Increase in biological DOM removal by photopriming in inland waters - where and how it works
Abstract
The amount and the composition of dissolved organic matter (DOM) in freshwater systems have significant implications for water quality, carbon cycling, and aquatic ecology. Understanding what controls DOM is critical in improving our large scale models and best management practices for aquatic ecosystems. Recent studies identified that sunlight and microbes can synergistically alter the chemical composition of organic matter and boost the total removal rate. Yet, our knowledge of the prevalence and strength this "primed" removal mechanism is very limited. This study shows that priming between biological and photochemical organic matter removal can occur almost anywhere and anytime in temperate fresh water systems, and that sunlight can increase the efficiency of microbial removal by threefold on average. Further analysis of individual DOM components by Fourier transform ion cyclotron resonance mass spectrometry shows that biological and photochemical DOM processes have markedly different dynamics in their removal efficiency. In particular, a synergy between efficient microbial uptake of nitrogen containing molecules with high H/C and efficient production of such molecules by sunlight is identified as the main driver of photopriming. While most natural rivers do not have long enough residence times to fully utilize photopriming for DOM removal, dams and reservoirs serve as photopriming hotspots due to their long residence time and reduced light attenuation.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H31M2129Y
- Keywords:
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- 0432 Contaminant and organic biogeochemistry;
- BIOGEOSCIENCESDE: 0481 Restoration;
- BIOGEOSCIENCESDE: 1830 Groundwater/surface water interaction;
- HYDROLOGYDE: 1871 Surface water quality;
- HYDROLOGY