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Geographical
situation
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On
the two-dimensional geographical map: the coral Tuamotu
archipelago, which is situated in the middle of the Pacific
Ocean, is one of 5 French Polynesian archipelagos. The others
are the Les Gambier archipelago, the Austral Islands, the
Society Islands and the Marquesas Islands. Far
from the continents, the Tuamotu are a group of low
islands stretching from the north-west to the south-east, 300
to 1600 km from Papeete. In
comparison with European countries, these islands occupy a
surprisingly large area, if one includes the lagoons and the
surrounding sea, although the emergent lands amount to only a
small proportion of the archipelago as a whole.
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On
the three-dimensional geographical map: beneath the
archipelago, there is a large underlying shelf with irregular
topographical features, lying at depths of 1000 to 3000m.
However, most of the atolls are based on a volcanic mass 300
to 500 km wide and 1500 km long lying at depths of 1500 to
2000m, which is surrounded on the edges by ocean beds 4000 to
5000m deep.
Physical
characteristics
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In 1842, Darwin put forward the
opinion that the atolls
resulted from a series of evolutive changes, as shown on
the graph below. This theory was supported one century
later by the plate tectonics processes observed as well as
by the findings made on drilling sites in the Marshall
Islands and the Eastern Tuamotu atolls.
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The
atoll lagoons are surrounded by chains of low islets called "motu", which
are only a few metres above the present sea-level. The atolls vary
greatly in size (from more than 1800 km2 in the case of
Rangiroa to less than 50 km2 in that of Mataiva), and
their lagoons can either communicate with the open sea via widely
open channels or be completely enclosed (click
here for
further information). The landscape is always fairly
similar on the whole, however, since the same levelling effects of
the sea and the same constructive effects of the biological
organisms inhabiting this particular biotope, are to be seen all over the atolls.
The
"motus" are being
constantly eroded away, and will perhaps one day all become
completely submerged. There is little fresh water to be found on
them, the soil is of the primary kind, and the only fertile spaces
are those surrounding the lagoon. In addition, the total surface of the atolls amounts to only 2% of the oceanic
territory area and the emergent land occupies only 0.1% of this area: this indicates how extremely fragile the
terrestrial and marine life is bound to be on these tiny oases
surrounded by a practically desert ocean.
The
fact that the access to these atolls is dangerous, since they are
difficult to sight accurately, as well as being surrounded in may
places by coral reefs, has accentuated their isolation and their
backwardness.
Climate
The
climate on the atolls is hot and humid, although not excessively so.
Most of the islands benefit from the influence of the prevailing
Easterly trade winds, which are usually quite moderate, and the sea
also helps to cool down the temperature on the atolls and prevent
them from becoming
too hot.
There
are two seasons in the Tuamotu archipelago: a wet season from
December to March, and a dry season from July to Otober.
The
mean temperature ranges around 25°C, and the daily temperature
range is approximately 4°C. Population
The
Tuamotu islands have been showing a remarkably fast population
growth rate, even in comparison with the French Polynesian Territory
as a whole. Two possible explanations for this population boom come
to mind: an increase in the birth rate and immigration processes.
The results of the 1996 census help to answer this question: like
the Leeway Islands, the Tuamotu/Gambier islands have been receiving
large streams of immigrants. The development of pearl farming and
tourism and the improvement of the sea and air transport systems
have attracted the inhabitants of other islands to these atolls.
As
far as the birth rate is concerned, although there is a tendency in
French Polynesia for the fertility rate to decrease, this tendency has been compensated for by a decrease in the
mortality rate. These tendencies obviously reflect a change in birth
control practices and the considerable progress achieved in terms of
the treatment of disease. Communications
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Sea
transport, in the form of coastal trade from one island to
another, is still the main means whereby the isolation of
the archipelagos is relieved and their inhabitants supplied
with their requirements.
203 000 tonnes of merchandise were transported
in 1996, 88% of which were distributed among the
archipelagos. |
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Since
1993, there has been a constant increase in the quantities
of goods - especially foodstuffs, building materials and
petroleum products -
transported. This increase has been due partly to the
efforts made to develop modern hotel complexes, and partly
to the flourishing pearl farming industry. |
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The
intensity of the internal air traffic has been increasing
steadily, as far as both freight and passenger transport are
concerned. |
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References
Dupon
JF, Sodter F, 1993, les îles Tuamotu in Atlas de Polynésie Française, ORSTOM
Editions, 11-13 Bonvallot
J, Laboute P, Rougerie F, Vigneron E (1994), Les atolls des
Tuamotu, ORSTOM, 296p. ITSTAT
(1998), Les tableaux de l'économie Polynésienne, Institut
Territorial de la Statistique, 380p.
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Atoll_site_
