Australian Geographic — May-June 2017

May. June 33

nature watch

ORGAN PIPE

CORAL

Tubipora musica

Size: Up to 1m across

Most soft corals have

limestone spicules that

provide some structural

support by slightly

stiffening the soft tissues.

In organ pipe coral, the

spicules fuse to create a

hard skeleton of pipe-like

tubes, with each single

polyp bearing eight

feathery tentacles.

Colonies of organ pipe

coral can occupy large

patches of reef. Inhabits

shallow waters down to

about 12m.

SMOOTH

CAULIFLOWER

CORAL

Stylophora pistillata

Size: Up to 30cm across

Common in shallow reef

areas, particularly those

that are exposed to strong

wave action, although it

can occur to a depth of

about 15m. It is a hard,

branching coral with blunt,

slightly flattened ends.

Colour ranges from cream,

pink or blue to greens.

HUMP CORAL

Porites densa

Size: Up to 15cm across

Common in shallow inner

reefs, but also found less

frequently on the outer

reef. This small, stony coral

grows in a rounded hump

shape. It prefers to grow

in the absence of other

species, although it can

occasionally be found near

algae or other corals. It

uses symbiotic algae to

photosynthesise by day

and filter feeds on plankton

by night.

COMMON

MUSHROOM

CORAL

Fungia fungites

Size: Up to 28cm across

Unlike most corals, does

not form colonies.

Mushroom corals are large,

free-living, solitary polyps

that aren’t attached to the

substrate. They are flat or

dome-shaped with wide,

slit-like mouths. Young

mushroom corals begin

life on stalks and bear a

striking resemblance to

actual mushrooms. Found

in shallow areas on the reef

crest and flat, but mostly

within cavities on the

reef flat.

FLOWERPOT

CORAL

Alveopora sp.

Size: Polyps can grow up to

10cm long and 2cm wide

Flowerpot corals are made

up of many individual

polyps joined together at

the base of their skeletons

to form branches, columns

or dome-shaped colonies.

The individual polyps are

highly flexible and active,

and constantly moving

around and feeding. Their

colonies can spread widely,

growing many metres

across. Found in upper reef

slopes with low wave

action, 5–25m deep.

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