EVIDENCE FOR PRIMING: LIGHT DEGRADED DISSOLVED ORGANIC MATTER INCREASED THE DECAY RATE OF TERRESTRIAL ORGANIC MATTER IN EXPERIMENTAL STREAMS
Class
Article
Graduation Year
2017
College
College of Science
Department
Biology Department
Faculty Mentor
Michelle Baker
Presentation Type
Oral Presentation
Abstract
Dissolved organic matter (DOM) is the largest pool of organic matter (OM) in natural aquatic systems and mediates all microbial processes. Biogeochemists have described a process called priming where small additions of labile OM accelerate decomposition of semi-labile OM. We tested for the priming effect in 8 experimental streams and dark bottles at the Cary Institute of Ecosystem Studies. We measured decay of 2 forms of semi-labile DOM: soil and plant leachates, 2 forms of labile DOM: algal leachate and light degraded semi-labile DOM, and mixtures of labile and semi-labile DOM. Soil leachate decay rates were negligible and plant leachate averaged 0.011/hr in streams and 0.001/hr in bottles (S.D . 0.002/hr and 0.001/hr). Algal leachate decay averaged 0.025/hr in streams and 0.005/hr in bottles (S.D. 0.021/hr and 0.002/hr). When algal leachate was mixed with semi-labile plant leachate decay rates were similar to plant leachate alone. However, when light-degraded plant leachate was added to semi-lable leachate, decay rates were greater than plant leachate alone. We conclude exposure to light increased lability of terrestrially derived DOM, and could increase the consumption rate of non-labile DOM.
Location
Room 154
Start Date
4-13-2017 12:00 PM
End Date
4-13-2017 1:15 PM
EVIDENCE FOR PRIMING: LIGHT DEGRADED DISSOLVED ORGANIC MATTER INCREASED THE DECAY RATE OF TERRESTRIAL ORGANIC MATTER IN EXPERIMENTAL STREAMS
Room 154
Dissolved organic matter (DOM) is the largest pool of organic matter (OM) in natural aquatic systems and mediates all microbial processes. Biogeochemists have described a process called priming where small additions of labile OM accelerate decomposition of semi-labile OM. We tested for the priming effect in 8 experimental streams and dark bottles at the Cary Institute of Ecosystem Studies. We measured decay of 2 forms of semi-labile DOM: soil and plant leachates, 2 forms of labile DOM: algal leachate and light degraded semi-labile DOM, and mixtures of labile and semi-labile DOM. Soil leachate decay rates were negligible and plant leachate averaged 0.011/hr in streams and 0.001/hr in bottles (S.D . 0.002/hr and 0.001/hr). Algal leachate decay averaged 0.025/hr in streams and 0.005/hr in bottles (S.D. 0.021/hr and 0.002/hr). When algal leachate was mixed with semi-labile plant leachate decay rates were similar to plant leachate alone. However, when light-degraded plant leachate was added to semi-lable leachate, decay rates were greater than plant leachate alone. We conclude exposure to light increased lability of terrestrially derived DOM, and could increase the consumption rate of non-labile DOM.