A Decade of Ecosystem-Scale Research at an Aridland Constructed Treatment Wetland
A Decade of Ecosystem-Scale Research at an Aridland Constructed Treatment Wetland
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DOI：
10.3389/fenvs.2020.576936
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发表时间：
2020-10-16
影响因子：
4.6
通讯作者：
Childers, Daniel L.
中科院分区：
文献类型：
--
作者：
Childers, Daniel L.
城市越来越多地追求更具弹性和可持续的未来。一种方法是增加城市生态基础设施(UEI)的使用，包括人工处理湿地(CTW)。这一战略对于水资源稀缺的旱地城市尤为重要。在这篇论文中，我综合了在美国亚利桑那州凤凰城的Tres Rios CTW进行的近10年的系统级研究。自2011年7月以来，一个由数十名学生志愿者组成的研究小组一直在采样草本植物的生物量和生产力、水质、蒸腾速率和水生新陈代谢。我们还量化了每年的地下生物量和植物组织养分含量，并测量了2012至2014年的温室气体通量。我们的夏季生物量峰值是文献中报道的最高值之一，高蒸腾速率与这种生物量有关。利用我们的全系统水量平衡和示踪研究，我们记录了地表水从邻近的开阔水域缓慢进入沼泽的过程，这是由蒸腾损失驱动的，我们将其称为“生物潮”。根据我们对整个系统和植被沼泽的氮(N)收支，我们发现植被沼泽每年大约50%的氮吸收是由通过生物潮汐进入的新水驱动的。我们的水生代谢采样表明，与自养水柱相关的N吸收大约是植被覆盖的沼泽年平均N吸收的27%。沼泽是空气-水界面CH4和N2O的来源，植物是CH4的净源，但N2O的净汇。我们的综合通量估计表明，由于这种植物介导的N2O净吸收，特雷斯·里奥斯沼泽是温室气体当量的净汇。最后，多年来，我们的Tres Rios CTW项目为数十名学生和年轻人提供了一个在野外和实验室体验生态研究的平台。
Cities are increasingly pursuing more resilient and sustainable futures. One way to do so is by the increased use of Urban Ecological Infrastructure (UEI), including constructed treatment wetlands (CTW). This strategy is particularly important for aridland cities with scarce water resources. In this paper I synthesize nearly 10 years of systems-level research at the Tres Rios CTW in Phoenix, AZ, United States. Since July 2011, a research team that includes dozens of student volunteers has been sampling for herbaceous biomass and productivity, water quality, transpiration rates, and aquatic metabolism. We also quantify belowground biomass and plant tissue nutrient content annually, and measured greenhouse gas fluxes from 2012 to 2014. Our peak summer biomass values are among the highest reported in the literature, and high rates of transpiration are associated with this biomass. Using our whole-system water budgets and tracer studies we have documented a slow movement of surface water into the marsh from adjacent open water areas that is driven by transpirational losses and that we refer to as the "biological tide." With our nitrogen (N) budgets for the whole system and the vegetated marsh we showed that roughly 50% of the annual N uptake by the vegetated marsh is driven by new water entering via this biological tide. Our aquatic metabolism sampling suggested that the N uptake associated with the autotrophic water column was roughly 27% of the average annual N uptake by the vegetated marsh. The marsh is a source of CH4 and N2O across the air-water interface and the plants are a net source of CH4 but a net sink for N2O. Our combined flux estimates suggest that the Tres Rios marshes are a net sink for greenhouse gas equivalents because of this plant-mediated net uptake of N2O. Finally, over the years our Tres Rios CTW project has provided a platform for dozens of students and young people to experience ecological research, both in the field and in the lab.