Unified concepts for understanding and modelling turnover of dissolved organic matter from freshwaters to the ocean: the UniDOM model
Unified concepts for understanding and modelling turnover of dissolved organic matter from freshwaters to the ocean: the UniDOM model
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DOI：
10.1007/s10533-019-00621-1
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发表时间：
2019-12-01
期刊：
影响因子：
4
通讯作者：
Waska, H.
中科院分区：
文献类型：
--
作者：
Anderson, T. R.;Rowe, E. C.;Waska, H.
溶解有机物（DOM）在陆地-海洋-水连续体（LOAC）中的迁移是全球碳收支的一个重要组成部分，但人们对其了解甚少。考虑到DOM在这些对比鲜明的环境中循环的复杂性，探索和量化这种流量是一个重大的挑战。我们开发了一个新的模型，UniDOM，统一的概念，状态变量和参数化的DOM营业额在LOAC。陆地DOM分为两个池，T-1（强紫外线吸收）和T-2（非或弱紫外线吸收），它们对微生物消耗、光氧化和絮凝表现出截然不同的反应。提供的数据表明，这些样本池可根据特定UV吸光度（苏瓦）进行常规测量。此外，还定义了一个自生DOM池，以解释水生DOM的产生。UniDOM的一个新的方面是，光氧化和微生物周转率的参数作为DOM年龄的反函数。模型结果表明，类似于5%的DOM起源于流可能会渗透到公海，是敏感的参数化，以及分配到营业额的新鲜生产的DOM率。絮凝DOM营业额的预测贡献是非常低的，虽然在UniDOM这个过程的机械表示被认为是无法实现的，因为所涉及的复杂性。我们的工作突出了需要不断研究的机械理解和速率的光氧化，微生物的消耗和絮凝DOM在不同的环境中的LOAC，沿着发展的模型的基础上统一的概念和参数化。
The transport of dissolved organic matter (DOM) across the land-ocean-aquatic-continuum (LOAC), from freshwater to the ocean, is an important yet poorly understood component of the global carbon budget. Exploring and quantifying this flux is a significant challenge given the complexities of DOM cycling across these contrasting environments. We developed a new model, UniDOM, that unifies concepts, state variables and parameterisations of DOM turnover across the LOAC. Terrigenous DOM is divided into two pools, T-1 (strongly-UV-absorbing) and T-2 (non- or weakly-UV-absorbing), that exhibit contrasting responses to microbial consumption, photooxidation and flocculation. Data are presented to show that these pools are amenable to routine measurement based on specific UV absorbance (SUVA). In addition, an autochtonous DOM pool is defined to account for aquatic DOM production. A novel aspect of UniDOM is that rates of photooxidation and microbial turnover are parameterised as an inverse function of DOM age. Model results, which indicate that similar to 5% of the DOM originating in streams may penetrate into the open ocean, are sensitive to this parameterisation, as well as rates assigned to turnover of freshly-produced DOM. The predicted contribution of flocculation to DOM turnover is remarkably low, although a mechanistic representation of this process in UniDOM was considered unachievable because of the complexities involved. Our work highlights the need for ongoing research into the mechanistic understanding and rates of photooxidation, microbial consumption and flocculation of DOM across the different environments of the LOAC, along with the development of models based on unified concepts and parameterisations.