OMEN-SED 1.0: a novel, numerically efficient organic matter sediment diagenesis module for coupling to Earth system models
OMEN-SED 1.0: a novel, numerically efficient organic matter sediment diagenesis module for coupling to Earth system models
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DOI：
10.5194/gmd-11-2649-2018
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发表时间：
2018-07-09
影响因子：
5.1
通讯作者：
Ridgwell, Andy
中科院分区：
文献类型：
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作者：
Huelse, Dominik;Arndt, Sandra;Ridgwell, Andy
我们提出了第一个版本的OMEN-SED（有机质启用沉积模型），一个新的，一维的分析早期成岩模型解决有机质循环和相关的海洋沉积物地球化学动力学设计耦合到地球系统模型。OMEN-SED明确描述了有机质（OM）循环和最重要的末端电子受体（即O-2、NO3、SO4）和甲烷（CH4）、相关还原物质（NH4、H2S）、常量营养素（PO4）和相关孔隙水量（ALK、DIC）的相关动力学。它的反应网络占最重要的初级和次级氧化还原反应，平衡反应，矿物溶解和沉淀，以及吸附和解吸过程与OM动力学，影响溶解和固体物种明确解决在模型中。为了代表一个氧化还原依赖的沉积磷循环，我们还包括一个代表性的铁结合磷和自生钙磷矿物的形成和埋藏。因此，OMEN-SED能够捕捉海洋沉积物成岩动力学的主要特征，因此提供与复杂的数值成岩模型相似的预测能力。然而，它的计算效率允许其耦合到全球地球系统模型，因此在广泛的气候相关的时间尺度上的耦合全球地球化学动力学的调查。本文提供了一个新的沉积物模型，广泛的敏感性分析和OMEN-SED的性能，通过全面的比较，从一个更复杂的数值模型的观测和结果进行了详细的描述。我们发现，固相和溶解孔隙水剖面不同的海洋深度再现具有良好的精度和模拟终端电子受体通量落在全球观测通量的范围内。最后，我们说明了它的应用程序在地球系统模型框架耦合OMEN-SED的地球系统模型cGENIE和调整OM降解速率常数，以优化模拟的海底OM含量的全球观测。我们发现，耦合模型框架的模拟沉积物特性，如OM降解速率，氧渗透深度和沉积物-水界面通量，一般与观测结果吻合良好，并符合人们在全球范围内的预期。OMENSED与地球系统模型相结合，因此是一个强大的工具，不仅有助于阐明底栖-中上层交换过程在各种气候事件的演变和终止中的作用，而且还可以将模型输出与地球上最重要的气候档案沉积记录进行直接比较。
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. O-2, 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, OMENSED 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.