Photodissolution of Sedimentary Organic Matter

海洋光化学领域以前的重点是溶解有机物和痕量金属。然而，最近的研究表明，海洋中的沉积物悬浮也受到阳光的影响，并有可能将其大部分颗粒有机碳溶解到溶解的有机相中。缅因州大学的一名研究人员将确定光解在路易斯安那州沿海地区的重要性，那里的河流颗粒很快就会沉积在浅水中。将检查颗粒的光学性质，以评估光子通量，并确定这种光溶解反应的量子产率。为了确定这一反应的重要性，将进行混浊近岸区域的模拟、光学结果的现场测试以及以前的光解标记的发展。除了颗粒的光学性质外，还将评估光解有机物的命运，包括光氧化反应和生物矿化反应。在更广泛的影响方面，这项研究将为颗粒有机物的光降解对密西西比河三角洲地区营养物质循环的影响提供新的见解。将根据K-12和社区一级的研究活动开展外联工作。作为学习的一部分，一名研究生和一名本科生将得到支持和培训。

ABSTRACTOCE-0623331The field of marine photochemistry has previously focused on dissolved organic matter and trace metals. However, recent studies have shown that sediment suspensions in the ocean are also affected by sunlight and have the potential to dissolve most of their particulate organic carbon to the dissolved organic phase. A researcher from the University of Maine will determine the importance of photodissolution in the coastal Louisiana area, where riverine particulates are quickly deposited in shallow waters. Optical properties of the particulates will be examined to assess the photon fluxes and to determine the quantum yields of this photodissolution reaction. To determine the importance of this reaction, modeling of the turbid nearshore regimes, field-tests of the optical results, and developments of the markers from previous photodissolutions will be carried out. In addition to the optical properties of the particulates, the fate of the photodissolved organic matter will be assessed, addressing both photo-oxidation and biological mineralization reactions. In terms of the broader impacts, this research will provide new insights into the impact of photodegradation of particulate organic matter on the cycling of nutrients in the deltaic region of the Mississippi River. Outreach efforts based on the research activities at the K-12 and community level will be carried out. One graduate student and one undergraduate student will be supported and trained as part of the study.