Collaborative Research: Sources and Fates of Ecosystem Nutrients Across the Hawaiian Islands

合作研究：夏威夷群岛生态系统养分的来源和归宿

• 批准号: 9816637
• 负责人: Barry Huebert
• 金额: $ 17.91万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-15 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9816637&HistoricalAwards=false
• 关键词: Collaborative; Research; Sources; Fates; Ecosystem

This project is a collaboration between the University of California, Santa Barbara, the University of Hawaii, and Cornell University. It was submitted to the Environmental Geochemistry and Biogeochemistry Program (EGB) and supported by the Atmospheric Chemistry, Petrology and Geochemistry, and Hydrologic Sciences Programs. The interdisciplinary team includes an ecosystem ecologist, a pedologist, an atmospheric chemist, and an isotope geochemist. The objective is to evaluate the sources and fates of elements deposited to Hawaiian ecosystems. Well characterized gradients in substrate age and precipitation will be utilized. Preliminary analyses of certain of these gradients suggest that atmospherically derived elements are crucial to the functioning of both older and wetter systems. This project will: (1) determine rates of atmospheric deposition of elements by wet, dry, and cloudwater deposition; (2) use elements in the lanthanide series, particularly the europium anomaly and neodymium isotopes, to trace the integrated contribution of continental dust to pools of more immobile elements; (3) determine the mineralogy, element pools, and weathering status of soils in all sites, and measure mineralogic indicators of dust inputs from continental sources; (4) analyze directly the cumulative contribution of atmospheric versus weathering sources to plant and soil strontium pools in all sites, and evaluate the sources of that strontium; and (5) integrate these measurements to estimate the contribution of atmospheric inputs to the pools and availability of all major elements, as these vary with substrate age and climate. Atmospheric wet, dry, and cloud deposition will be directly monitored at two sites representing the end members of the Hawaiian physical climate system. Deposition of mineral aerosols derived from Asia will be inferred by measuring the concentration of unique materials such as quartz in soils and the concentration of continentally derived trace element patterns (rare earth elements and Th, Hf) and neodymium isotopes. Further, the relationship between Nd and P will be explored to determine whether it is possible to use Nd isotopes as an indicator of mineral aerosol contributions of P to Hawaiian ecosystems. Measurements of soils will be used to determine patterns of mineralogy and element pools in space and time; because the sites are arrayed on well defined gradients, these can be used to calculate weathering inputs. Strontium isotope measurements will make use of the difference in isotopic ratio between the marine source of most atmospheric deposition and the rock source of weathering; both of these are well defined and consistent in the Hawaiian system. Measurements of quartz and trace elements will allow an estimate of Sr input from highly radiogenic continental sources.

该项目是加州大学圣巴巴拉分校、夏威夷大学和康奈尔大学之间的合作项目。它已提交给环境地球化学和生物地球化学计划（EGB），并得到大气化学、岩石学和地球化学以及水文科学计划的支持。该跨学科团队包括一名生态系统生态学家、一名土壤学家、一名大气化学家和一名同位素地球化学家。目的是评估沉积到夏威夷生态系统的元素的来源和归宿。将利用基质年龄和降水的充分表征的梯度。对某些梯度的初步分析表明，大气衍生的元素对于较旧和较湿润系统的功能至关重要。该项目将：（1）确定湿、干和云水沉降元素的大气沉降率； (2) 利用镧系元素，特别是铕异常和钕同位素，追踪大陆尘埃对更多固定元素库的综合贡献； (3) 确定所有场地土壤的矿物学、元素库和风化状况，并测量陆源粉尘输入的矿物学指标； (4) 直接分析大气与风化源对所有地点植物和土壤锶库的累积贡献，并评估该锶的来源； (5) 整合这些测量结果来估计大气输入对库的贡献以及所有主要元素的可用性，因为这些随着基质年龄和气候的变化而变化。大气湿、干和云沉降将在代表夏威夷物理气候系统最终成员的两个地点进行直接监测。来自亚洲的矿物气溶胶的沉积将通过测量土壤中石英等独特物质的浓度以及源自大陆的微量元素模式（稀土元素和钍、铪）和钕同位素的浓度来推断。此外，还将探索 Nd 和 P 之间的关系，以确定是否可以使用 Nd 同位素作为 P 对夏威夷生态系统的矿物气溶胶贡献的指标。土壤测量将用于确定矿物学和元素库在空间和时间上的模式；由于这些地点按照明确的梯度排列，因此可以使用它们来计算风化输入。锶同位素测量将利用大部分大气沉积的海洋来源与风化的岩石来源之间同位素比率的差异；这两者在夏威夷系统中都有明确的定义和一致。石英和微量元素的测量将能够估计来自高放射性大陆源的 Sr 输入。