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International Journal of Marine Science 2013, Vol.3, No.4, 23-32
http://ijms.sophiapublisher.com
24
Figure 1 The cross-section profile of Jiang Bo Reef.
Note: 1: Inner reef slope; 2a and 2b: inner and outer reef flat; 3: reef crest (reef front); 4a: outer reef slope; 4b: base of reef
slope; 5: slope platform (fore reef)
invertebrate skeletons. The depth gradually decreased
by 1.5~2.0 m from the 40th to the 100th meter of the
transect. Massive and sporadic encrusting colonies of
scleractinian occurred. Colonies of
Heliopora
occurred most often,
Pachyseris, Mycedium
,
Pavona,
Montipora, Podobacia, Goniopora, Alveopora,
Lobophyllum, Pectinia
, and
Euphyllia
were rather
common,
Galaxea, Herpolitha, Fungia, Polyphyllia
,
and large colonies
Porites
were sometimes recorded,
and
Acropora
and small of branching
Porites
occurred
sporadically. The coral covering of the substrate was
7–10%. The associated macrofauna presented by
singular individuals of the bivalve mollusks
Atrina
vexillum
and
Malleus malleus
and of the sea stars
Linckia laevigata
and
Culcita novaeguineae.
The
latter two species also recorded in the same numbers
in all other zones of the reef. At the distance of
100–160 m from the beginning of the transect, the
percentage of coral covering of substrate
pronouncedly increased, from 10 up to 72%, with the
same thing occurring to the size of colonies and
species diversity of scleractinian
Acropora
most of all.
The buttress system began from the 160th meter of the
transect (Figure 2). The species diversity of the corals
sharply increased (by 1.5 times) concurrently with the
variety of their growth forms. The coral covering of
substrate increased to 100%. Young settlements of
scleractinian rather often occurred on an old lamellar
colony of
Acropora
of a 10
0
×60 cm area (Table 1).
This zone extended almost to 70 m. The following
approximately 40 m of the transect were a zone of
Acropora
, in which monospecies settlements of
A.
cytherea
,
A. hyacinthus
,
A. formosa,
and
Porites rus
with individual colonies of
Goniastrea, Astreopora,
Pocillopora, Montipora, Heliopora
, and massive
forms of
Porites
, were clearly distinguished.
Figure 2 Structure of corals settlements at buttress system on
the reef Jiang Bo (depth 12 m)
Table 1 Settlements of small coral on dead lamellar
Acropora
Corals
Number colonies
Acropora
21
Pocillopora
4
Stylophora
3
Goniastrea
3
Favites
2
Fungia
1
Common
34
At a depth of 3~5 m, at the 240th~250th meter of
transect, the reef flat zone extending by 200~300 m
began with individual channels. It characterized by a
continuous covering of substrate by corals (Figure 3)
and interrupted by hollows oriented from northeast to
southwest. The ample tangled settlements, up to
100~150 m wide, were composed of
A. cytherea
,
A.
hyacinthus
,
A. formosa
,
P. rus
,
Montipora aequitu-
berculata
, the seaweed
Chnoospora implexa
and sea
mat
Zoanthus
sp. Individual colonies of scleractinian
and small bioherms spread in channels of sand
sediments. The holothurian
Holothuria atra
(0.2 ind./m
2
),