A recent review of the literature and available data on latitudinal gradients in marine species richness in OBIS found that in all previous studies, and for a dataset of 65 000 species, they were bimodal, with a dip in richness ...
Costello & Chaudhary (2017) used data from OBIS to show that marine species richness is higher in the coastal tropics and decreases with depth. The paper reviews what factors have led to species diversification, and how this knowledge informs conservation ...