Developing a Global Perspective on Dynamics of Riverine Transfer of Terrestrial Biospheric Carbon to the Ocean

发展陆地生物圈碳向海洋河流转移动态的全球视角

• 批准号: 0928582
• 负责人: Valier Galy
• 金额: $ 30.46万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-01 至 2013-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0928582&HistoricalAwards=false
• 关键词: Developing; Global; Perspective; Dynamics; Riverine

Over short timescales, small changes in the rate of exchange between large pools of "active" carbon such as soils and vegetation can significantly impact the size of the atmospheric CO2 reservoir. Therefore, to predict the ecological and biogeochemical consequences of the current atmospheric CO2 increase and concomitant global warming, we need to understand the natural processes of carbon exchange between these carbon reservoirs. A key aspect in this regard is the global-scale interaction between climate and the dynamics of terrestrial biospheric carbon cycling. In particular, we have only a very rudimentary understanding of the timescales over which carbon fixed by vascular plants on land is exported to the oceans - a crucial component of the carbon cycle. In this project, researchers at the Woods Hole Oceanographic Institution will begin to build a global database on the age of different terrestrial organic carbon (OC) constituents exported by rivers. The focus will be on terrestrial biospheric carbon exported within the particulate OC pool because it has a pivotal role in the global carbon cycle, is potentially the more sensitive to rapid perturbations such as climate change and anthropogenic activity, and leaves a legacy within continental margin sediment records that can be retrieved for paleoclimate reconstructions. The team will study the composition of terrestrial biospheric carbon discharged by rivers to the oceans by characterizing suspended sediments collected close to the terminus of the rivers, as well as deltaic deposits and inner shelf flood deposits. They will attempt to couple radiocarbon (14C) measurements at different levels - from bulk OC to specific molecules (biomarkers) - in order to constrain the age and relative proportion of the different constituents of the biospheric OC pool. They expect to derive a global picture of the dynamics of terrestrial biospheric OC export to the ocean by examining age characteristics of vascular plant-derived carbon discharged by a wide range of rivers that differ markedly in terms of drainage basin size, elevation, latitude, and materials flux. Specifically, they will (1) evaluate the robustness of the preliminary relationship observed between the age of riverine vascular plant-derived OC and the latitude of the river outlet, (2) more precisely define the nature of this relationship, (3) examine whether similar relationships holds for different components of the biospheric OC pool, and finally, (4) use these findings to explore the mechanisms controlling the age of the biospheric carbon discharged by rivers to the ocean at the global scale, and hence to derive insights into the interactions between OC cycling and regional and global climate. Broader impacts: This research initiative is fundamentally based on a collaborative approach that will utilize samples and knowledge shared by a large number of American, Chinese, and European colleagues who are involved in river studies all around the globe. The publications arising from this endeavor will reflect these collaborative partnerships. The project will provide a collaborative research, training and learning environment for a postdoctoral scientist at WHOI. Data emanating from the project will be contributed to a legacy database that is currently being compiled. The data will be shared with the community through publications, through a dedicated website, as well as by linking to other web-accessible community databases.

在短时间内，土壤和植被等大型“活性”碳池之间交换率的微小变化就会显着影响大气二氧化碳库的规模。因此，为了预测当前大气二氧化碳增加和随之而来的全球变暖的生态和生物地球化学后果，我们需要了解这些碳库之间碳交换的自然过程。这方面的一个关键方面是气候与陆地生物圈碳循环动态之间的全球范围相互作用。特别是，我们对陆地维管束植物固定的碳输出到海洋的时间尺度只有非常初步的了解——海洋是碳循环的重要组成部分。在该项目中，伍兹霍尔海洋研究所的研究人员将开始建立一个关于河流输出的不同陆地有机碳（OC）成分年龄的全球数据库。 重点将放在颗粒有机碳库中输出的陆地生物圈碳，因为它在全球碳循环中具有关键作用，可能对气候变化和人类活动等快速扰动更敏感，并在大陆边缘沉积物中留下遗产可以检索用于古气候重建的记录。 该团队将通过表征靠近河流终点处收集的悬浮沉积物以及三角洲沉积物和内陆架洪水沉积物来研究河流排放到海洋的陆地生物圈碳的组成。他们将尝试将不同水平的放射性碳 (14C) 测量结合起来——从大量 OC 到特定分子（生物标记物）——以限制生物圈 OC 池中不同成分的年龄和相对比例。 他们希望通过检查各种河流排放的维管植物来源的碳的年龄特征，得出陆地生物圈向海洋输出有机碳的动态的全球图景，这些河流在流域大小、海拔、纬度和气候方面存在显着差异。材料通量。具体来说，他们将（1）评估河流维管植物来源的 OC 年龄与河流出口纬度之间观察到的初步关系的稳健性，（2）更精确地定义这种关系的性质，（3）检查是否生物圈OC库的不同组成部分也存在类似的关系，最后，（4）利用这些发现探索控制全球范围内河流向海洋排放的生物圈碳年龄的机制，从而深入了解生物圈碳的年龄。 OC之间的相互作用自行车运动与区域和全球气候。更广泛的影响：这项研究计划从根本上建立在协作方法的基础上，该方法将利用大量参与全球河流研究的美国、中国和欧洲同事共享的样本和知识。这一努力产生的出版物将反映这些合作伙伴关系。该项目将为 WHOI 的博士后科学家提供合作研究、培训和学习环境。该项目产生的数据将被贡献到当前正在编译的遗留数据库中。这些数据将通过出版物、专门网站以及链接到其他可通过网络访问的社区数据库与社区共享。