Impact of Dissolved Organic Matter Photodegradation on Carbon and Nitrogen Cycling in Freshwaters ...

• Main Author: Bowen, Jennifer
• Format: Article in Journal/Newspaper
• Language: English
• Published: My University 2021
• Subjects: freshwater biogeochemistry, dissolved organic matter, photochemistry; Geology and Earth Sciences; Science; Arctic
• Online Access: https://dx.doi.org/10.7302/3033; http://deepblue.lib.umich.edu/handle/2027.42/169988

Freshwaters emit comparable amounts of carbon dioxide (CO2) to the atmosphere as the net amount taken up by all land on Earth. The degradation of dissolved organic matter (DOM) to CO2 impacts these emissions from freshwaters, making the fate of DOM a critical component of the global carbon (C) cycle. Yet, controls on DOM degradation remain too poorly understood to quantify how much CO2 will be emitted from freshwaters as our planet warms. The sunlight-driven or photochemical degradation of DOM can impact freshwater CO2 emissions by producing CO2 or altering DOM to forms that are more or less labile to bacterial respiration to CO2. Photodegradation of DOM can also produce ammonium (NH4+), providing a source of nitrogen (N) to the primary producers carrying out photosynthetic uptake of CO2 in freshwaters. Here, chemical controls on these three photodegradation pathways were investigated and their impacts on C and N cycles were assessed in arctic and temperate freshwaters. First, the photochemical production of ...