Читать книгу Tropical Marine Ecology - Daniel M. Alongi - Страница 49

Marine realms (Figure 5.4a) and ecoregions (Figure 5.4b) have been identified across the marine biome representing what is an ecological characterisation based on water temperature, depth, and substrate rather than historical distributions based on long‐term climatic patterns (Figure 5.4). Some history, however, is preserved in some benthic taxa with limited dispersal ability and some show a latitudinal pattern in species diversity and composition. These latitudinal patterns still appear to represent modern differences rather than historical ones, thus the boundaries between regions have shifted latitudinally with changing ocean temperature during the Pleistocene, and the composition of local assemblages has changed as species’ ranges have expanded or contracted (Spalding et al. 2007).

In the Tropical Atlantic Realm, there are six ecoregions: Tropical NW Atlantic, North Brazil Shelf, Tropical SW Atlantic, St. Helena and Ascension Islands, the West African Transition, and the Gulf of Guinea. The Western Indo‐Pacific Realm consists of seven ecoregions: Red Sea and Gulf of Aden, Somali/Arabian, Western Indian Ocean, West and South India Shelf, Central Indian Ocean Islands, Bay of Bengal, and the Andaman Sea. The Central Indo‐Pacific Realm has several tropical ecoregions: South China Sea, The Sunda Shelf, Java Transitional, Tropical NW Pacific, Western Coral Triangle, Eastern Coral Triangle, Sahul Shelf, NE Australian Shelf, NW Australian Shelf, and the Tropical SW Pacific. The Eastern Indo‐Pacific Realm consists of six island ecoregions: Hawaii, Marshall, Gilbert and Ellis Islands, Central Polynesia, Cook Islands, and Southeast Polynesia, Marquesas and Easter Island. The Tropical East Pacific Realm consists of both the Tropical East Pacific and Galapagos ecoregions.

There is a level of provincialism that does reflect the influence of tectonic and oceanographic history on the distribution and origin of lineages. Tropical oceans have been a barrier to the distribution of cold‐water organisms, but there has also obviously been some level of distinction among tropical provinces, at least for some taxa. For instance, there has been a historical subdivision between some Pacific and Indian Ocean species of sea horses (Hippocampus; Lourie et al. 2005) and the mantis shrimp (Haptosquilla pulchella; Barber et al. 2000). Thus, there are true biogeographic divisions across the tropical marine biome that may not necessarily reflect history but certainly reflect current or recent environmental cues and are separated by zones of rapidly changing species composition.