PT  - JOURNAL ARTICLE
AU  - Emily B. Graham
AU  - Malak Tfaily
AU  - Alex R. Crump
AU  - Amy E. Goldman
AU  - Evan Arntzen
AU  - Elvira Romero
AU  - C. Tom Resch
AU  - David W. Kennedy
AU  - James C. Stegen
TI  - Riparian vegetation limits oxidation of thermodynamically unfavorable bound-carbon stocks along an aquatic interface
AID  - 10.1101/105486
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 105486
4099  - http://biorxiv.org/content/early/2017/02/02/105486.short
4100  - http://biorxiv.org/content/early/2017/02/02/105486.full
AB  - In light of increasing terrestrial carbon (C) transport across aquatic boundaries, the mechanisms governing organic carbon (OC) oxidation along terrestrial-aquatic interfaces are crucial to future climate predictions. Here, we investigate biochemistry, metabolic pathways, and thermodynamics corresponding to OC oxidation in the Columbia River corridor. We leverage natural vegetative differences to encompass variation in terrestrial C inputs. Our results suggest that decreases in terrestrial C deposition associated with diminished riparian vegetation induce oxidation of physically-bound (i.e., mineral and microbial) OC at terrestrial-aquatic interfaces. We also find that contrasting metabolic pathways oxidize OC in the presence and absence of vegetation and—in direct conflict with the concept of ‘priming’—that inputs of water-soluble and thermodynamically-favorable terrestrial OC protects bound-OC from oxidation. Based on our results, we propose a mechanistic conceptualization of OC oxidation along terrestrial-aquatic interfaces that can be used to model heterogeneous patterns of OC loss under changing land cover distributions.