CAREER: Land Use and Environmental Controls on Soil Carbon in Human-Dominated Tropical Landscapes

职业：人类主导的热带景观中土壤碳的土地利用和环境控制

• 批准号: 1349952
• 负责人: Erika Marin-Spiotta
• 金额: $ 42.5万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-15 至 2020-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1349952&HistoricalAwards=false
• 关键词: CAREER; Land; Use; Environmental; Controls

One of the major uncertainties in predicting changes in earth's climate is how one of the world's largest terrestrial carbon reservoirs, soils, responds to environmental change. Changes in land use and land cover, such as deforestation for agriculture or pasture use, or forest regrowth after agricultural abandonment, affect the exchange of carbon between soils and the atmosphere, with implications for climate and soil fertility. Past human activities can influence the quantity and dynamics of carbon in soils. Despite this, and the fact that an increasing proportion of the Earth's surface is covered by human-modified landscapes, few regional-scale assessments of soil carbon incorporate historical land use. This project will focus on how historical and environmental factors affect how much carbon is stored in tropical soils and its vulnerability to disturbance. Tropical regions are experiencing dynamic changes in land cover and increasing human population growth, yet our understanding of how tropical soils respond to global change is limited to few soil environments which are not representative of the global tropics. The proposed field research will take place in the U.S. Caribbean island of Puerto Rico. Puerto Rico is a model system to study interactions between environmental and human factors in the tropics because it represents a diversity of climatic regions, ecosystem and soil types. The proposed educational activities will provide students with interdisciplinary research and career skills training and field experience and will increase participation of underrepresented communities in geography and the geosciences, in particular women and Hispanic students. Collaborations with agency scientists will facilitate broad dissemination of research results to managers and policymakers. This project aims to measure legacy effects of past human activities on tropical soil carbon dynamics by taking advantage of an extraordinary natural laboratory in Puerto Rico with a rich diversity of geologic substrates, precipitation gradients, and well-documented land-use history. The project will quantify carbon storage (amount and turnover) under different land uses across environmental gradients with a long history of human management through the collection of new data and integration of archived data to increase the geographic representation of tropical soil environments. The project will evaluate the magnitude and persistence of historical land use legacy effects on soil carbon with time across different soil types using carbon isotope depth profiles and field chronosequences. Improved mechanistic understanding of the effects of soil type, climate and land use on soil organic matter retention to will be accomplished through physical fractionation approaches that investigate the sensitivity of different soil carbon pools to disturbance and the use of natural abundance radiocarbon isotopes to measure carbon storage effectiveness. The research and educational activities will provide students with training in field, lab, geospatial and data analysis skills. The integration of research and educational activities will create new opportunities for collaborations between social and physical scientists, especially through the development of a mixed-methods field course focused on environmental challenges in human-dominated tropical landscapes.

预测地球气候变化的主要不确定性之一是世界上最大的陆地碳储层之一，土壤，对环境变化做出反应。土地使用和土地覆盖的变化，例如农业或牧场使用的森林砍伐，或农业遗弃后的森林再生，会影响土壤与大气之间的碳交换，这对气候和土壤肥力的影响。过去的人类活动会影响土壤中碳的数量和动态。尽管如此，地球表面越来越多地被人类改造的景观所涵盖的事实，对土壤碳的区域评估很少有历史土地使用。该项目将重点介绍历史和环境因素如何影响热带土壤中的碳量及其易受干扰的脆弱性。热带地区正在经历土地覆盖的动态变化和人口增长的增加，但是我们对热带土壤如何响应全球变化的理解仅限于几乎没有代表全球热带地区的土壤环境。拟议的实地研究将在美国加勒比岛的波多黎各岛进行。波多黎各是一个模型系统，用于研究热带环境和人为因素之间的相互作用，因为它代表了气候区域，生态系统和土壤类型的多样性。拟议的教育活动将为学生提供跨学科的研究和职业技能培训和现场经验，并将增加代表性不足的社区参与地理和地理科学，尤其是妇女和西班牙裔学生。与代理科学家的合作将促进向经理和政策制定者广泛传播研究结果。该项目旨在通过利用波多黎各的非凡天然实验室来衡量过去人类活动对热带土壤碳动态的遗产，并具有丰富的地质基材，降水梯度和有据可查的土地利用历史。该项目将通过收集新数据并集成存档数据，以增加热带土壤环境的地理表示，从而在不同的环境梯度中量化碳存储（数量和营业额）。该项目将使用碳同位素深度剖面和田间变形值评估土壤碳的历史使用遗产对土壤碳的大小和持久性。对土壤类型，气候和土地利用对土壤有机物保留的影响的改进的理解将通过物理分馏方法来实现，这些方法研究了不同土壤碳池对干扰和使用自然丰度放射性碳同位素的敏感性，以测量碳储存效率。研究和教育活动将为学生提供现场，实验室，地理空间和数据分析技能的培训。研究和教育活动的整合将为社会科学家和物理科学家之间的合作创造新的机会，尤其是通过开发混合方法的野外课程，该课程着重于人类主导的热带景观中的环境挑战。