UNS: Spatial and Temporal Variability in CDOM by Optical Remote Sensing: Effects on Water Quality, Water Treatment, and Aquatic Ecosystem Properties

1510332

Hozalski

Dissolved organic matter occurs in all natural waters, and chromophoric dissolved organic matter is the most abundant fraction in many natural waters, especially in forested watersheds with wetlands. Dissolved organic matter and chromophoric dissolved organic matter strongly affects water quality through its ability to mobilize metals and hydrophobic chemicals, serve as a source of reactive photochemical intermediates, and control many aquatic ecosystem processes. Dissolved organic matter has negative effects on production of safe drinking water resulting from the formation is disinfection by-products in treatment plants. This project will dramatically improve the state of knowledge on chromophoric dissolved organic matter by refining procedures to retrieve chromophoric dissolved organic matter from satellite imagery, using the new (Landsat 8) and forthcoming satellites.

This project will enable the first census-level assessment of chromophoric dissolved organic matter levels across a large region comprising three major ecoregions of the Upper Midwest. The goals of this multidisciplinary project are to leverage the teams optical remote sensing capabilities with modern field and lab techniques to: (i) dramatically improve understanding of the distribution, time trends, and environmental factors affecting Dissolved organic matter and chromophoric dissolved organic matter levels in surface waters and (ii) advance understanding of their source-dependent characteristics relevant to their potential to cause water treatment problems. With specific objectives of the proposed to: (1) develop robust equations to retrieve chromophoric dissolved organic matter data from satellite imagery and use the results to develop census-level chromophoric dissolved organic matter data for all lakes in three Upper Midwest ecoregions; (2) investigate long-term trends in lake chromophoric dissolved organic matter in the northern US using historical Landsat imagery; (3) determine relationships between landscape properties, climate and chromophoric dissolved organic matter levels and characteristics; and (4) elucidate relationships between dissolved organic matter characteristics and effects on water treatment. The proposed research will provide educational benefits for up to six individuals: a postdoctoral researcher, graduate research assistant, and 2-4 undergraduate students. The PIs will organize workshops for managers of regional water management agencies and make presentations at state conferences and meetings of citizen-based lake associations. Project results will be used to update a heavily used public database of lake water clarity (http://water.umn.edu) to include the chromophoric dissolved organic matter census and time-trend data and their relevance to citizens. Additional enhancements to the web site include a blog and an interactive interface for citizens to ask questions and share information. Finally, we will explore several possibilities to permit citizens to gather chromophoric dissolved organic matter data, including a low-tech color wheel comparator and cellphone app. Citizen engagement will be a key component of the project.