Biological Oceanography

(ff) #1

The ordering, shown for dominant species, is from the narrowest shallow range,
through the most inclusive range, to the most exclusively deep range. Many of the
species are seen from this to be generalists; they cover at least the upper 1500 m.


(^) Seven of the 39 species in the figure are found throughout the depth range of the
sampling. There are no sharp breaks in the pattern; that is, there are no zones in which
both large numbers of forms have their lower boundary and large numbers of other
forms have their upper boundary. While the fauna changes down slope, there is no
sharp habitat break defined by polychaetes that is associated with just depth.
(^) Next Bilyard plotted the number of species found at each station (Fig. 14.4). He had
found more species to the east – opposite to the absolute abundance pattern. That may

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