Collaborative Research: Episodic, ENSO-Orchestrated Carbon Sequestration in Amazonian River Basins by Erosion-Sedimentation Processes

0403722 Montgomery这个跨学科小组的提案提出了一个三步过程，可以代表亚马逊前陆盆地的一个主要碳汇。作为假说，该建议认为：1）大规模拉尼娜风暴期间安第斯山脉的山坡破坏和河道迁移动员了大量新鲜有机质和低有机碳含量的沉积物：2）在河流中，矿物表面通过吸附获得正常的有机碳负荷，因为它们迅速从山地源盆地转移到邻近的前陆沉积中心; 3）沉积沉积物将“新鲜“碳保存在有机-矿物复合体中，并深埋在与生物圈和大气交换的潜力很小的点坝和“裂缝-扇展”沉积物中。项目说明（C.1.2）中的计算表明，这一过程每次可在亚马逊前陆固碳约3亿吨。当外推到全球其他潮湿的热带地区时，这些估计值相当于拉尼娜期间典型观测到的年均“缺失碳汇”或大气CO2异常的50 - 100%。为了探索这些假设，提议者将研究1）极端事件期间沉积物移动、运输和河流沉积物沉积的速率和机制，2）有机碳与沉积物的关系; 3）有机碳通过吸附和深埋过程从快速（5年）周转池向缓慢（50年）周转池转移。我们将综合利用地理信息系统对卫星图像的分析，绘制与个别大风暴有关的变化（山坡崩塌和河流迁移）;对沉积物迁移过程进行实地调查;对存档和新收集的样本进行实验室分析，以确定有机碳的浓度、来源和周转时间;沉积物特性;以及迁移/沉积时间和速率（地质年代学）。拟议的项目是一个合作，多学科，多国的研究工作，建立在一个记录之前和目前的NSF资助的结果十年尺度的沉积物通量和有机碳动态亚马逊流域内。与华盛顿大学的科学家进行的沉积通量、地质年代学、地球化学和过程制图（GIS）研究密切配合，斯特劳德水研究中心和加州戴维斯大学的科学家将调查这些地貌过程中动员的有机碳的数量、来源和封存。此外，该项目还得益于与法国发展研究所的密切合作，我们将与该研究所在安第斯山脉以及玻利维亚和秘鲁的前陆盆地进行旱季和雨季的实地考察。其他合作是与国立农业大学拉莫利纳（UNALM）和加州圣巴拉巴拉大学。这些持续的国际合作为目前研究极端风暴事件输送和沉积的碳的提议提供了相当大的科学和后勤优势，并节省了成本。如果这项研究工作证实了主要假设，这种大陆尺度的，气候驱动的，侵蚀-沉积过程将被证明是代表大量的，以前未被认识到的全球意义的天然碳汇。此外，这些过程可能会导致类似数量的碳通过侵蚀加速沉积作用。此外，这项研究有利于任何对沉积物和土壤中有机碳保存的地球化学过程感兴趣的人，或者在极端ENSO编排洪水期间滑坡，沉积物运输，通道-洪泛区相互作用和沉积盆地动态的时间/速率/机制。地貌学、地球化学和有机地球化学学科之间的强有力的桥梁，通过提供新的视角，促进新的地球化学和GIS技术的发展，对整个地球科学产生了更广泛的影响。加强与国际放射学研究所的合作，有助于建立富有成效和引人注目的国际跨学科科学伙伴关系。例如，我们以前与IRD的合作研究导致了对土著居民河岸食物来源中汞污染动态的新理解。PI有公共宣传的记录，这个项目将产生对教育工作者和研究人员有用的数据产品，包括我们自己的教学和对科学家和普通观众的公开演讲。此外，这将为美国和南美洲的许多本科生和一些研究生提供宝贵的研究经验，包括为这些学生在会议上发表和展示结果提供资金。“VMATIS PFRM 1036 04/20/2004 14：26：40：33 1

0403722MontgomeryThis interdisciplinary group proposal addresses a three-step process that could represent a major carbon sink in Amazonian foreland basins. Stated as hypotheses, the proposal suggests: 1) extensiveAndean hillslope failure and channel migration during large La Nina associated storms mobilizes vast quantities of fresh organic matter and sediment with low organic carbon (OC) content ; 2) within theriver, mineral surfaces acquire normal OC loadings via sorption as they are rapidly evacuated from the mountainous source basins to adjacent foreland depocenters; and 3) deposited sediments preserve "fresh"carbon within organo-mineral complexes and by deep burial in point bars and "crevasse-splay" deposits that have little potential for exchange with the biosphere and atmosphere. Calculations presented in theProject Description (C.1.2) suggest that this process could sequester ~ 300 Mtonnes of carbon per event in the Amazonian foreland. When extrapolated globally to other humid tropical regions, these estimates areequivalent to 50-100% of the average annual "missing carbon sink" or 50-100% of atmospheric CO2 anomalies typically observed during La Nina.To explore these hypothesis, proposers will study 1) the rates and mechanics of sediment mobilization, transport, and deposition of river sediment during extreme events, 2) the associations oforganic carbon with sediments at erosional and depositional sites, and 3) the transfer of OC from rapid (5 y) to slower (50 y) turnover pools, via sorption and deep burial processes. We will employ a combination of GIS analysis of satellite images to map changes associated with individual large storms(hillslope failures and river migration); field surveys