Calcium isotopic response to disturbance at Hubbard Brook: acidification, deforestation, and recovery

哈伯德布鲁克干扰的钙同位素反应：酸化、森林砍伐和恢复

• 批准号: 1324911
• 负责人: Andrew Kurtz
• 金额: $ 17.3万
• 依托单位: Trustees of Boston University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-15 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1324911&HistoricalAwards=false
• 关键词: Calcium; isotopic; response; disturbance; Hubbard

This study evaluates changes in Calcium (Ca) cycling at the Hubbard Brook Experimental Forest in New Hampshire based on measurements of Ca stable isotope ratios on a unique sample archive dating to as early as 1963. Like other Northeast U.S. forests, the Ca cycle was significantly perturbed by acid deposition beginning in the early 1950's resulting in increased Ca loss from bio-available soil pools and detrimental effects on forest growth. Additionally, several of the first order watersheds at HBEF have been experimentally logged allowing examination of the relationship between harvesting, Ca cycling and forest ecology. Research will address the following questions: How do the Ca isotope ratios of streamwater and soil change in response to disturbances including acidification and deforestation? What can such data tell us about the mechanisms of Ca loss from forest ecosystems and changes in Ca cycling resulting from disturbance? An isotope-tracer box model indicates that soil and streamwater Ca isotopes reflect the relative magnitudes of important fluxes in the forest Ca cycle (external supply, plant uptake, and recycling to soil), leading to a series of testable hypotheses related to the ecosystem-level response to these perturbations. The main hypothesis is that forest growth will take up Ca, limiting it's input to streamwater, while deforestation will increase streamwater Ca as runoff from soil. To address questions and hypotheses, Ca isotope ratios and elemental concentrations will be determined on a carefully selected group of archived soil parent material, precipitation, streamwater, soil, and vegetation samples.Ca biogeochemistry has important implications for forest sustainability, both in the NE US, Northern Europe, and China. Ca isotopes, like other tracers of Ca cycling, has the potential to resolve some of the uncertainties in the sources of Ca loss from forests that are not apparent from mass balance studies alone. This information is important beyond biogeochemical research, with implications for forest management and regionally important agribusiness, such as maple syrup production. This project will primarily support a graduate student in Boston University's new Terrestrial Biogeosciences PhD program. The graduate student and the PI will create modules for use by a future year's cohort of GLACIER graduate students that introduce middle school students to New England biogeochemistry, acid rain, and forest sustainability. The results of this project will further be communicated to the about 300 students at Boston University and Tufts that the PI teaches annually.

这项研究评估了新罕布什尔州哈伯德布鲁克实验森林的钙（CA）自行车的变化，基于对CA稳定的同位素比率的测量，该比率最早可追溯到1963年。与其他东北森林一样，CA周期与1950年代初期的酸造成的酸度造成了众多的生长，从而增加了Bio-avail的生长。此外，HBEF的一些一级流域已经进行了实验记录，以检查收获，CA骑自行车和森林生态学之间的关系。 研究将解决以下问题：溪流水和土壤的CA同位素比如何响应包括酸化和森林砍伐的干扰？这样的数据可以告诉我们有关森林生态系统中CA损失的机制以及因扰动而导致的CA自行车变化的机制？同位素跟踪盒模型表明，土壤和流水CA同位素反映了森林CA周期中重要通量的相对大小（外部供应，植物吸收和对土壤的回收），从而导致一系列与对这些局势的生态系统级别响应有关的可检验的假设。 主要假设是森林的增长将占用CA，限制了其对流水的投入，而森林砍伐将增加流水CA作为土壤径流。 为了解决问题和假设，CA同位素比率和元素浓度将在精心选择的一组存档的土壤母体材料，降水，溪流，土壤和植被样品上确定。与CA骑自行车的其他示踪剂一样，CA同位素具有解决森林中CA损失造成的某些不确定性的潜力，而森林造成的森林造成了一些不确定性，而这些森林仅从群众平衡研究中就明显看出。除了生物地球化学研究之外，该信息对森林管理和区域重要的农业综合企业（例如枫糖浆生产）具有重要意义。 该项目将主要支持波士顿大学新的地面生物科学博士学位课程的研究生。研究生和PI将创建模块，以供未来一年的冰川研究生组成，这些冰川研究生将中学生介绍新英格兰生物地球化学，酸雨和森林可持续性。该项目的结果将进一步传达给波士顿大学的大约300名学生和PI每年教授的簇。