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1.1. Meiofaunal abundance
Some examples of nematode abundance are given in table 1. The
results for the Indian Ocean are probably unusual because these data are
from a food-rich region. In general, copepods may be expected to be
considerably less abundant than nematodes; the nematode/copepod ratio
varies from 2:1 to 100 percent nematodes 3 .
Biotope
North Atlantic abyssal plain 0.3
Central Pacific abyssal plain 0.1
West European bathyal slope 0.6
Indian Ocean bathyal slope 0.9
Indian Ocean continental rise 0.5
Abundance
Table 1
Examples of nematode abundance, as millions per m 2 , from a variety
of deep-sea sites. 4
1.2. Taxonomy
Around 4000 species of marine nematodes have been described,
mostly from coastal waters, and especially the coastal waters of
northwestern Europe. Few deep-sea nematode species have ever been
described and named. Tietjen 5 investigated the nematodes of the
Venezuela Basin and found that only 1% was known to science. The
nematode species of the Clarion-Clipperton Fracture Zone (CCFZ) and the
Central Indian Basin will almost certainly be largely unknown to science.
Some 358 nematodes from the CCFZ were examined as part of a
provisional taxonomic study by Duane Hope of the Smithsonian Institution,
and 216 of them were sorted into putative morphological species and
identified down to the generic level 6 . This collection is at the Smithsonian
and is a valuable resource for further work in this region.
Bussau 7 made a taxonomic study of the nematodes of the Peru-
Beckens region as part of the Disturbance Recolonization (DISCOL) project.
The animals were sorted into morphological species and drawn but not
published. The collection probably still exists in Kiel, Germany, and may be
useful for further work in the CCFZ. Brown 8 carried out a taxonomic and
ecological analysis of the nematodes of the Central Equatorial Pacific; the
results have just been published 9 . The ecological data and collections from
this study are available in the National Collection of the Natural History
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