Author:
Hülse Dominik,Arndt Sandra,Daines Stuart,Regnier Pierre,Ridgwell Andy
Abstract
Abstract. We present the first version of
OMEN-SED (Organic Matter ENabled SEDiment model), a new, one-dimensional
analytical early diagenetic model resolving organic matter cycling and
the associated biogeochemical dynamics in marine sediments designed to be coupled
to Earth system models. OMEN-SED explicitly describes organic matter
(OM) cycling and the associated dynamics of the most important
terminal electron acceptors (i.e. O2 , NO3, SO4) and
methane (CH4), related reduced substances (NH4, H2S),
macronutrients (PO4) and associated pore water quantities
(ALK, DIC). Its reaction network accounts for the most
important primary and secondary redox reactions, equilibrium reactions,
mineral dissolution and precipitation, as well as adsorption and desorption
processes associated with OM dynamics that affect the dissolved and solid
species explicitly resolved in the model. To represent a redox-dependent
sedimentary P cycle we also include a representation of the formation and
burial of Fe-bound P and authigenic Ca–P minerals. Thus, OMEN-SED is able to
capture the main features of diagenetic dynamics in marine sediments and
therefore offers similar predictive abilities as a complex, numerical
diagenetic model. Yet, its computational efficiency allows for its coupling to
global Earth system models and therefore the investigation of coupled global
biogeochemical dynamics over a wide range of climate-relevant timescales.
This paper provides a detailed description of the new sediment model, an
extensive sensitivity analysis and an evaluation of OMEN-SED's
performance through comprehensive comparisons with observations and results
from a more complex numerical model. We find that solid-phase and dissolved pore
water profiles for different ocean depths are reproduced with good accuracy
and simulated terminal electron acceptor fluxes fall well within the range of
globally observed fluxes. Finally, we illustrate its application in an Earth
system model framework by coupling OMEN-SED to the Earth system model cGENIE
and tune the OM degradation rate constants to optimise the fit of simulated
benthic OM contents to global observations. We find that the simulated sediment
characteristics of the coupled model framework, such as OM degradation rates,
oxygen penetration depths and sediment–water interface fluxes, are generally
in good agreement with observations and in line with what one would expect on
a global scale. Coupled to an Earth system model, OMEN-SED is thus a powerful
tool that will not only help elucidate the role of benthic–pelagic exchange
processes in the evolution and the termination of a wide
range of climate events, but will also allow for a direct comparison of model
output with the sedimentary record – the most important climate archive on
Earth.
Funder
NERC Environmental Bioinformatics Centre
Reference125 articles.
1. Aguilera, D. R., Jourabchi, P., Spiteri, C., and Regnier, P.: A
knowledge-based
reactive transport approach for the simulation of biogeochemical dynamics in
Earth systems, Geochem. Geophy. Geosy., 6, Q07012,
https://doi.org/10.1029/2004GC000899,
2005. a, b, c
2. Aller, R. C.: The importance of relict burrow structures and burrow
irrigation
in controlling sedimentary solute distributions, Geochim. Cosmochim.
Ac., 48, 1929–1934, https://doi.org/10.1016/0016-7037(84)90375-2,
1984. a
3. Aller, R. C.: Benthic fauna and biogeochemical processes in marine sediments:
the role of burrow structures, in: Nitrogen cycling in coastal marine
environments, edited by: Blackburn, T. and Sorensen, J., Scope,
Chichester, 301–338, 1988. a
4. Archer, D.: A data-driven model of the global calcite lysocline, Global
Biogeochem. Cy., 10, 511–526, https://doi.org/10.1029/96GB01521,
1996. a, b, c, d, e
5. Archer, D. and Devol, A.: Benthic oxygen fluxes on the Washington shelf and
slope: A comparison of in situ microelectrode and chamber flux
measurements, Limnol. Oceanogr., 37, 614–629,
https://doi.org/10.4319/lo.1992.37.3.0614,
1992. a
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