Photochemical alteration of organic carbon draining permafrost soils shifts microbial metabolic pathways and stimulates respiration

Last modified: 
December 16, 2019 - 12:01pm
Type: Journal Article
Year of publication: 2017
Date published: 10/2017
Authors: Collin Ward, Sarah Nalven, Byron Crump, George Kling, Rose Cory
Journal title: Nature Communications
Volume: 8
Issue: 1

In sunlit waters, photochemical alteration of dissolved organic carbon (DOC) impacts the microbial respiration of DOC to CO2. This coupled photochemical and biological degradation of DOC is especially critical for carbon budgets in the Arctic, where thawing permafrost soils increase opportunities for DOC oxidation to CO2 in surface waters, thereby reinforcing global warming. Here we show how and why sunlight exposure impacts microbial respiration of DOC draining permafrost soils. Sunlight significantly increases or decreases microbial respiration of DOC depending on whether photo-alteration produces or removes molecules that native microbial communities used prior to light exposure. Using high-resolution chemical and microbial approaches, we show that rates of DOC processing by microbes are likely governed by a combination of the abundance and lability of DOC exported from land to water and produced by photochemical processes, and the capacity and timescale that microbial communities have to adapt to metabolize photo-altered DOC.

Freely available?: 
Yes
Summary available?: 
No