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Tiering in the Sea – Reefs and Burrows (Late Palaeozoic)

  1. Rachel A Wood

Published Online: 15 SEP 2010

DOI: 10.1002/9780470015902.a0001668.pub2

eLS

eLS

How to Cite

Wood, R. A. 2010. Tiering in the Sea – Reefs and Burrows (Late Palaeozoic). eLS. .

Author Information

  1. University of Edinburgh, Edinburgh, UK

Publication History

  1. Published Online: 15 SEP 2010

Abstract

Tiering is often considered as a proxy for the ecological complexity of ancient communities. Ancient reefs in the Late Palaeozoic were dominated by microbial communities that formed complex substrate topographies, together with a variety of calcified algae and suspension-feeding metazoans that populated open and cryptic surfaces. Tiering in epifaunal communities increased significantly in the Ordovician to form complex tiered communities that persisted throughout the Palaeozoic. By contrast, infaunal tiering developed slowly, with occupation of deeper depths being achieved only by the Lower Carboniferous.

Post-Permian mass extinction epibenthic and infaunal biotas were of very low diversity, and composed of small-sized, low-tiered suspension-feeding opportunists. Epifaunal communities increased in complexity and tiering after ∼1 million years as crinoids and bryozoans returned. Complexity and depth of burrowing communities only returned to pre-crisis levels by the Middle Triassic.

Key Concepts:

  • Tiering is considered as a proxy for the ecological complexity of ancient communities.

  • Late Palaeozoic reefs and mud mounds bore complex substrate topographies produced in part by microbial carbonate production: these supported diverse and well-tiered open and cryptic communities that persisted to the end of the Permian.

  • Infaunal tiering developed slowly from the Ordovician, with occupation of deeper depths being achieved only by the Lower Carboniferous.

  • Post-Permian mass extinction epibenthic and infaunal biotas consisted of very low diversity, small-sized and low-tiered communities.

  • Epifaunal communities increased in complexity and tiering as crinoids and bryozoans returned. Infaunal communities saw the return of suspension feeders and finally crustaceans, but the size and depth of burrowing communities only returned to pre-crisis levels by the Middle Triassic.

Keywords:

  • history of reefs;
  • diversification of habitats;
  • burrowing depths