A Summary of Natural and Human-Induced Variables
in Coastal Marine Ecosystems of Latin America
B. KJERFVE, U. SEELIGER, and L. DRUDE DE LACERDA
1 Climate and Hydrology
Coastal marine ecosystems along the coast of South and Central America
from 56°S to 33°N latitude are largely governed by interactions of broadscale oceanographic conditions with climate and hydrology. In consequence, a comprehensive understanding of variations in structure and processes of these ecosystems requires an overview of climatic, hydrological, and
oceanographic variations as well as an assessment of the modifying
impact of human activities.
In the far south of Latin America the climate is chilly subarctic marine
but is tropical for most of the continent. Rainfall varies greatly between the
extremes at Calama in the Atacama Desert on the northern coast of Chile,
where rain has never been measured, to an annual precipitation of
12,717mm in the upper Atrato Basin in Colombia (Eslava 1992). Freshwater runoff into the Pacific and Atlantic oceans was determined by the
Miocene uplift of the Cordilleras (Andes), which separated the continent
into a narrow, tectonically active Pacific coast and a vast, stable shield with
Precambrian rocks and shallow sedimentary deposits to the east (see chapter by Kellogg and Mohriak). As a result, more than 90% of the continental
drainage flows into the Atlantic Ocean and the Caribbean Sea, including
the drainages of the Amazon (Brazil), Orinoco (Venezuela), and Parana
(Argentina-Brazil-Paraguay-Bolivia), which are among the largest rivers in
the world. Several other very large rivers also drain to the east or north,
such as the Magdalena (Colombia), which empties into the Caribbean, and
the Uruguay (Uruguay), Tocantins (Brazil), and Sao Francisco (Brazil)
rivers which discharge into the Atlantic Ocean (Fig. 1; Table 1). The drainage basins east of the Andes are relatively large but small in numbers,
whereas the Pacific coast is characterized by numerous small river basins.
However, in the high rainfall area of Pacific Colombia the discharges are
Ecological Studies, Vol. 144
U. Seeliger and B. Kjerfve (eds.)
Coastal Marine Ecosystems of Latin America
© Springer-Verlag Berlin Heidelberg 2001
in Coastal Marine Ecosystems of Latin America
B. KJERFVE, U. SEELIGER, and L. DRUDE DE LACERDA
1 Climate and Hydrology
Coastal marine ecosystems along the coast of South and Central America
from 56°S to 33°N latitude are largely governed by interactions of broadscale oceanographic conditions with climate and hydrology. In consequence, a comprehensive understanding of variations in structure and processes of these ecosystems requires an overview of climatic, hydrological, and
oceanographic variations as well as an assessment of the modifying
impact of human activities.
In the far south of Latin America the climate is chilly subarctic marine
but is tropical for most of the continent. Rainfall varies greatly between the
extremes at Calama in the Atacama Desert on the northern coast of Chile,
where rain has never been measured, to an annual precipitation of
12,717mm in the upper Atrato Basin in Colombia (Eslava 1992). Freshwater runoff into the Pacific and Atlantic oceans was determined by the
Miocene uplift of the Cordilleras (Andes), which separated the continent
into a narrow, tectonically active Pacific coast and a vast, stable shield with
Precambrian rocks and shallow sedimentary deposits to the east (see chapter by Kellogg and Mohriak). As a result, more than 90% of the continental
drainage flows into the Atlantic Ocean and the Caribbean Sea, including
the drainages of the Amazon (Brazil), Orinoco (Venezuela), and Parana
(Argentina-Brazil-Paraguay-Bolivia), which are among the largest rivers in
the world. Several other very large rivers also drain to the east or north,
such as the Magdalena (Colombia), which empties into the Caribbean, and
the Uruguay (Uruguay), Tocantins (Brazil), and Sao Francisco (Brazil)
rivers which discharge into the Atlantic Ocean (Fig. 1; Table 1). The drainage basins east of the Andes are relatively large but small in numbers,
whereas the Pacific coast is characterized by numerous small river basins.
However, in the high rainfall area of Pacific Colombia the discharges are
Ecological Studies, Vol. 144
U. Seeliger and B. Kjerfve (eds.)
Coastal Marine Ecosystems of Latin America
© Springer-Verlag Berlin Heidelberg 2001