SG: Can green infrastructure maximize ecosystem processes related to nitrogen?

氮污染造成许多环境和人类健康问题。其中包括有害的藻华、酸雨和烟雾。在城市中，化石燃料的燃烧和施肥会向雨水中添加大量的氮。城市基础设施将雨水输送到下游，这可能会导致过量的氮污染下游生态系统。基于自然的设计，利用生态过程去除雨水中的氮，可能会提供一个解决方案。这些绿色基础设施设计在全球城市中很受欢迎。然而，其有效性仍存在疑问。绿色基础设施设计是否应该尽可能模仿自然生态系统？或者土壤和物种的新组合能否更有效地减轻污染？本研究将通过研究犹他州盐湖城的几种雨水管理设施来寻求这些问题的答案。这项研究的结果将为雨水管理系统的设计提供有用的指导。它还具有促进对氮循环的基本了解的潜力。研究人员还将开展广泛的公众宣传和教育活动，以强调城市空间中生态过程的重要性。科学界目前缺乏一个理论框架来指导最大化氮保留的生态系统设计。 这主要是由于生态系统中氮循环的复杂性。研究人员建议量化生态系统科学的两个关键范式对氮保留的相对影响：生物多样性生态系统功能和热力学生态化学计量。该项目将涉及在两组复制的雨水管理实验设施以及邻近自然区域的复制地块中量化活动规模和季节规模的氮保留过程（微生物和植物吸收、植物生物量和土壤氮积累以及永久气体去除）的速率。第一个实验设施包括九块种植有三个水平植物功能多样性的地块。第二个包括八个地块，具有两个层次的植物群落组成：观赏植物与本地、耐旱物种。 研究人员推测，如果与快速资源获取相关的生理性状是氮循环的重要驱动因素，那么具有高植物多样性和/或耐旱性状的地块将具有更高的氮保留率。此外，研究人员假设，如果生物多样性是这些过程的重要驱动因素，那么不同地块之间以及随着时间的推移，地块建立后微生物群落多样性的变化将与更高的氮固定和反硝化相关。相反，如果生物多样性不是生态系统规模氮通量的重要驱动因素，我们预计保留率遵循热力学和化学计量模型，而植物群落之间没有显着差异。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nitrogen pollution causes many environmental and human health problems. These include harmful algal blooms, acid rain and smog. In cities, fossil fuel burning and fertilizer application add large amounts of nitrogen to stormwater. City infrastructure carries stormwater downstream, which may pollute downstream ecosystems with excess nitrogen. Nature-based designs that use ecological processes to remove nitrogen from stormwater may provide a solution. These green infrastructure designs are popular in cities globally. Questions remain, however, about their effectiveness. Should green infrastructure design mimic natural ecosystems as closely as possible? Or can new combinations of soils and species more effectively mitigate pollution? This research will seek answers to these questions by studying several types of stormwater management facilities in Salt Lake City, UT. Results from this research will provide useful guidance to the design of stormwater management systems. It also has the potential to advance fundamental understanding of the nitrogen cycle. Researchers will also conduct extensive public outreach and educational activities to highlight the importance of ecological processes in urban spaces.The scientific community currently lacks a theoretical framework to guide design of ecosystems that maximize nitrogen retention. This is due largely to the complexity of nitrogen cycling in ecosystems. The researchers propose to quantify the relative influence of two key paradigms of ecosystem science on nitrogen retention: biodiversity-ecosystem function and thermodynamic ecological stoichiometry. The project will involve quantifying rates of nitrogen retention processes (microbial & plant uptake, plant biomass and soil nitrogen accumulation, and permanent gaseous removal) over event-scale and seasonal-scale in two sets of replicated stormwater management experimental facilities, as well as replicate plots in an adjacent natural area. The first experimental facility includes nine plots planted with three levels of plant functional diversity. The second includes eight plots with two levels of plant community composition: ornamental vs. native, xeric-adapted species. Researchers hypothesize that plots with high plant diversity and/or xeric-adapted traits will have higher nitrogen retention if physiological traits related to rapid resource acquisition are an important driver of nitrogen cycling. Further, researchers hypothesize that variation in microbial community diversity across plots and over time following plot establishment will correlate with higher nitrogen immobilization and denitrification if biodiversity is an important driver of these processes. Conversely, if biodiversity is not an important driver of ecosystem scale nitrogen fluxes, we expect to find retention rates follow thermodynamic and stoichiometric models without significant variation across plant communities.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.