English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Lambshead et al. (2000) analysed the most coherent deep-sea nematode data available for evidence of biodiversity gradients over latitudinal distances. But, as these authors pointed out, there are considerable problems with extant deep-sea data, including the nematode data, when analysed for this purpose. However, we still feel that ‘new data will only be acquired slowly and are likely to possess many of the inadequacies of the old data for much the same reasons’ so it seems ‘worthwhile to test for latitudinal gradients with the data we have while bearing in mind their problems’ (Lambshead et al. 2000). Nevertheless, analysis of large-scale deep-sea patterns is an important new area of enquiry; we published the data to facilitate reanalysis and discussion and it is encouraging to see such a thoughtful response (Rex et al. 2001, this volume). The main comment in Rex et al. 2001 concerns the omission of depth from the multiple regression of species richness (on sample size and latitude), and they rightly point out that if depth is included, the significance of latitude is lost. Unfortunately, latitude and depth are confounded amongst our station locations with a negative correlation between latitude and depth — higher latitude stations tend to be shallower, partly due to the geography of the North Atlantic. The question is whether depth should be incorporated into the analysis. We will address this by (1) considering what is known about the relationship between nematode diversity and depth, (2) re-analysing the data to test for whether depth or latitude is more powerful as an explanation of the results, and (3) exploring whether the pattern produced by Lambshead et al. (2000) fits within what is known about deep-sea nematode biodiversity. (1) Nematode depth-diversity relationships: The relationship between depth and nematode ecological diversity was analysed by Boucher & Lambshead (1995) using a large, by nematode standards, data-set (that included the data analysed in Lambshead et al. 2000). These authors reported that there was no difference between bathyal and abyssal nematode diversity but that the hadal Puerto Rico Trench samples had significantly lower diversity; so, a case could be made for removing the hadal stations from the analysis. Rex et al. (2001) suggest that a diversity-depth relationship in the nematode data-set over abyssal-bathyal depth ranges might be present but hidden because the nematode data have been collected from a number of locations. Diversity-depth relationships for nematodes at a single location have not been investigated to the same extent as for macrofauna. Such relationships were analysed for nematode and polychaete assemblages in the Rockall Trough (Lambshead et al. 1994, Paterson & Lambshead 1995), although it must be admitted that the nematode data were sparse (3 depth stations only, data given in Lambshead et al. 2000). The polychaetes show a depth-diversity pattern but there is little evidence that nematodes are similarly affected. The explanation for a different response for the 2 taxa may be that the polychaete pattern appears to be a response to water current disturbance. Deepsea polychaetes are sensitive to physical disturbance (e.g. Glover et al. 2001) whereas both shallow water and deep-sea nematodes are robust to such disturbance (Warwick et al. 1990, Lambshead et al. 2001, respectively). A more comprehensive study of nematode depthdiversity relationships at a single location was carried out by Soetaert et al. (1991). This work investigated the diversity at 6 depth stations, but unfortunately only from 160 to 1220 m, in the western Mediterranean. These authors showed no evidence for an association between nematode diversity, or species richness, and depth. The nematode pattern is quite different from

North Atlantic latitudinal diversity patterns in deep-sea marine nematode data: a reply to Rex et al.