COLLABORATIVE RESEARCH: Photodegredation in deserts: litter optical and structural considerations

碳循环模型用于评估未来碳政策情景将如何影响大气碳库和气候。这些模型的准确性取决于我们对碳循环主要途径的理解。其中一个途径，即死亡植物材料（垃圾）的腐烂，每年向大气中释放的碳比燃烧化石燃料释放的碳还要多。森林中的凋落物腐烂是相当好的理解，但在沙漠中凋落物腐烂的速度和时间模式是不同的。直射阳光对凋落物的影响可能会增加腐烂率，而缺乏水分可能会减少微生物的活动，降低腐烂率。该项目将测试沙漠植物产生的凋落物的光学特性是否有助于凋落物腐烂的不同模式。实验室和实地实验将用于测试阳光作为垃圾腐烂剂相对于其他机制（如微生物活动）的重要性。这项研究将在索诺兰沙漠进行，将有助于我们了解沙漠和其他垃圾暴露在强烈阳光下的生态系统中的碳循环（例如草地和农业系统）。研究人员将开发一个网站，其中包含K12学生的垃圾分解指南，帮助教师进行垃圾分解实验的配套指南，他们将邀请K12教师参与这项实验。该项目将为K12学生和教师以及本科生和研究生提供研究经验。

Carbon cycle models are used to assess how future carbon policy scenarios will influence atmospheric carbon pools and climate. The accuracy of those models depends on our understanding of major pathways in the carbon cycle. One such pathway, the decay of dead plant material (litter), is responsible for releasing more carbon into the atmosphere each year than the combustion of fossil fuel. Litter decay in forests is reasonably well understood, but both the rate and temporal pattern of litter decay are different in deserts. The effects of direct sunlight on litter may increase the rate of decay, while the lack of moisture may reduce microbial activity and decrease the decay rate. This project will test whether the optical properties of litter produced by desert plants contribute to the different pattern of litter decay. Laboratory and field experiments will be used to test the importance of sunlight as an agent of litter decay relative to other mechanisms such as microbial activity. This research, which will be conducted in the Sonoran Desert, will contribute to our understanding of carbon cycling in deserts and in other ecosystems where litter is exposed to intense sunlight (e.g. grasslands and agricultural systems).The investigators will develop a website that contains a guide to litter decomposition for K12 students, a companion guide to aid teachers in conducting litter decomposition experiments, and they will solicit K12 teachers to take part in this experiment. This project will provide research experience for K12 students and teachers, and undergraduate and graduate students.