Table 1. - Estimated numbers of marine zooplnaktonic species for the World Oceanand for the South Atlantic

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.

迄今全球海洋已被描述的浮游动物（zooplankton）物种总计约7000种，该数量仅占已知海洋生物总物种数的4%不到。在全球7000种浮游动物中，约60%分布于南大西洋海域；其中约三分之一的物种在该海域的亚南极（Subantarctic）水域有记录，另有约20%的物种分布于极锋（Polar Front）以南海域。相较于底栖动物（benthic animals）的相关统计数据，上述结果表明：冷水水域中浮游动物的物种占总物种库的比例几乎是底栖动物的两倍。这一分布格局与南极特有种在底栖生物（benthos）群落中的占比显著高于浮游生物（plankton）群落的现象相符。对于水层栖居动物而言，极锋（Polar Front）界线的生物地理分区意义比热带-亚热带（Tropical-Subtropical）分界更为显著，但与亚热带-过渡带（Subtropical-Transitional）界线的分区价值近乎相当；而就生物地理学维度而言，其重要性弱于过渡带-亚南极（Transitional-Subantarctic）界线。本文还探讨了这些分布差异在生态学理论与资源分配策略两方面的部分启示。