DISSERTATION RESEARCH: Will Ecosystem Recovery From Acid Precipitation Jeopardize Soil Carbon Storage?

论文研究：酸沉淀中的生态系统恢复是否会危及土壤碳储存？

• 批准号: 1701920
• 负责人: Emily Bernhardt
• 金额: $ 2.05万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1701920&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Will; Ecosystem; Recovery

While acid rain has significantly decreased across the United States over the past thirty years, many forested ecosystems are only beginning to recover, with full recovery expected to take decades to centuries. Recent evidence suggests that, while forests will grow better as they recover from acid rain, the soil in forests may also lose a substantial amount of the carbon and nutrients. In this Doctoral Dissertation Improvement Grant (DDIG) project, the student is working to understand the mechanisms by which forest recovery from acid rain may increase the vulnerability of soil organic matter that contains soil carbon and nutrients. The investigators are particularly interested in understanding how rising soil acidity and calcium content may alter the solubility and lability (decomposability) of soil carbon. The project will test this by studying the physical, chemical and microbiological properties of soils in response to changing acidity. This research is necessary to predict future trends of forest growth and carbon storage throughout the Northeastern United States. To facilitate and inform evidence-based management decisions, this research will be incorporated into a web-based application that is geared toward letting the general public explore and understand long-term ecological data. To examine the mechanisms by which ecosystem recovery from acid rain may alter soil organic matter (SOM) dynamics, the researchers will perform a long-term greenhouse mesocosm experiment. Soils will be collected from Hubbard Brook Experimental Forest, a Northeastern hardwood forest that is impacted by acid rain. The team will reconstruct soil mesocosms by horizon, both with and without sugar maple seedlings, a co-dominant species in the forest where the soils were obtained. Soils will be experimentally amended to increase soil pH and Ca in a fully factorial design. The student will measure SOM solubility and microbial respiration of SOM to determine the responses of SOM pools to these treatments. In addition, researchers will measure proximate mechanisms of SOM dynamics (Aluminum-SOM complexation, soil exoenzyme activity, bacterial:fungal microbial biomass ratios, etc.) that may drive changes to SOM solubility and microbial respiration. These measurements will be compared between planted and unplanted mesocosm to identify possible plant-mediated effects on SOM dynamics.

尽管在过去的三十年中，整个美国的酸雨已大大减少，但许多森林生态系统才刚刚开始恢复，预计完全恢复将需要数十年到几个世纪。最近的证据表明，尽管森林从酸雨中恢复过来时会变得更好，但森林中的土壤也可能会损失大量的碳和养分。 在该博士学位论文改善赠款（DDIG）项目中，学生正在努力了解从酸雨中恢复森林可能会增加含有土壤碳和养分的土壤有机物的脆弱性的机制。研究人员特别有兴趣了解土壤酸度和钙含量上升如何改变土壤碳的溶解度和衰老（可分解性）。 该项目将通过研究土壤的物理，化学和微生物学特性来响应变化的酸度来测试这一点。 这项研究对于预测整个美国东北部森林增长和碳储存的未来趋势是必要的。为了促进并为基于证据的管理决策提供信息，该研究将纳入基于Web的应用程序中，该应用程序旨在让公众探索和理解长期的生态数据。为了检查生态系统从酸雨中恢复可能改变土壤有机物（SOM）动力学的机制，研究人员将进行长期的温室中cosm介体实验。土壤将从哈伯德·布鲁克（Hubbard Brook）实验森林中收集，这是一种受酸雨影响的东北硬木森林。该团队将通过有或没有糖枫幼苗的地平线重建土壤中心，这是获得土壤的森林中的共同主导物种。在完全阶乘设计中，将对土壤进行实验修改，以增加土壤pH和Ca。学生将测量SOM的SOM溶解度和微生物呼吸，以确定SOM池对这些治疗的反应。此外，研究人员将测量SOM动力学的近端机制（铝 - Som络合，土壤外酶活性，细菌：真菌微生物生物量比等），可能会导致SOM溶解度和微生物呼吸的变化。将在种植和未种植的中验之间比较这些测量值，以鉴定植物介导的对SOM动力学的影响。