REU: Belowground Processes and Nitrogen Availability Across a Dynamic, Nutrient Poor, Barrier Island Landscape

REU：动态、营养贫乏、障壁岛景观中的地下过程和氮可用性

• 批准号: 9007899
• 负责人: Frank Day
• 金额: $ 40.65万
• 依托单位: Old Dominion University Research Foundation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-06-01 至 1993-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9007899&HistoricalAwards=false
• 关键词: REU; Belowground; Processes; Nitrogen; Availability

Past studies have suggested that nutrient>.>poor sites have greater nutrient immobilization in the litter, greater belowground allocation of biomass, and slower decay; all resulting in more conservative nutrient cycles. Most of these studies focused on forested ecosystems with minimal emphasis on belowground dynamics. The primary objectives of this new research project are (1) to quantify the relationships between C and N availability and belowground dynamics across a nutrient-poor, dynamic, barrier island landscape; (2) to quantify the influences of microtopography, successional age and microenvironmental interfaces (caused by fluctuating groundwater levels) on belowground processes; and (3) to refine and extend the application of newer techniques for belowground research. The research will be conducted along an established transect incommunities 65, 35, 25 and 5 years old on the accreting end of Hog Island on NSF's Virginia Coast Reserve Long-Term Ecological Research (LTER) site. Nitrogen amended and unamended plots will be used to test the effects of nitrogen availability on belowground processes. Root production, root decomposition, nitrogen immobilization rates in root litter, mineralization rates, and root and soil nitrogen content will be measured in the treatment and control plots. Reciprocal litter bag transplants will test the degree of control of root decomposition by external nitrogen supply versus litter quality. All processes will be evaluated in relation to microenvironmental conditions and successional age along the transect and vertically within the soil profile. The application of minirhizotrons in barrier island ecosystems will also be tested. Results from the project will be of fundamental importance to the basic ecological resolution of the governance of nutrient dynamics and plant community composition in nutrient-poor ecosystems. Additionally, the work should produce insights to assist in better management of barrier islands and beachfronts, areas where the interests of conservation, recreation and commercial development often collide. The principal investigator is well qualified, and institutional facilities are adequate to the task. Integration of this new project with the ongoing research program of the Virginia Coast Reserve LTER project will result in productive augmentation of both efforts.

过去的研究表明，营养bbb。>差地凋落物的养分固定更大，生物量的地下分配更大，腐烂速度更慢；所有这些都导致了更保守的营养循环。这些研究大多集中在森林生态系统上，很少强调地下动态。这个新研究项目的主要目标是：(1)在一个营养贫乏、动态的堰洲岛景观中，量化C和N可用性与地下动态之间的关系；(2)量化微地形、演替年龄和微环境界面（由地下水位波动引起）对地下过程的影响；(3)完善和扩展地下研究新技术的应用。该研究将在美国国家科学基金会的弗吉尼亚海岸保护区长期生态研究（LTER）站点的Hog岛的增加端，沿着65、35、25和5岁的社区建立样带进行。氮修正和未修正样地将用于测试氮有效性对地下过程的影响。将在处理区和对照区测量根系产量、根系分解、凋落物氮固定率、矿化率以及根系和土壤氮含量。凋落物袋移栽的目的是考察外部氮供给对凋落物质量的控制程度。所有过程都将根据微环境条件和沿样带和垂直土壤剖面的演代年龄进行评估。微型电子管在堰洲岛生态系统中的应用也将进行试验。该项目的结果将对养分动态治理和营养贫乏生态系统中植物群落组成的基本生态解决方案具有重要意义。此外，这项工作应产生见解，以协助更好地管理堰洲岛和海滨，在这些地区，保护、娱乐和商业发展的利益经常发生冲突。首席研究员是合格的，并且机构设施足以完成这项任务。将这个新项目与正在进行的弗吉尼亚海岸保护区LTER项目的研究计划相结合，将使这两方面的努力都取得更大的成效。