(^) The high diversity of deep-sea sedimentary habitats was surprising, when
discovered, because it exceeds that of shallower, better-studied habitats. Another
extensive sampling and species-identification project, led by Nancy Maciolek,
produced one of the better shallow versus deep comparisons, actually calculated by
Etter and Mullineaux (2001), between the flanks of Georges Bank offshore from New
England, USA (38–167 m) and the deeper continental slope and rise to the southward
(250–2180 m). The comparison is not fully fair, since a greater depth range is
included in the deeper sample set, but the greater diversity in the deeper sediments is
confirmed if only the 1220–1350 m samples are used:
“Synthetic” species numbers vs. sample-area curves (close relatives of rarefaction
curves; Fig. 13.18) confirm the greater diversity of the deeper communities. Both
evenness (the steeper initial slopes) and total species numbers are greater in the deep
sea.
Fig. 13.18 Number of macrofaunal species vs. cumulative sample-area curves based
on a large data-set and calculated by a method similar to that of Fig. 13.16 for shelf
depths on Georges Bank (no symbols) and for the continental slope (various symbols)
to the southeast. Both the initial slopes (equitability) and asymptotes (total species, S)
are greater for the deeper, slope samples.
(^) (Data from Maciolek and others – a US Minerals Management Service project. Figure after Etter & Mullineaux
2001.)
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