Marine nematode deep-sea biodiversity – hyperdiverse or hype?
Nematodes have been identified as a potentially hyperdiverse group and the deep sea as a potentially hyperdiverse environment (i.e. > 1 million species). A large-scale data set from the equatorial central Pacific is used to estimate regional diversity with results that challenge this view; regional diversity is higher in some coastal waters despite lower sample diversity in coastal waters than in the deep sea. The data suggests a paradigm where the deep sea has modest regional diversity, despite high local diversity through patch dynamics, because similar patches in a similar habitat are repeated for considerable distances. Disturbance in shallow water dominates over patch-dynamic mechanisms reducing local diversity but regional diversity is high because of the close packing of multiple habitats within a single region.
The Pacific data are also used to demonstrate the pitfalls of extrapolating from local to global diversity. There is no reason to conclude that nematodes are less diverse than other benthic groups, indeed where direct comparison is possible the Nematoda appear to be as diverse as the Polychaeta, the most diverse macrofaunal taxon. This analysis is not consistent with the hypothesis that either marine nematodes or the deep-sea benthos are hyperdiverse raising the question whether any environment or metazoan taxon has more than a million species.
Document Type: Guest Editorial
Affiliations: 1: Nematode Group, Department of Zoology, The Natural History Museum, London, UK., Email: firstname.lastname@example.org 2: UMR-CNRS BOME Pavillon Chevreul, Département Milieux et Peuplements Marins, Muséum National d'Histoire Naturelle, 57 rue Cuvier, 75231 Paris Cedex 05, France.
Publication date: 2003-04-01