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Self-sedimentation of phytoplankton blooms in the geologic record |
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| Authors: | Kurt A Grimm Carina B Lange Amarpal S Gill |
| Institution: | a Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada b Scripps Institution of Oceanography, La Jolla, CA 92093-0215, USA c Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, BC V6T 1Z4, Canada |
| Abstract: | Understanding the formation of laminated, organic-rich sediments is an essential topic for researchers interested in fossil fuels, biogeochemical cycles, Earth's environmental history and global change. Biologists have very recently demonstrated that some marine phytoplankton blooms actively govern their own sedimentation by the formation of sticky transparent gels that facilitate rapid aggregation, accelerated sinking and efficient export flux. Here we present fossil evidence of unfragmented, low-diversity phytoplankton assemblages preserved as sedimentary laminae and irregular flocs that are attributable to a similar phytoplankton-driven sedimentary mechanism we term ‘self-sedimentation’. The geological evidence suggests that self-sedimentation precludes significant heterotrophic grazing, propels the formation of some conspicuous hemipelagic sedimentary laminae and results in efficient carbon and opal flux to the sediments. We suggest that the self-sedimentation phenomenon may have broad implications for the geological history of biogeochemical cycling, oceanic ecological dynamics, and abrupt atmospheric/environmental change. Broader recognition of the self-sedimentation phenomenon as explicitly defined here is a prerequisite to testing these unconventional hypotheses. |
| Keywords: | laminated sediments diatoms sedimentary processes paleoecology geophysiology |
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