GLOBAL-SCALE LATITUDINAL PATTERNS OF SPECIES-DIVERSITY IN THE DEEP-SEA BENTHOS

LATITUDINAL gradients of species diversity are ubiquitous features of terrestrial and coastal marine biotas, and they have inspired the deve lopment of theoretical ecology1-3. Since the discovery of high species diversity in the deep-sea benthos4, much has been learned about local 5,6 and regional7-9 patterns of diversity. Variation in diversity on l arger scales remains poorly described. Latitudinal gradients of divers ity were unexpected because it was assumed that the environmental grad ients that cause large-scale patterns in surface environments could no t affect communities living at great depths10. Here we report that dee p-sea bivalves, gastropods and isopods show clear latitudinal diversit y gradients in the North Atlantic, and strong interregional variation in the South Atlantic. Many seemingly incompatible mechanisms have bee n proposed to explain deep-sea species diversity11. The existence of r egular global patterns suggests that these mechanisms operate at diffe rent spatial and temporal scales.