 Amazon
The Amazon forest surpasses the
limits of the borders of countries, occupying the
Orinoco and Amazonas basins, moving forward from
its tributaries and penetrating to the north in
the countries of Guyana, Suriname and French
Guiana. It reaches the Atlantic, going by the
delta of Amazonas, covering again part of the
northeast of Maranhão state with a
characteristic vegetation that will be described
below. Accompanying the rivers, Amazon invades
the area of the plateau, and therefore of
savannah; to the west it finds the Andes in the
countries of Bolivia, Peru, Ecuador and Colombia.
 Its great vastness
reaches Central America (with forest that has
characteristics different from that of the
Brazilian Amazon) and it can be found even in the
south of Mexico, according to Luiz Emygdio de
Mello Filho. Adding all areas covered by the
forest, we have the incredible number of 6
million square kilometers. The Brazilian part is
calculated at 3 million and one half square
kilometers. This represents more than 50% of the
forest and 42% of Brazilian territory. According
to Aziz Ab´Saber, the Amazon has surprising
characteristics that turn maintainable its green
vastness. Aziz focuses attention on the
extraordinary continuity of the forests, and of
the greatness of its pluvial net. In spite of its
vastness the Amazon presents little variety of
ecosystems, considering analyses of different
areas and altitudes. Aziz highlights the monotony
found in the Amazon lands, always with discharges
and dense forests, well served of rivers and
wildlife.
The geographical position of the
Amazon (in the area of the equator) has resulted
in a concentration of solar energy,
accompanied by an almost permanent provisioning
of humid air masses, with absence of cold or dry
stations, and without a very large thermal width.
These according to Ab´Saber are the
characteristics that have facilitated the
appearance of the great green mass. In the
periphery forest area, in the Brazillian states
from Rondônia to Acre exists the "coldness
phenomenon" that consists of a penetration
of the Atlantic air tropical mass in Amazon in
the winter period of the Southern
Hemisphere. This causes a small temperature
drop.
 Generally, the
Amazon receives immense water precipitation of
from 1600 to 3600mm a year. excepting the fields
of Boa Vista, in Roraima State. The medium
temperature oscillates between 24 and 27°C.
Amazon fauna and flora colors and
contrast never fail to impress. There exists a
contrast of colors even in the rivers. The white
rivers transport a great amount of fine
sediments, as clay in solution, at the same time
that sand is moved. The black rivers are born
among firm lands and run there, with many forests
that pass their margins. Little amount of
sediments is taken by the water, just organic
matter in decomposition are found there,
consisting in their largest part of the leaves'
layer and animal remains of the forest ground.
Despite the fact that they carry few sediments
mixed in their waters, they transport some sand.
At times this causes the formation of banks of
sand, in their course. Rivers of green water also
exist, like the low Tapajós River. The rivers of
green water almos t always come from a
long distance, mainly between the savannah and
the beginning of the forest areas. Harald Siolo
makes detailed hydro biochemical studies about
several amazon rivers, and one of his conclusions
is that the "white" rivers have larger
amount of fish and their flat land are more
fertile, because they contain larger amount of
sediments.
The igarapé (igara means
embarkation dug in the one tree log, pé means
way) in scientific terms means amazon courses of
water of first or second order. These are
primary tributaries of small, medium and big
rivers, and their courses are an access to the
forests. The igarapés is used even today as
roads for the local inhabitants. A typical
igarapé runs gently into an almost closed forest
tunnel, with palm trees aligned on its margins,
between small ravines and the immense forest.
Most of the igarapés have dark waters because
they run inside the forest; their waters have
organic matter in suspension.
 Igapó is the part
of the flooded forest or a swamp covered with
vegetation. The igapós are formed by river and
igarapés inundations that are stagnant for some
time. This water flows by "furos"
(natural connections between rivers and lakes),
that are the same as " corixos " of the
Pantanal area.
With all these characteristics, the
Amazon shelters an enormous variety of animals
and vegetable species that until the current day
were not studied.
We have knowledge that all life of
this immense ecosystem rotates around water.
Little areas are not directly affected by
inundations, and these are called firm forests or
of firm earth. In these forests we find the
highest trees, some with more than 50 meters
tall.
 In the swamp
forests, trees with board shape roots are found,
because these allow the plant to have better
attachment to the soil. In these forests are
found such interesting adaptations as seeds that
float to germinate in other places, far away from
the mother plant. The trees of these forests, are
capable to be submerged for many months.
The Amazon is a complex ecosystem
that gathers an invaluable wealth of fauna and
flora. It can be used to bring unimaginable
benefits to man. But the immensity hides the
fragility of this living mass.
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[ ECOSYSTEM ]
[ Amazon ] [ Caatinga ] [ Savannah ] [ Atlantic Forest] [
Augustifolia
Forest ] [ Pampas ] [ Pantanal ]
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