Collazo-Ortega Margarita, Rosas Ulises, Reyes-Santiago Jerónimo
Departamento de Biología Comparada, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad de México, México.
Jardín Botánico, Instituto de Biología, Universidad Nacional Autónoma de México, Ciudad de México, México.
PLoS Curr. 2017 Mar 31;9:ecurrents.dis.bb66ae4f4f3c6eb118a019a29a9ce80f. doi: 10.1371/currents.dis.bb66ae4f4f3c6eb118a019a29a9ce80f.
In the first months of 2016, the Mexico City Metropolitan Area experienced the worst air pollution crisis in the last decade, prompting drastic short-term solutions by the Mexico City Government and neighboring States. In order to help further the search for long-term sustainable solutions, we felt obliged to immediately release the results of our research regarding the monitoring of carbon sequestration by green roofs. Large-scale naturation, such as the implementation of green roofs, provides a way to partially mitigate the increased carbon dioxide output in urban areas.
Here, we quantified the carbon sequestration capabilities of two ornamental succulent plant species, Sedum dendroideum and Sedum rubrotinctum, which require low maintenance, and little or no irrigation. To obtain a detailed picture of these plants' carbon sequestration capabilities, we measured carbon uptake on the Sedum plants by quantifying carbon dioxide exchange and fixation as organic acids, during the day and across the year, on a green roof located in Southern Mexico City.
The species displayed their typical CAM photosynthetic metabolism. Moreover, our quantification allowed us to conservatively estimate that a newly planted green roof of Sedum sequesters approximately 180,000,000 ppm of carbon dioxide per year in a green roof of 100 square meters in the short term.
The patterns of CAM and carbon dioxide sequestration were highly robust to the fluctuations of temperature and precipitation between seasons, and therefore we speculate that carbon sequestration would be comparable in any given year of a newly planted green roof. Older green roof would require regular trimming to mantain their carbon sink properties, but their carbon sequestration capabilities remain to be quantified. Nevertheless, we propose that Sedum green roofs can be part of the long-term solutions to mitigate the air pollution crisis in the Mexico City Metropolitan area, and other "megacities" with marked seasonal drought.
2016年的头几个月，墨西哥城大都市区经历了过去十年中最严重的空气污染危机，促使墨西哥城政府和周边各州采取了激烈的短期解决方案。为了推动寻求长期可持续解决方案，我们觉得有必要立即公布我们关于绿色屋顶碳固存监测的研究结果。大规模的自然化，比如实施绿色屋顶，为部分缓解城市地区增加的二氧化碳排放提供了一种途径。
在此，我们对两种观赏性多肉植物——垂盆草和虹之玉的碳固存能力进行了量化，这两种植物养护要求低，几乎不需要或完全不需要灌溉。为了详细了解这些植物的碳固存能力，我们通过量化二氧化碳交换以及白天和全年在墨西哥城南部一个绿色屋顶上作为有机酸的碳固定，来测量垂盆草属植物的碳吸收量。
这些物种表现出其典型的景天酸代谢光合作用。此外，我们的量化使我们能够保守估计，在短期内，一个100平方米的新种植垂盆草绿色屋顶每年可固存约1.8亿ppm的二氧化碳。
景天酸代谢和二氧化碳固存模式对季节间温度和降水的波动具有高度的稳定性，因此我们推测，新种植的绿色屋顶在任何一年的碳固存情况都将相当。较老的绿色屋顶需要定期修剪以保持其碳汇特性，但其碳固存能力仍有待量化。尽管如此，我们建议垂盆草绿色屋顶可以成为缓解墨西哥城大都市区以及其他有明显季节性干旱的“特大城市”空气污染危机的长期解决方案的一部分。
