Collaborative Research: A dual-dye approach to measuring in situ light fields: development and preliminary field testing

由于光的存在，光场的测量和模型一直是人们关注的焦点。在水生生态系统中天然有机物的初级和次级生产以及光化学反应中的重要作用。 然而，这些研究依赖于欧拉测量而不是拉格朗日测量，并且没有考虑电流和其他物理过程对光粒子相互作用的影响。 来自明尼苏达大学、杜卢斯大学和Old自治领大学的研究人员计划开发和测试光积分器，该光积分器将通过在淡水和海水中以已知比例部署两种荧光染料来测量拉格朗日意义上的水包裹的曝光/光历史。 待使用的染料之一将是光敏的，并且在光合有效辐射（荧光素或氨基-G）的存在下衰减，而另一种将是光稳定的（罗丹明-WT）。 将进行实验室实验，以表征淡水、微咸水和盐水中的染料，以（1）确定荧光素和罗丹明-WT在阳光下衰减的波长;（2）评估染料是否因生物过程和/或染料吸附到颗粒上而损失;（3）确定温度、pH值、离子强度和光剂量/强度的影响;（4）确定双染料法描述水柱混合层光场的可行性。 该项目的结果将是开发一种潜在的变革性新技术，用于量化影响光敏生物和化学物种的水柱光历史。利用海洋学和湖沼学工具箱中的双染料对，我们可以对光和初级生产、光抑制、CDOM光漂白和水生环境中人为化合物的光化学归宿之间的关系有更有预见性的了解。由北方明尼苏达州水研究和水管理社区成员参加的会议，并通过将创建的网站进行传播。 新的分析技术将被纳入高级化学课程。 明尼苏达大学杜卢斯（UMD）的一名研究生和一名本科生以及旧自治领大学的一名研究生将作为该项目的一部分得到支助和培训。 本科生也将参与这项研究，并将得到UMD夏季本科生研究计划（SURP）的支持。 高中毕业生和K-12科学教师将参与实验室工作

A lot of attention has been focused on light measurements and models of light fields because of light?s significant role in primary and secondary production and photochemical reactions of natural organic matter in aquatic ecosystems. However, these studies have relied upon Eulerian measurements rather than Lagrangian ones and have not taken into account the effect of currents and other physical processes on light-particle interactions. Researchers from the University of Minnesota, Duluth and Old Dominion University plan to develop and test light integrators that will measure the light exposure/light history of parcels of water in a Lagrangian sense by deploying two fluorescent dyes in a known ratio within freshwater and seawater. One of the dyes to be deployed will be light sensitive and decay in the presence of photosynthetically active radiation (fluorescein or amino-G) while the other one will be photostable (rhodamine-WT). Laboratory experiments will be carried out to characterize the dyes in fresh, brackish, and salt water to (1) establish the wavelengths that are responsible for fluorescein and rhodamine-WT decay in sunlight; (2) assess whether the dyes are subject to loss due to biological processes and/or adsorption of the dyes onto particles; (3) determine the effects of temperature, pH, ionic strength, and light dose/intensity; and (4) ascertain the feasibility of the dual dye method for describing the light field in the water column mixed layer. The result of this project will be the development of a potentially transformative new technique for quantifying the water-column light history that impacts light sensitive organisms and chemical species. With dual-dye pairs within the oceanographic and limnological tool box, we can develop a more predictive understanding of the relationships between light and primary production, photoinhibition, CDOM photobleaching and the photochemical fate of anthropogenic compounds in the aquatic environment.As regards broader impacts, results from the study would be presented to "Freshwater Folks", a meeting attended by members of the water research and water management community of Northern Minnesota and disseminated via a website that would be created. The new analytical technique would be included into advanced chemistry courses. One graduate and one undergraduate student from the University of Minnesota, Duluth (UMD) and one graduate student from Old Dominion University would be supported and trained as part of this project. Undergraduate students would also participate in the study and would be supported by the Summer Undergraduate Research Program (SURP) at UMD. High school seniors and K-12 science teachers would be involved in the laboratory work