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Floating treatment wetlands (FTWs) are artificial ecosystems designed to mimic the nutrient removal capabilities of natural wetlands through the hydroponic cultivation of plants on floating rafts, thereby utilizing the process of phytoremediation. This approach provides plants with protection against submersion, creating an optimal environment for the growth of valuable hydroponic crops. To ensure the removal of nutrients absorbed and incorporated into plant biomass from aquatic systems, the implementation of routine plant harvesting serves as an effective management strategy. This practice prevents the decomposition and subsequent release of nutrients back into the water. Furthermore, the cultivation of crops for commercial purposes can serve as an incentive to enhance biomass harvesting and replanting efforts, which may be financially impractical otherwise. This study aimed to assess the growth success and nutrient remediation capacities of five cut-flower species on FTWs in controlled mesocosm systems at Florida International University in Miami, Florida. The surviving species were evaluated based on growth metrics, bloom count, and nutrient removal abilities, specifically for total phosphorus (TP) and total nitrogen (TN). Among the five species tested, only marigold (Tagetes erecta) survived throughout the 12-week trial on the FTWs. The marigold-planted treatment exhibited a significant enhancement in nutrient reduction efficiencies compared to the control treatment, removing 52% more TP and 33% more TN mass from the mesocosm system. This resulted in a nutrient removal rate of 0.062 g of TP ‧ m2 ‧ day−1 and 0.321 g of TN ‧ m2 ‧ day−1 in the marigold-treated mesocosm. Additionally, the marigold treatment yielded an average of 65 market-quality blooms per m2, with mean widths of 6.4±1.8 cm and lengths of 27.6±7.3 cm. Given the substantial nutrient removal and the production of marketable blooms, marigold (Tagetes erecta) shows promising potential as a commercially viable remediating crop cultivated on FTWs in South Florida. Statement of Significance: This study demonstrated that marigolds grew successfully on an FTW, removed a comparable amount of nutrients from the water as other wetland plants tested on FTWs in previous studies, and produced a high number of blooms for market. This species is worth testing at a field scale to see how well they thrive in application. Future studies should increase the thickness of the FTW for roots to anchor better and help stabilize the growth of additional cut-flower species. Specifically, the production of cut-flowers on FTWs in South Florida could take advantage of the floral industry infrastructure in Miami, FL while also helping to address increasing water quality issues in the region.

This study evaluated the ability to improve Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) chl-a retrieval from optically shallow coastal waters by applying algorithms specific to the pixels’ benthic class. The form of the Ocean Color (OC) algorithm was assumed for this study. The operational atmospheric correction producing Level 2 SeaWiFS data was retained since the focus of this study was on establishing the benefit from the alternative specification of the bio-optical algorithm. Benthic class was determined through satellite image-based classification methods. Accuracy of the chl-a algorithms evaluated was determined through comparison with coincident in situ measurements of chl-a. The regionally-tuned models that were allowed to vary by benthic class produced more accurate estimates of chl-a than the single, unified regionally-tuned model. Mean absolute percent difference was approximately 70% for the regionally-tuned, benthic class-specific algorithms. Evaluation of the residuals indicated the potential for further improvement to chl-a estimation through finer characterization of benthic environments. Atmospheric correction procedures specialized to coastal environments were recognized as areas for future improvement as these procedures would improve both classification and algorithm tuning.

High nighttime urban air temperatures increase health risks and economic vulnerability of people globally. While recent studies have highlighted nighttime heat mitigation effects of urban vegetation, the magnitude and variability of vegetation-derived urban nighttime cooling differs greatly among cities. We hypothesize that urban vegetation-derived nighttime air cooling is driven by vegetation density whose effect is regulated by aridity through increasing transpiration. We test this hypothesis by deploying microclimate sensors across eight United States cities and investigating relationships of nighttime air temperature and urban vegetation throughout a summer season. Urban vegetation decreased nighttime air temperature in all cities. Vegetation cooling magnitudes increased as a function of aridity, resulting in the lowest cooling magnitude of 1.4 °C in the most humid city, Miami, FL, and 5.6 °C in the most arid city, Las Vegas, NV. Consistent with the differences among cities, the cooling effect increased during heat waves in all cities. For cities that experience a summer monsoon, Phoenix and Tucson, AZ, the cooling magnitude was larger during the more arid pre-monsoon season than during the more humid monsoon period. Our results place the large differences among previous measurements of vegetation nighttime urban cooling into a coherent physiological framework dependent on plant transpiration. This work informs urban heat risk planning by providing a framework for using urban vegetation as an environmental justice tool and can help identify where and when urban vegetation has the largest effect on mitigating nighttime temperatures.