Catalogus

Annelids, bivalves, crustaceans, echinoderms, sponges, and sea anemones produce most marine bioturbation. These organisms respond in predictable ways to major physical and chemical stressors in their environment. Such stressors include sediment texture, substrate consistency, sedimentation rate, subaerial exposure, temperature, turbidity, oxygenation, and water salinity. Invertebrates prefer to burrow in sand and firm mud, and generally avoid water saturated mud and coarse-grained sediment. Loosegrounds and softgrounds display the most diverse trace assemblages, compared to stiff, firm, and hard substrates. Low sedimentation rates result in high bioturbation intensity and diverse trace assemblages. Increasing sedimentation rate decreases the intensity of bioturbation. Subaerial exposure shifts faunal populations towards trophic generalists who produce simple structures. Highly turbid water causes deposit-feeding behaviors to predominate. Water salinity controls endobenthos and their burrowing assemblages. Normal marine conditions have diverse ichnofauna, whereas brackish water settings display low diversity but sometimes high-density bioturbation. Hypersaline waters contain low diversity ichnofaunas. Low dissolved oxygen manifests in low abundances, diversities, and densities of trace assemblages. With increasing latitude, burrowing organisms shift to deeper water, burrowing by crustaceans decreases, polychaete-generated structures are more abundant, and the size of burrows increases. Despite the current knowledge base of invertebrate neoichnology in siliciclastic shallow marine environments, the link between physico-chemical environmental stressors and burrowing remain mostly qualitative.