of sediment transport processes; and laboratory analysis of archived and newly collected samples to determine organic carbon concentrations, sources andturnover times; sediment characteristics; and transport/deposition timing and rates (geochronology). The proposed project is a collaborative, multi-disciplinary, multi-national research effort that builds upon a record of prior and current NSF-funded results of decadal-scale sediment fluxes and organiccarbon dynamics within river basins of the Amazon. In close coordination with sediment-flux, geochronological, geochemical, and process-mapping (GIS) studies conducted by scientists from Univ. of Washington, scientists at Stroud Water Research Center and Univ. of California Davis will investigate thequantities, sources, and sequestration of organic carbon mobilized during by these geomorphological processes. In addition, this project benefits from a close working collaboration with the French Institut deRecherche pour le Developpement (IRD), with whom we will conduct fieldwork in the Andes and foreland basins of Bolivia and Peru during both the dry and wet seasons. Additional collaborations arewith the Univ. Nacional Agraria La Molina (UNALM) and the Univ. of California Santa Barabara. These continuing international collaborations offer considerable scientific and logistical advantages and costsavings for this current proposal to study the carbon transported and deposited by extreme storm events. If this research effort substantiates the primary hypothesis, such continental-scale, climate-driven,erosion-sedimentation processes will be demonstrated to represent substantial, previously unrecognized natural carbon sinks of global significance. Furthermore, these processes could potentially result in thesequestration of similar quantities of carbon by anthropogenically accelerated erosion-sedimentation. Additionally, this research benefits anyone interested in the geochemical processes of organic carbonpreservation in sediment and soils or the timing/rates/mechanics of landsliding, sediment transport, channel-floodplain interaction, and sedimentary basin dynamics during extreme, ENSO-orchestratedfloods. The strong bridging between the disciplines of geomorphology, biogeochemistry and organic geochemistry has broader impacts on earth science as a whole, by offering new perspectives that will facilitate the development of new geochemical and GIS techniques. Enhanced collaboration with IRDsupports a productive and visible international, interdisciplinary scientific partnership. For example, our previous collaborative research with IRD resulted in new understandings of mercury contamination dynamics within riparian food sources to indigenous human populations. The PIs have a record of publicoutreach, and this project will generate data products useful to educators and researchers, including our own teaching and public presentations to both scientists and general audiences. Furthermore, this will provide valuable research experience to many undergraduate and some graduate students in the USA and South America, including funds for these students to publish and present results at meetings." VMATHIS PFRM1036 04/20/2004 14:26:40:33 1