Temporal constraints on lateral organic matter transport along a coastal mud belt

Bao, R., Zhao, M., McNichol, A., Galy, V., McIntyre, C. , Haghipour, N. and Eglinton, T. I. (2019) Temporal constraints on lateral organic matter transport along a coastal mud belt. Organic Geochemistry, 128, pp. 86-93. (doi: 10.1016/j.orggeochem.2019.01.007)

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Abstract

Constraints on timescales of lateral transport of organic carbon (OC) over continental shelves and associated influences on the distribution and abundance of sedimentary OC remain sparse. Preferential degradation of labile, young OC during lateral transport results in apparent “diagenetic aging“ of OC. Additionally, sediment translocation can also result in ”transport time-associated aging“ of associated organic matter (OM) as a function of the lateral transport time (LTT). Here, we use a coupled thermal decomposition and radiocarbon (14C) approach to constrain timescales of lateral transport and concomitant loss of OC associated with different grain size fractions of sediments collected from two locations ∼275 km apart along a dispersal pathway on the inner shelf of the East China Sea. The 14C age contrasts between corresponding thermal fractions are used to distinguish these two components of sedimentary OM “aging”. To minimize interferences from hydrodynamic sorting and diagenetic aging of OC accompanying lateral transport, we assess 14C age differences of decomposition products from the most thermally-refractory OC components associated with specific grain size fractions between locations. We show that LTTs vary among different grain size fractions, and examine relationships between LTTs and sedimentary OC loss in order to assess the decomposition of OC as a consequence of lateral transport. We suggest that the decomposition of OC associated with protracted lateral transport exerts a strong influence on OC burial efficiency, with broad implications for carbon cycling over continental shelves.

Item Type:Articles
Additional Information:This study was supported by Doc. Mobility fellowship (No. P1EZP2_159064, R.B.) from the Swiss National Science Foundation (SNSF), the SNSF “CAPS-LOCK” project 200021_140850 (T.I.E.), the National Natural Science Foundation of China (No. 41520104009 and 41630966, M.Z.) and the “111” project (B13030).
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Mcintyre, Dr Cameron
Authors: Bao, R., Zhao, M., McNichol, A., Galy, V., McIntyre, C., Haghipour, N., and Eglinton, T. I.
College/School:College of Science and Engineering > Scottish Universities Environmental Research Centre
Journal Name:Organic Geochemistry
Publisher:Elsevier
ISSN:0146-6380
ISSN (Online):1873-5290
Published Online:17 January 2019
Copyright Holders:Copyright © 2019 The Authors
First Published:First published in Organic Geochemistry 128: 86-93
Publisher Policy:Reproduced under a Creative Commons License

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