Phosphorus Regulation of Decomposition, Microbial Dynamics, and Foliar Chemistry in Moist Tropical Forests

潮湿热带森林中磷的分解、微生物动力学和叶化学的调节

• 批准号: 0089447
• 负责人: Alan Townsend
• 金额: $ 57.09万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-06-01 至 2005-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0089447&HistoricalAwards=false
• 关键词: Phosphorus; Regulation; Decomposition; Microbial; Dynamics

Despite a widespread belief that low phosphorus (P) availability is a strong constraint on ecosystem dynamics in many tropical forests, direct tests of this belief are rare, and understanding of tropical forest biogeochemistry remains relatively poor. To test this assumption, a phosphorus fertilization experiment will be conducted in lowland moist tropical rainforests located on extremely old soils in southwest Costa Rica. Preliminary work has shown that P availability is poor in these systems, and that low P availability appears to limit the activity of soil microorganisms. This research will follow up on these preliminary data through the use of long-term P fertilization plots which span gradients in soil age and which include at least 3 different dominant canopy trees in these forests. Each individual plot will contain a mature canopy tree at its center, and the trees will contain permanent climbing ropes to provide access to live canopy leaves. In addition to the effects of fertilization on canopy chemistry, the research will monitor processes within the soil and on the forest floor, including soil respiration, litter decomposition, analyses of microbial function and composition, and a suite of soil biogeochemical analyses. This work will advance understanding of how P availability regulates ecosystem processes in lowland tropical forests, with an emphasis on the poorly understood microbial communities. In addition, the investigators seek to maintain these fertilization plots for the long term, and to facilitate collaboration from other scientists interested in using them.

尽管人们普遍认为，低磷（P）的可用性是一个强有力的约束在许多热带森林的生态系统动态，这种信念的直接测试是罕见的，热带森林生态地球化学的理解仍然相对较差。为了验证这一假设，磷肥施肥实验将在哥斯达黎加西南部极古老土壤上的低地潮湿热带雨林中进行。初步研究表明，在这些系统中，磷的有效性很差，低磷的有效性似乎限制了土壤微生物的活性。这项研究将通过使用长期的磷肥施肥图，其中包括至少3个不同的优势冠层树木在这些森林中的土壤年龄梯度，这些初步数据的后续行动。每个单独的地块将包含一个成熟的树冠树在其中心，树木将包含永久攀登绳索，以提供访问活树冠叶。除了施肥对树冠化学的影响外，这项研究还将监测土壤和森林地面的过程，包括土壤呼吸、凋落物分解、微生物功能和组成分析以及一套土壤生物地球化学分析。这项工作将促进了解磷的可用性如何调节生态系统过程中的低地热带森林，重点是了解甚少的微生物群落。此外，研究人员试图长期维持这些施肥地块，并促进其他有兴趣使用它们的科学家的合作。