Diversity and endemism in cold waters of the South Atlantic: contrasting patterns in the plankton and the benthos
In total, ca. 7000 zooplanktonic species have been described for the World Ocean. This figure represents less than 4% of the total number of known marine organisms. Of the 7000 zooplanktonic species world-wide, some 60% are present in the South Atlantic; about one third of the latter have been recor...
| Published in: | Scientia Marina |
|---|---|
| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Consejo Superior de Investigaciones Científicas
2005
|
| Subjects: | |
| Online Access: | https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/308 https://doi.org/10.3989/scimar.2005.69s217 |
| Summary: | In total, ca. 7000 zooplanktonic species have been described for the World Ocean. This figure represents less than 4% of the total number of known marine organisms. Of the 7000 zooplanktonic species world-wide, some 60% are present in the South Atlantic; about one third of the latter have been recorded in its Subantarctic waters, and ca. 20% south of the Polar Front. When compared with those of benthic animals, these figures indicate that proportions of the overall inventories that are present in the cold waters are almost two times higher among the zooplankton. In agreement with this pattern, the proportions of Antarctic endemics in the benthos are very significantly higher than those in the plankton. For the water-column dwelling animals, the Polar Front boundary is more important than the Tropical-Subtropical limit, but almost equivalent to the Subtropical-Transitional limit, and weaker in biogeographic terms than the Transitional-Subantarctic boundary. Some of the implications of these dissimilarities, both for ecological theory and for resource allocation strategies, are discussed. Para el Océano Mundial se ha descrito un total de 7000 especies de zooplancton. Esta cifra representa menos del 4% de los organismos marinos conocidos. De las 7000 especies zooplanctónicas del mundo, cerca del 60% está presente en el Atlántico Sur. De este 60%, alrededor de un tercio fueron registradas en aguas subantárticas, y ca. 20% al sur del Frente Polar. La comparación de estos valores con los de los animales bentónicos indica que, con respecto al total de especies descritas, en el zooplancton la proporción que habita las aguas frías duplica a las del bentos. En concordancia con ello, la proporción de endemismos es mucho más alta en el bentos que en el plancton. Para los animales que habitan la columna de agua la barrera del Frente Polar es más importante que el Límite Tropical-Subtropical, pero casi igual que el Límite Subtropical-Transición, y menos importante en términos biogeográficos que el Límite Transición-Subantártico. Se discuten algunas implicaciones de estas diferencias en términos de teoría ecológica y de las estrategias de distribución de los recursos. |
|---|