Metre-scale vertical zonation of corals and sponges on a deep-marine cliff reflects trophic resource partitioning.

Corals and sponges are considered foundational species and can create biodiversity hotspots in the deep sea, yet little is known of their competitive interactions, particularly with respect to resource partitioning among benthic fauna. Here we report on the feeding ecology of deep-water corals, sponges, ascidians, and anemones from a ~ 450 m deep submarine canyon wall off Nova Scotia, Canada. Analysis of bulk stable isotopes of carbon and nitrogen confirms isotopic niche partitioning between species despite their physical proximity.

Implications of selective predation on the macroevolution of eukaryotes: evidence from Arctic Canada.

Existing paleontological data indicate marked eukaryote diversification in the Neoproterozoic, ca. 800 Ma, driven by predation pressure and various other biotic and abiotic factors. Although the eukaryotic record remains less diverse before that time, molecular clock estimates and earliest crown-group affiliated microfossils suggest that the diversification may have originated during the Mesoproterozoic.