Title of Oral/Poster Presentation

EVIDENCE FOR PRIMING: LIGHT DEGRADED DISSOLVED ORGANIC MATTER INCREASED THE DECAY RATE OF TERRESTRIAL ORGANIC MATTER IN EXPERIMENTAL STREAMS

Presenter Information

Julia KelsoFollow

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

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Apr 13th, 12:00 PM Apr 13th, 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.