Disturb, distort, destroy – how burrowing organisms bias paleoclimatic time series
Journal
Ichnos
Journal Volume
32
Journal Issue
2
Start Page
73
End Page
83
ISSN
1042-0940
1563-5236
Date Issued
2025-04-03
Author(s)
Abstract
As our reconstructions of past climates and environments become ever more refined and detailed, the fidelity of the sedimentary archives becomes increasingly important. When paleoceanographic reconstructions now routinely strive for millennial‑ or even centennial‑scale resolution, the effects of sediment mixing and transport by benthic organisms can range from smaller disturbances to outright destruction. Apart from the obvious smoothing and damping of paleoenvironmental and paleoclimatic proxy signals, the mixing and vertical shifting of material can introduce age errors ranging from thousands to even tens of thousands of years. Moreover, in combination with differences in size, composition, or abundance of the proxy carriers in the sediment, phase shifts may be introduced between different proxy signals. The low visibility of trace fossils and bioturbation in fresh core material make them easily overlooked, but novel techniques now allow us to assess their impact on sediment reliability. For example, computed tomography scanning now enables a detailed assessment of both bioturbation and deep‑reaching discrete trace fossils before subsampling, and new developments in analytical performance now render radiocarbon dating of single foraminifera possible. Combined, these approaches permit high‑resolution time series to be extracted even from heavily bioturbated sediments.
Subjects
bioturbation
dating error
mixed layer
oxygen isotopes
paleoceanography
time series
Zoophycos
Publisher
Informa UK Limited
Type
journal article