COLLABORATIVE RESEARCH: Anthropogenic Impacts on Carbon Cycling in the Sacramento-San Joaquin River Delta- Changes in Source, Nature and Age of Organic Carbon

合作研究：人为对萨克拉门托-圣华金河三角洲碳循环的影响——有机碳的来源、性质和年龄的变化

• 批准号: 0454741
• 负责人: Stuart Wakeham
• 金额: --
• 依托单位: Skidaway Institute of Oceanography
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0454741&HistoricalAwards=false
• 关键词: COLLABORATIVE; RESEARCH; Anthropogenic; Impacts; Carbon

Intellectual Merit Organic carbon is the source of the energy that fuels biological production at the base of the foodweb. In aquatic ecosystems, organic matter derives from broken-up pieces of plants, algae and phytoplankton in the water and soil. Some sources of organic matter are imported by rivers from upland sources including soils and plant detritus (terrigenous sources), which tends to be lower in quality and less useful to aquatic organisms as a food source. Other sources of organic matter are produced within marshes, lakes and other aquatic systems and tend to be of higher nutritional value. In recent decades, human activities have altered aquatic ecosystems by changing freshwater flow, introducing exotic or non-native species, contributing to declining water quality through nutrient enrichment, and by the construction of dams. These activities have altered the amount, sources, and quality of carbon supplied to aquatic ecosystems. This project will use the Sacramento-San Joaquin River Delta, CA (referred to as the "Delta" hereafter) as a model system for understanding how human modifications influence the abundance, sources and age of carbon in sediments representing the past 100-200 years. The project will examine the organic carbon composition of sediments collected from sites representing key sub-environments of the Delta using "biomarkers", naturally-occurring chemical tracers that allow us to identify the sources of organic carbon. The objectives of this study will be to use these "biomarkers" to: (1) identify the sources of the aquatic and terrigenous components of sedimentary organic matter (SOM) currently being deposited within sub-habitats of the Delta; (2) determine how anthropogenic activities have altered the composition of organic matter delivered to the Delta using biomarker distributions in sediment cores, and (3) use the natural abundance of radiocarbon to determine the average age of organic carbon (TOC) and source-specific biomarkers to apportion organic matter sources and determine the radiocarbon ages of aquatic and terrigenous components of the SOM. Broader ImpactsThis project will address basic questions related to human impacts on carbon quality in a representative highly modified ecosystem-the Sacramento-San Joaquin River Delta and will test fundamental hypotheses about the determinants of community structure and degradation of deltaic habitats. Deltaic habitats provide habitat for fishes and invertebrates that feed a large proportion of the world's human population and sustaining these dynamic ecosystems is of clear scientific, social and economic significance. To the best of our knowledge, our study will be the first to apply a multi-biomarker approach to questions of environmental change in deltaic environments and assess these changes within the context of potential restoration issues. The broader impacts of the proposed work also include a unique training opportunities for students to conduct interdisciplinary research that addresses questions of fundamental importance to ecosystem science at the interface between basic and applied research. This project will also engage under-represented groups and students at various stages in their training (high school, undergraduate and graduate) in aquatic sciences research through specialized programs at the three institutions involved in this study.

智力优点有机碳是在FoodWeb底部燃料生物生产的能量的来源。在水生生态系统中，有机物源自水和土壤中的植物，藻类和浮游植物。有机物的某些来源是由河流从高地来源的河流进口的，包括土壤和植物碎屑（地源），这些河流的质量较低，对水生生物作为食物来源的质量较低，对水生生物有用。有机物的其他来源是在沼泽，湖泊和其他水生系统中产生的，并且往往具有更高的营养价值。近几十年来，人类的活动通过改变淡水流动，引入异国情调或非本地物种，改变了水生生态系统，通过营养富集和建造大坝有助于水质下降。这些活动改变了提供给水生生态系统的碳的数量，来源和质量。该项目将使用加利福尼亚州的萨克拉曼多 - 桑·华金河三角洲（以下称为“三角洲”）作为一种模型系统，用于了解人类修饰如何影响代表过去100 - 100年的沉积物中的丰度，碳的来源和年龄。该项目将使用“生物标志物”，自然存在的化学示踪剂，从代表三角洲的关键亚环境中收集的沉积物的有机碳组成，使我们能够识别有机碳的来源。这项研究的目的是将这些“生物标志物”用于：（1）确定当前存放在三角洲亚班迪塔特人中的沉积有机物（SOM）的水生和田格成分的来源； (2) determine how anthropogenic activities have altered the composition of organic matter delivered to the Delta using biomarker distributions in sediment cores, and (3) use the natural abundance of radiocarbon to determine the average age of organic carbon (TOC) and source-specific biomarkers to apportion organic matter sources and determine the radiocarbon ages of aquatic and terrigenous components of the SOM.在代表性的高度修改的生态系统 - 萨克拉曼多 - 山华金河三角洲，这将解决与人类对碳质量的影响有关的基本问题，并将检验有关社区结构和降解三角洲栖息地的降解的基本假设。三角洲栖息地为鱼类和无脊椎动物提供了栖息地，这些栖息地养活了世界人口中很大一部分，并维持这些动态的生态系统具有明显的科学，社会和经济意义。据我们所知，我们的研究将是第一个将多生物标志物方法应用于三角洲环境中环境变化问题的问题，并在潜在的恢复问题的背景下评估这些变化。拟议工作的更广泛的影响还包括学生在基础研究和应用研究之间的界面上解决对生态系统科学的基本重要性的跨学科研究的独特培训机会。该项目还将通过本研究的三个机构的专业计划在水上科学研究中参与各个阶段（高中，本科和毕业生）的培训（高中，本科和研究生）的各个阶段的学生和学生。