Benthic Communities Associated with Carbonate Rubble and Adjacent Soft Sediments in a Shallow Coastal Area of O'ahu, Hawai'i

Abstract

Although the shallow, wave-swept sedimentary environment of the near-shore subtidal region of Hawai'i would be expected to be characterized by a relatively homogenous community associated with shifting sediments, small-scale variability in the macrofauna exists. Benthic communities associated with rubble are distinct from nearby sand areas. Higher densities, taxonomic richness, and benthic biomass are characteristic of sediments containing carbonate rubble fragments (ranging from 2 to 64 mm in size). Rubble communities are dominated by annelids and a variety of crustaceans (primarily amphipods, isopods, and tanaids); sand communities are dominated by nematodes. The unconsolidated carbonate rubble community displays an undisturbed Abundance Biomass Comparison (ABC) pattern; the sand community displays a disturbed pattern. The divergent ABC patterns may reflect differences in substrate stability.