Sustainability division, Department for Technology, Management and Economics, Technical University of Denmark, Produktionstorvet, 2800 kgs., Lyngby, Denmark.
Norwegian Institute for Water Research, NIVA Denmark, Copenhagen, Denmark.
Sci Total Environ. 2022 Oct 15;843:156873. doi: 10.1016/j.scitotenv.2022.156873. Epub 2022 Jun 22.
Marine eutrophication and hypoxia caused by excess nutrient availability is a growing environmental problem. In this study, we explore marine nitrogen enrichment in the context of Absolute Environmental Sustainability Assessment (AESA), a method combining life cycle assessment (LCA) with environmental boundaries aiming to compare environmental impacts from an activity (product or system) with the safe operating space (SOS) for the activity. Specifically, we aim to increase the spatial resolution and improve life cycle impact assessment (LCIA) models for marine eutrophication for use in AESAs. By estimating a proxy of the areal extent of eutrophication and hypoxia in coastal large marine ecosystems (LME), we increased model resolution from 66 LMEs in the original LCIA method to 289 coastal LME subsegments and updated relevant LME parameters to the new scale (residence time, bottom water volume, reference O concentration, primary production rates and depths). The new method was tested and validated by comparing the global and spatially differentiated occupation of SOS by global nitrogen emissions with observations and it showed an improved ability to identify critical areas where the SOS is exceeded, in accordance with observations of hypoxic events. Despite limitations such as the estimation of benthic zone volume and low spatial differentiation of environmental boundaries, the method can be used by AESA and LCA practitioners wishing to assess the impact of nitrogen release on marine eutrophication with a higher and more relevant spatial resolution.
海洋富营养化和缺氧是由过量营养物质引起的，这是一个日益严重的环境问题。在本研究中，我们在绝对环境可持续性评估（AESA）的背景下探讨海洋氮富集，AESA 是一种将生命周期评估（LCA）与环境边界相结合的方法，旨在将活动（产品或系统）的环境影响与活动的安全运行空间（SOS）进行比较。具体而言，我们旨在提高海洋富营养化的空间分辨率并改进用于 AESAs 的生命周期影响评估（LCIA）模型。通过估计沿海大型海洋生态系统（LME）中富营养化和缺氧的面积范围的代理，我们将原始 LCIA 方法中的 66 个 LME 的模型分辨率提高到 289 个沿海 LME 子区域，并更新了相关的 LME 参数以适应新的规模（停留时间、底水体积、参考 O 浓度、初级生产力和深度）。通过比较全球氮排放对 SOS 的全球和空间差异化占用与观察结果，新方法得到了测试和验证，并显示出了改进的能力，可以识别 SOS 超过的关键区域，与缺氧事件的观察结果一致。尽管存在一些限制，例如底栖区体积的估计和环境边界的低空间分化，但希望以更高和更相关的空间分辨率评估氮释放对海洋富营养化影响的 AESA 和 LCA 从业者可以使用该方法。
