Paleobenthos

Paleobenthos refers to the fossil record of organisms that lived on, in, or immediately above the bottom substrates of ancient aquatic environments, including oceans, seas, lakes, and rivers. The term encompasses a broad range of life forms, from sessile suspension feeders to burrowers and detritivores, and relies on both body fossils and trace fossils that record benthic activity.

The composition of paleobenthos includes groups such as bivalves, brachiopods, gastropods, echinoderms, crustaceans, polychaetes, ostracodes, foraminifera, and microbialites, as well as trace fossils like burrows, borings, and feeding marks. Studying these organisms helps reconstruct the nature of the substrate, energy regime, oxygen levels, and water depth in ancient ecosystems, and it informs patterns of diversity, biogeography, and ecological change through time.

Preservation of paleobenthos is strongly influenced by sedimentary context. Fine-grained deposits and Lagerstätten can preserve delicate structures and soft tissues, while more typical fossil assemblages are biased toward hard-shell or hard-part organisms. Taphonomic processes, post-depositional alteration, and sampling intensity can affect apparent diversity and abundance, requiring careful interpretation and, when possible, multiple lines of evidence.

Applications of paleobenthos include reconstructing past environments and climate, correlating stratigraphic sequences, and testing hypotheses about sea-level changes and basin evolution. As a component of paleoecology, it provides insight into how benthic communities responded to disturbances such as global warming events, anoxia, and mass extinctions, contributing to a broader understanding of Earth's historical ecology.