Collaborative Research: Delivery and Burial of Particulate Organic Carbon (POC) on Ocean Margins Dominated by Small, Mountainous Rivers: the Role of Effective Discharge

我们将研究控制不同类型陆源颗粒有机碳（POC）通过美国西海岸山区小河流运输的基本因素，重点是乌姆普夸河、鳗鱼河和萨利纳斯河。此外，我们将探讨河流流量与邻近沿海海洋波浪/风能之间的一致性，作为控制陆源POC最终命运的关键因素（即广泛扩散和退化vs.局部积累和保存）。为了实现这些目标，将从所有三条河流和河漫滩沉积物中收集有代表性的悬浮颗粒物样本，以量化大范围排放的POC负荷的大小和组成。洪水过后对洪泛区和大陆边缘沉积物的事件响应采样将提供对短期碳埋藏模式的洞察。更长的沉积物档案也将在河流流域和沿海海洋中收集，以提供过去几千年最大事件的记录，并在气候变化和人类引起的流域变化的背景下调查POC埋藏的大小和组成的历史变化。我们将结合这些数据来研究与陆地-海洋连续体中不同类型碳的传递和埋藏相关的事件的强度和频率。我们的结果将与美国地质勘探局（USGS）测量站、美国国家海洋和大气管理局（NOAA）海洋浮标和美国国家气象局（NWS）气象站的数据集相结合，扩大到整个美国西海岸。这项工作更广泛的意义和重要性在于这样一个事实，即小的、多山的河流占全球向海洋输送颗粒物的50%，并主导着北美西海岸。然而，尽管它们具有全球和区域重要性，但对碳如何从高起伏盆地运输并埋在沿海边缘的定量了解尚缺乏。通过关注河流流量对输送和掩埋的影响，本研究将在水文学和海洋学之间建立统一的联系。通过我们的事件响应采样，我们将开发新的方法来吸收来自陆地和海洋实时监测站不断增加的信息流。最后，在不断变化的水文气候条件和土地利用实践下，流经流域的物质通量具有广泛的社会意义。沉积物和颗粒相关的有机污染物都是美国地表水中常见的污染物。因此，通过提供关于河流悬浮沉积物和碳负荷的新信息，并将知识扩展到罕见的高强度事件，我们将为研究区域内与污染相关的问题提供重要的启示。

We will investigate the fundamental factors controlling the transport of different types of land-derived particulate organic carbon (POC) by small, mountainous rivers on the US West Coast with an emphasis on the Umpqua, Eel and Salinas Rivers. Moreover, we will explore the coherence between river discharge and wave/wind energy in the adjacent coastal ocean as the key factor controlling the ultimate fate of land-derived POC (i.e., widespread dispersal & degradation vs. localized accumulation & preservation). To achieve these objectives, representative samples of suspended particulate matter will be collected from all three rivers and from floodplain deposits to quantify the magnitude and composition of the POC load over a wide range of discharges. Event-response sampling of sediments from both the floodplains and continental margins following floods will provide insight into short-term carbon burial patterns. Longer sediment archives will also be collected within the river basins and coastal ocean to provide a record of the largest events over the past several millennia and to investigate historical changes in the magnitude and composition of POC burial in the context of climatic changes and human-induced alterations of the watersheds. We will combine these data to investigate the magnitude and frequency of events associated with the delivery and burial of different types of carbon across the land-ocean continuum. Our results will be up-scaled to the entire US West Coast margin by integrating them with data sets from USGS gauging-stations, NOAA ocean-buoys and NWS meteorological stations. The broader significance and importance of the work resides in the fact that small, mountainous rivers account for 50% of global transport of particulates to the ocean and dominate the west coast of North America. However, in spite of their global and regional importance, a quantitative understanding of how carbon is transported from high-relief basins and buried on coastal margins is lacking. By focusing on how delivery and burial vary as a function of river discharge this research will forge a unifying link between hydrology and oceanography. Through our event-response sampling, we will develop novel approaches to assimilate the ever-increasing flow of information from real time monitoring stations on land and in the ocean. Lastly, the flux of material through river basins under changing hydroclimatic conditions and land-use practices has widespread societal relevance. Both sediment and particle-associated organic contaminants are common pollutants in US surface waters. Thus, by providing new information on river suspended-sediment and carbon loads, and extending knowledge to rare, high-magnitude events we will shed important light on pollutant-related issues within the study region.