Marine species richness

SCIENTIFIC CORRESPONDENCE but show that the Norwegian and Greenland seas are relatively impoverished (as expected), that there are more species in mid-latitudes in both hemispheres , and that tropical slopes may be richer in SIR - Estimates for the number of species than temperate ones. The mespecies in the deep seal have been dis- dian £(S100) of all data in the figure, cussed in News and Views 2 • Grassle and Arctic species excluded, is 22 species. These new data bring into question Maciolek1 reported on 14 samples taken within 176 km from the slope (depth the appropriateness of using data from range 1,500-2,500 m) of the north- one site in the North Atlantic for global western Atlantic where they found 798 estimates. New calculations of isopod species of invertebrates among 90,677 richness from samples taken during the individuals in 21 m2 of box-core samples. Gay Head-Bermuda transect 4 are conUsing rarefaction methods and estimates sistently higher than Grassle and of species change along spatial gradients Maciolek's figure from the same region but are on average lower than those for a similar 8O..--------------------~ latitudinal range off southeastern Australia (manu60 script submitted). The N oceans of the Southern k k 40 • e 9 eee ••• Hemisphere are much larI· ger than those of the 20 Northern Hemisphere and the North Atlantic is relatively young compared 0 •••••••• •• • ; •• ••••• • •• • •• • ••. •••••••••••••••••.•••. •• •• . • ~•• •~i.~•.~ . . •.. . . ... . . to the Pacific. Therefore, b b b d dd extrapolations to the glo20 bal species number should b fIlb include data from the CC C A A A A