The Role of Food Patches in Maintaining High Deep-Sea Diversity: Field Experiments With Hydrodynamically Unbiased Colonization Trays

To test whether deep-sea macrofaunal diversity is enhanced by specialization on small-scale food patches, we deployed colonization trays by submersible at 900-m depth for 23 d. Trays were buried flush with the seafloor to minimize potential hydrodynamic bias. Treatments included prefrozen, natural sediment that was unenriched or enriched with either Thalassiosira sp. or Sargassum sp. Density comparisons and rarefaction analysis indicate that Thalassiosira sp. attracted high densities of several taxa of juvenile oppotunists, and Sargassum sp. trays were colonized by fewer individuals of a more diverse fauna. Ambient faunal diversity was higher and densities lower than enrichment treatments, although unenriched trays did not attain ambient densities. results suggest that juveniles, rather than adults, specialize on specific patch types, thus contributing to high deep-sea diversity; this bottleneck may be fundamentally different from less diverse, shallow-water macrofaunal assemblages.