The Coolidge examiner., 1937-10-07
Sea Gardens of the Tropics Are
Replete With Lovely Growths

While reef-forming corals and
gorgonians are confined to tropical
waters and to comparatively shall
low seas, not exceeding 20 to Is
fathoms in depth, other species,
which are solitary in habit, or that
form small colonies, grow in deep
seas, and in a few instances in
more northern shallow waters.
The beautiful astrangia is found
along the New England coast, en-
crusting rocks where the tide flows
freely. in patches about the size of
ones hand. Its delicate rosy tints
remind one Of the terrestrial arbu-
tus. Again. those first cousins of
the corals, the sea anemones, adorn
tide pools and wharf piles with their
colorful beauty along the entire
Atlantic and Pacific coasts. while in
the Tropics their brilliant hueS add
to the glories of the coral reefs
themselves.
These lowly creatures, together
associated with them, have filed a
most important place in determin-
ing the geographical and geological
features of the globe. Their mas
sive reefs penetrate the surface of
the tropic seas and must be re-
corded carefully on photographic
charts for the safety of navigators.
Vast Effects of Tiny Creatures.
Their islands dot the southern
oceans. many of them the abode Of
men. Their huge submarine depos-
its, elevated by geologic changes of
past ages, have been important fac
tors in determining the outline and
surface features of continents and
have entered into the structure of
mountain ranges. They have fur
nished building stones for houses
and marble for statuary.
Their disintegrated substance has
fertilized fields and grown crops, f.
nally washing down to the seas, to
be worked over again by the
Ubiquitous polyps for future ages.
Many diverse species of coral
composing a reef form structures,
ever growing higher and higher,
crowding and becoming entangled
with each other in thickets of gro
tesque and weird beauty. The soft
colors of their outer surface run
through varied hues of rose, pink,
orange, tan, yellow, green, blue and
purple-all the colors of the spec
trum. These colors are partly due
to pigments in the living tissues,
which invest the surface of the coral
limestone skeleton, and partly to
another very interesting phenome-
non.
Microscopic marine plants, or al
gae, live in the inner tissues of the
translucent polyp wall. Each indi-
vidual is disk-shaped single cell.
amber yellow in color. They null
tiply by millions, often completely
filling the cells of the endodermalI
layer.
Since they are plants they use the
carbon dioxide excreted by the
polyp in which they live, and in the
presence of sunlight transform it in
to food for themselves, giving forth
oxygen in the process. The latter
gas, so essential for animal exist
ence, is utilized in turn by the polyp
in its vital processes. Hence there
is maintained partnership between
the plant and the animal of equal
importance to both.
Gets Strong Colors From Algae.
If the coral colony happens to be
located in strong sunlight, the algae
multiply with great rapidity, giving
the polyp's tissues deep golden
hue. This fact accounts for the rich
tans and saffrons of the great elk
horn corals that form the extensive
treelike growths in the Andres is
land reef.
If the coral is growing in a SUBJ
marine nook where the sunlight is
weak, the algae are relatively few
and the coral tissues are seen in
their original pigmented color. For
example, the brain coral is natural
ly green, due to the color of it's
pigment, and that is the way it ap-
pears in deeper waters and shaded
localities; but in moderately illu-
minated areas the microscopic plant
partners are more numerous along
the SUBMITS of the sinuous ridges of
the coral, producing yellow color
in contrast with the green in the
winding valleys between them. FL
nally, brain corals located in the
brilliant sunshine of the shadows
on the top of the reef are so COM
pletely impregnated with algae as
to appear a deep chocolate brown