Chromatographic separation and degradation of dissolved and particulate organic matter in permeable shelf sediment

可渗透陆架沉积物中溶解和颗粒有机物的色层分离和降解本项目将研究沙质沉积物在碳循环中的作用。砂质沉积物覆盖了约三分之一的大陆架，但对其研究还不够深入。就像沙子过滤器一样，当海水通过时，海洋沙子分离并捕获溶解的颗粒物质。这些过程会影响沉积物中的有机质循环。由于较小的颗粒比较大的颗粒更容易通过孔隙空间，它们会移动到海床更深的地方。这导致了颗粒物按大小分离。同样，氧和溶解化学物质随深度的变化也会改变沉积物颗粒的表面特性。基于这些表面特征，具有不同性质的分子被分离。沿海海洋中有机碳、溶解的营养物质和污染物的命运与沉积物的吸收、沉积物中的物理和微生物过程以及释放有关。因此，重要的是要了解控制海底物质运输和积累的过程。该项目将研究通过海砂输送的颗粒物和溶解有机物的分离。它将提供对理解海底碳和营养物质循环至关重要的信息。从事这个项目的研究生和本科生将接受有关海洋沉积物功能和最新方法的培训，这些方法可以帮助解决紧迫的环境问题。这项研究的主要目的是：1)通过对硅酸盐和碳酸盐砂层沉积岩心的分析，论证和量化陆架沉积物中有机质的色谱分离；2)表征和量化溶解和颗粒有机质的分离过程，并确定控制这种分离的关键因素；3)量化有机质色谱分离对这些砂体中沉积耗氧和溶解无机碳产生的影响。研究人员将检验这一假设，即在两种沙子中都会发生颗粒和溶质的色谱分离，但受影响的物质和分离的有效性不同。生物砂岩的粒内渗透性可以通过排阻层析效应加强碳酸盐岩砂的分离。分离过程预计将通过在特定沉淀层中浓缩可降解物质来增强分解活动。将结合实地和实验室研究来处理研究目标，其中包括示踪剂实验和分析实地取样的砂岩芯中溶解和颗粒有机物的分布。将测量氧气消耗和溶解无机碳产生，以揭示这一过程与沉积退化过程的相关性。海洋沙中颗粒和溶质的色层分离演示将填补我们对控制有机物、营养物质和污染物命运的化学过程的理解的空白。该项目将为研究生和本科生提供研究培训机会。这项研究的结果将有助于改进可用于预测全球环境变化的全球元素循环的模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Chromatographic separation and degradation of dissolved and particulate organic matter in permeable shelf sedimentThis project will study the role of sandy sediments in the carbon cycle. Sandy sediments cover about one-third of the continental shelf but are not well studied. Like a sand filter, marine sands separate and trap dissolved and particulate materials as seawater moves through. These processes influence organic matter cycling in sediments. Because smaller particles travel more easily through the pore space than larger ones, they move deeper into the seabed. This causes a separation of particulate matter by size. Likewise, changes in oxygen and dissolved chemicals with depth alter the surface properties of the sediment grains. Molecules with different properties are separated based on these surface characteristics. The fates of organic carbon, dissolved nutrients and pollutants in the coastal ocean are linked to uptake by sediments, physical and microbial processes within sediments, and release. Thus, it is important to understand the processes that control the transport and accumulation of materials in the seabed. This project will study the separation of particulate and dissolved organic matter transported through marine sands. It will provide information critical for understanding the cycling of carbon and nutrients at the seafloor. Graduate and undergraduate students working on this project will receive training in marine sediment functions and state-of-the-art methods that can help solve pressing environmental issues. The main objectives of this research are to: 1) demonstrate and quantify the chromatographic separation of organic matter in shelf sediments through the analysis of sediment cores from silicate and carbonate sand beds, 2) characterize and quantify the separation process of dissolved and particulate organic matter and identify key factors controlling this separation in the sands, and 3) quantify the influence of organic matter chromatographic separation on sedimentary oxygen consumption and dissolved inorganic carbon production in these sands. The researchers will test the hypothesis that chromatographic separation of particles and solutes takes place in both sand types but differs with respect to the substances affected and the effectiveness of the separation. Intra-grain permeability of biogenic sands can enhance separation in carbonate sands through exclusion chromatography effects. The separation process is expected to enhance decomposition activities through the concentration of degradable materials in specific sediment layers. The research objectives will be addressed with a combination of field and laboratory studies that include tracer experiments and the analysis of dissolved and particulate organic matter distribution in sand sediment cores sampled in the field. Oxygen consumption and dissolved inorganic carbon production will be measured to reveal the relevance of this process for the sedimentary degradation process. The demonstration of chromatographic separation of particles and solutes in marine sands will close a gap in our understanding of the chemical processes that govern the fate of organic matter, nutrients, and pollutants. This project will provide research training opportunities for graduate and undergraduate students. Results from this study will help improve models of the global cycles of elements that can be used for predicting global environmental change.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.