Engineering the Cambrian explosion: the earliest bioturbators as ecosystem engineers

Herringshaw, Liam G.; Callow, Richard H. T.; McIlroy, Duncan

Abstract

By applying modern biological criteria to trace fossil types and assessing burrow morphology, complexity, depth, potential burrow function and the likelihood of bioirrigation, we assign ecosystem engineering impact (EEI) values to the key ichnotaxa in the lowermost Cambrian (Fortunian). Surface traces such as Monomorphichnus have minimal impact on sediment properties and have very low EEI values; quasi-infaunal traces of organisms that were surficial modifiers or biodiffusors, such as Planolites, have moderate EEI values; and deeper infaunal, gallery biodiffusive or upward-conveying/downward-conveying traces, such as Teichichnus and Gyrolithes, have the highest EEI values. The key Cambrian ichnotaxon Treptichnus pedum has a moderate to high EEI value, depending on its functional interpretation. Most of the major functional groups of modern bioturbators are found to have evolved during the earliest Cambrian, including burrow types that are highly likely to have been bioirrigated. In fine-grained (or microbially bound) sedimentary environments, trace-makers of bioirrigated burrows would have had a particularly significant impact, generating advective fluid flow within the sediment for the first time, in marked contrast with the otherwise diffusive porewater systems of the Proterozoic. This innovation is likely to have created significant ecospace and engineered fundamentally new infaunal environments for macrobiotic and microbiotic organisms alike.

Citation

Herringshaw, L. G., Callow, R. H. T., & McIlroy, D. (2017). Engineering the Cambrian explosion: the earliest bioturbators as ecosystem engineers. Geological Society Special Publications, 448(1), 369-382. https://doi.org/10.1144/sp448.18

• Journal Article Type: Article
• Acceptance Date: Jan 23, 2017
• Online Publication Date: Jan 23, 2017
• Publication Date: 2017
• Deposit Date: Feb 4, 2017
• Publicly Available Date: Feb 4, 2017
• Journal: Geological society special publications
• Print ISSN: 0305-8719
• Publisher: Geological Society
• Peer Reviewed: Peer Reviewed
• Volume: 448
• Issue: 1
• Pages: 369-382
• Book Title: Geological Society Special Publication
• DOI: https://doi.org/10.1144/sp448.18
• Keywords: Geology; Ocean Engineering; Water Science and Technology
• Public URL: https://hull-repository.worktribe.com/output/447816
• Publisher URL: http://sp.lyellcollection.org/content/early/2017/01/20/SP448.18.abstract
• Additional Information: This is a copy of an article published in: Geological society special publications, 2017, v.448.
• Contract Date: Feb 4, 2017