SHIMMER (1.0): a novel mathematical model for microbial and biogeochemical dynamics in glacier forefield ecosystems
SHIMMER (1.0): a novel mathematical model for microbial and biogeochemical dynamics in glacier forefield ecosystems
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DOI：
10.5194/gmd-8-3441-2015
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发表时间：
2015-01-01
影响因子：
5.1
通讯作者：
Arndt, S.
中科院分区：
文献类型：
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作者：
Bradley, J. A.;Anesio, A. M.;Arndt, S.
SHIMMER（Soil Microbial Ecosystem Response）是一个新的数值模拟框架，旨在模拟冰川前缘土壤生态系统发育初期的微生物动力学和土壤地球化学循环。然而，它也可以转移到其他极端生态系统类型（如沙漠土壤或冰川表面）。模型开发的基本原理来自于几十年来在冰川前沿的经验观测，并实现了定量和过程为重点的方法。在这里，我们提供了一个详细的描述SHIMMER，测试其性能在两个案例研究前田：达玛冰川（瑞士）和阿萨巴斯卡冰川（加拿大）和敏感性分析，以确定最敏感和无约束的模型参数。结果表明，微生物生物量的积累主要取决于微生物生长和死亡速率常数、Q（10）值、微生物生物量活性组分和有机质反应性的变化。该模型正确地预测了在两个案例研究系统的前田演替的初始阶段观察到的微生物生物量的快速积累。初级生产是负责不稳定的基板，随后支持异养生长的初始积累。然而，有机质和固氮的异地贡献，在维持这种生产力是重要的。SHIMMER的开发和应用还强调了这些系统需要进一步实证研究的方面：量化营养预算和生物地球化学速率、探索季节性和微生物生长和细胞死亡。这将导致更多的了解如何冰川前沿有助于全球地球化学循环和气候下未来的冰退缩。
SHIMMER (Soil biogeocHemIcal Model for Microbial Ecosystem Response) is a new numerical modelling framework designed to simulate microbial dynamics and biogeochemical cycling during initial ecosystem development in glacier forefield soils. However, it is also transferable to other extreme ecosystem types (such as desert soils or the surface of glaciers). The rationale for model development arises from decades of empirical observations in glacier forefields, and enables a quantitative and process focussed approach. Here, we provide a detailed description of SHIMMER, test its performance in two case study forefields: the Damma Glacier (Switzerland) and the Athabasca Glacier (Canada) and analyse sensitivity to identify the most sensitive and unconstrained model parameters. Results show that the accumulation of microbial biomass is highly dependent on variation in microbial growth and death rate constants, Q(10) values, the active fraction of microbial biomass and the reactivity of organic matter. The model correctly predicts the rapid accumulation of microbial biomass observed during the initial stages of succession in the forefields of both the case study systems. Primary production is responsible for the initial build-up of labile substrate that subsequently supports heterotrophic growth. However, allochthonous contributions of organic matter, and nitrogen fixation, are important in sustaining this productivity. The development and application of SHIMMER also highlights aspects of these systems that require further empirical research: quantifying nutrient budgets and biogeochemical rates, exploring seasonality and microbial growth and cell death. This will lead to increased understanding of how glacier forefields contribute to global biogeochemical cycling and climate under future ice retreat.