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Abstract
Sediment gravity flows are the primary process by which sediment and
organic carbon are transported from the continental margin to the deep
ocean. Up to 40% of the total marine organic carbon pool is represented
by cohesive extracellular polymeric substances (EPS) produced by
microorganisms. The effect of these polymers on sediment gravity flows
has not been investigated, despite the economic and societal importance
of these flows. We present the first EPS concentrations measured in
deep-sea sediment, combined with novel laboratory data that offer
insights into the modulation of the dynamics of clay-laden, physically
cohesive sediment gravity flows by biological cohesion. We show that EPS
can profoundly affect the character, evolution, and runout of sediment
gravity flows and are as prevalent in deep oceans as in shallow seas.
Transitional and laminar plug flows are more susceptible to EPS-induced
changes in flow properties than turbulent flows. At relatively low
concentrations, EPS markedly decrease the head velocity and runout
distance of transitional flows. This biological cohesion is greater, per
unit weight, than the physical cohesion of cohesive clay and may exert a
stronger control on flow behavior. These results significantly improve
our understanding of the effects of an unrealized biological component
of sediment gravity flows. The implications are wide ranging and may
influence predictive models of sediment gravity flows and advance our
understanding about the ways in which these flows transport and bury
organic carbon globally.
Original language | English |
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Pages (from-to) | 72-76 |
Journal | Geology |
Volume | 48 |
Issue number | 1 |
Early online date | 19 Nov 2019 |
DOIs | |
Publication status | Published - 1 Jan 2020 |
Fingerprint
Dive into the research topics of 'Biomediation of submarine sediment gravity flow dynamics'. Together they form a unique fingerprint.Projects
- 1 Finished
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COHBED: Realistic Sedimentary Bedform Prediction: Incorporating Physical and Biological Cohesion
Paterson, D. (PI) & Kinnear, R. J. (CoI)
1/01/12 → 31/10/15
Project: Standard