91
of the lagoon biota as a set of dynamic,
interlocking cycles
rather than as a food web of the type depicted by Hiatt and
Strasburg
(1960).
Figure 7 presents the cycling of life ina
coral atoll lagoon from such a viewpoint.
trophic levels are considered:
In this model,
three
(1) primary producers--the
autotrophic plankton and benthic autotrophs,
(2)
primary con-
sumers--heterotrophic plankton and benthic herbivorous fish,
and (3) secondary consumers--pelagic and benthic carnivores.
The cycles are tied together through the detritus produced by
the excretion and death of their members.
"omnivore" has been included,
Although the term
the terms "herbivore"
"carnivore" have been used in the broadest sense,
and
in full
recognition of the facultative nature of the feeding behavior
of many of the organisms so classified.
Inspection of Figure 7 shows that,
the pelagic division,
consumers).
plankton,
in the fish fauna of
there are no strict herbivores
(primary
Plankton feeders ingest mainly the larger zoo-
but undoubtedly take in autotrophs as well in strain-
ing the plankton from sea water.
Particulate radiomaterials
suspended in the pelagic division would be taken up initially
by the biota by adsorption to both autotrophic and heterotrophic
plankton or direct ingestion by the latter.
Sither way they
become available to all the trophic levels of pelagic fish.