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Mine tailings pose a health risk for populations and ecosystems in the Southwest; this is why effective, and low-cost solutions for the long term are needed. This work is groundbreaking since little information is available with regards to applying greenhouse studies of phytostabilization to the field for mine tailing remediation. Mine tailings from Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site can be considered one of the worst scenarios due to the extreme conditions which prevent the growth of a vegetation cap. The high concentration of metals, such as arsenic and lead, highly acidic, lack of the nutrients carbon and nitrogen in the soil structure, and low microbial communities are factors that negatively affect plant growth. This project provides practical field-scale applications for the use of phytostabilization, which uses plants to create a vegetation cap that stabilizes metals in the root zone while preventing wind and water erosion in mine tailings. The project is divided into three main studies: (1) the assessment of the translation of successful greenhouse results to the field of phytostabilization using compost-assisted direct planting. This includes the use of different rates of compost as an amendment and different desert native plant species in addition to some potential parameters that could be used as indicators of a successful modification of biochemical and physical environment from a disturbed soil towards a more healthy soil when compost assisted direct planting phytostabilization is used; (2) the second study aims to evaluate the effect of the phytostabilization strategy on reducing windborne transport of particle and metal(loids) following the establishment of the vegetation cap. The results indicate that the vegetation resulted from direct planting decreases dust emissions from IKMHSS mine tailings; and (3) the third study focuses on one of the most important requirements for phytostabilization application in the field, the perf

Drought can affect the capacity of soils to emit and consume biogenic volatile organic compounds (VOCs). Here we show the impact of prolonged drought followed by rewetting and recovery on soil VOC fluxes in an experimental rainforest. Under wet conditions the rainforest soil acts as a net VOC sink, in particular for isoprenoids, carbonyls and alcohols. The sink capacity progressively decreases during drought, and at soil moistures below ~19%, the soil becomes a source of several VOCs. Position specific 13C-pyruvate labeling experiments reveal that soil microbes are responsible for the emissions and that the VOC production is higher during drought. Soil rewetting induces a rapid and short abiotic emission peak of carbonyl compounds, and a slow and long biotic emission peak of sulfur-containing compounds. Results show that, the extended drought periods predicted for tropical rainforest regions will strongly affect soil VOC fluxes thereby impacting atmospheric chemistry and climate.

Severe droughts endanger ecosystem functioning worldwide. We investigated how drought affects carbon and water fluxes as well as soil-plant-atmosphere interactions by tracing 13CO2 and deep water 2H2O label pulses and volatile organic compounds (VOCs) in an enclosed experimental rainforest. Ecosystem dynamics were driven by different plant functional group responses to drought. Drought-sensitive canopy trees dominated total fluxes but also exhibited the strongest response to topsoil drying. Although all canopy-forming trees had access to deep water, these reserves were spared until late in the drought. Belowground carbon transport was slowed, yet allocation of fresh carbon to VOCs remained high. Atmospheric VOC composition reflected increasing stress responses and dynamic soil-plant-atmosphere interactions, potentially affecting atmospheric chemistry and climate feedbacks. These interactions and distinct functional group strategies thus modulate drought impacts and ecosystem susceptibility to climate change.

Severe droughts endanger ecosystem functioning worldwide. We investigated how drought affects carbon and water fluxes as well as soil-plant-atmosphere interactions by tracing 13CO2 and deep water 2H2O label pulses and volatile organic compounds (VOCs) in an enclosed experimental rainforest. Ecosystem dynamics were driven by different plant functional group responses to drought. Drought-sensitive canopy trees dominated total fluxes but also exhibited the strongest response to topsoil drying. Although all canopy-forming trees had access to deep water, these reserves were spared until late in the drought. Belowground carbon transport was slowed, yet allocation of fresh carbon to VOCs remained high. Atmospheric VOC composition reflected increasing stress responses and dynamic soil-plant-atmosphere interactions, potentially affecting atmospheric chemistry and climate feedbacks. These interactions and distinct functional group strategies thus modulate drought impacts and ecosystem susceptibility to climate change.