our scheme, the central role of microbial populations in the
energy interconnection between separate reef communites has been pointed
out (Sorokin 1973c). In other schemes (Michel et al. 1972; Geptner 1979),
the role of the reef system as a biofilter was demonstrated, and with it the
close relationships between the ecosystems of reef and the surrounding
ocean were established at the level of energy and nutrients exchange.
The first attempt at a model study of coral reef ecosystems has been made
by a special team of 40 specialists (Dahl et al. 1974). This group intended to
divide its biota into several blocks - communities - which were to represent
the trophical levels. Then the participants in this project set about to
describe in their model the trophical links inside these blocks and between
them, as well as the relationships between the blocks and environmental
factors. They intended then to describe the functional role of each block and
to evaluate the energy flows between them. The model so constructed was
supposed to be used to locate the factors which control productivity and the
metabolic processes, and thus to get a key for the monitoring and
management of complex and vulnerable reef systems. But, as work
progressed, this desirable and precious goal was honestly recognized as
unattainable. The reef ecosystem appeared to be too sophisticated for such
brave endeavors and manipulations. The number of the above-mentioned
"blocks" alone was found to be as many as 104. They were unittfd within a
system by over 10 4 various interconnections and over 2 x 10 3 separate
trophic links. Therefore, this model was never realized.
Later, ignoring this userful and instructive experience, the following
attempt at such a model study was made within the ECOPA TH project of
the University of Hawaii at one of the Hawaiian atolls: the French Frigate
shoals atoll (Polovina 1984; Atkinson and Grigg 1984; Grigg et al. 1984).
This is a large crescent reef with a shallow lagoon, and 700 km 2 of the total
385
impacts. This method has been supposed to be helpful for developing
practical recommendations for the optimal management of their resources
(Polovina 1984).
The first of such schemes was construed by Odum and Odum (1955) for
one of the reefs at the Enivetok atoll. In their classical work the authors
distributed the bottom communities into separate trophic groups. Then they
created a pyramid of their biomass as follows: plant primary producers -
herbivores - carnivores, in a relation of 703: 132: 11. Their analysis of reef
trophodynamics at this level resulted in developing several, still important,
concepts. Among them there could be mentioned the conclusions about the
definite similarity of reef systems to the ecosystems of the tropical rain
forests in their maturity, the variability of sources of primary production
(microphytobenthos, periphyton, macrophytes, seagrasses, corals and
symbiotic foraminifera) and the complexity of their food webs. Laters other
schemes appeared, revealing the relative functional roles of separate
components or communities in energy and matter flows within the reef
ecosystems, and between them and the pelagic systems of the surrounding
ocean. In our scheme, the central role of microbial populations in the
energy interconnection between separate reef communites has been pointed
out (Sorokin 1973c). In other schemes (Michel et al. 1972; Geptner 1979),
the role of the reef system as a biofilter was demonstrated, and with it the
close relationships between the ecosystems of reef and the surrounding
ocean were established at the level of energy and nutrients exchange.
The first attempt at a model study of coral reef ecosystems has been made
by a special team of 40 specialists (Dahl et al. 1974). This group intended to
divide its biota into several blocks - communities - which were to represent
the trophical levels. Then the participants in this project set about to
describe in their model the trophical links inside these blocks and between
them, as well as the relationships between the blocks and environmental
factors. They intended then to describe the functional role of each block and
to evaluate the energy flows between them. The model so constructed was
supposed to be used to locate the factors which control productivity and the
metabolic processes, and thus to get a key for the monitoring and
management of complex and vulnerable reef systems. But, as work
progressed, this desirable and precious goal was honestly recognized as
unattainable. The reef ecosystem appeared to be too sophisticated for such
brave endeavors and manipulations. The number of the above-mentioned
"blocks" alone was found to be as many as 104. They were unittfd within a
system by over 10 4 various interconnections and over 2 x 10 3 separate
trophic links. Therefore, this model was never realized.
Later, ignoring this userful and instructive experience, the following
attempt at such a model study was made within the ECOPA TH project of
the University of Hawaii at one of the Hawaiian atolls: the French Frigate
shoals atoll (Polovina 1984; Atkinson and Grigg 1984; Grigg et al. 1984).
This is a large crescent reef with a shallow lagoon, and 700 km 2 of the total