Bioavailability of Leachable Dissolved Organic Carbon from Subnival Soils

Conference Year

January 2020

Abstract

Over the past few decades, freshwater streams in the North Eastern U.S. have seen significant changes in concentrations of Dissolved Organic Carbon (DOC). During this same time, forested catchments in the North Eastern U.S. have experienced increases in pH as these systems have begun to recover from acid rain deposition and a connection between recovery and DOC dynamics seems likely. Because in snow-dominated systems snowmelt constitutes a very significant hydrologic event that can flush DOC from soils into streams, winter processes must be studied carefully. We hypothesize that during the wintertime, the cold temperatures limit subnival (under snowpack) microbial activity, allowing soils to accumulate large amounts of organic material that is available for flushing. We also hypothesize that these materials will be very biodegradable as soon as it enters the stream. To test these hypotheses we sampled subnival soil cores from Sleepers River Research Watershed in Northeastern Vermont and leached the soils with several types of solution of varying ionic strength and pH. We also incubated each set of samples to quantify biodegradability. Results from these experiments will provide useful information on the mechanism of DOC liberation during recovery form acidification and biodegradability of soil-derived DOC during winter times.

Primary Faculty Mentor Name

Julia Perdrial

Graduate Student Mentors

Caitlin Bristol, Thomas Adler

Faculty/Staff Collaborators

Caitlin Bristol, Thomas Adler, Jamie Shanley, Andrea Lini, Julia Perdrial

Status

Undergraduate

Student College

College of Arts and Sciences

Program/Major

Environmental Sciences

Primary Research Category

Engineering & Physical Sciences

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Bioavailability of Leachable Dissolved Organic Carbon from Subnival Soils

Over the past few decades, freshwater streams in the North Eastern U.S. have seen significant changes in concentrations of Dissolved Organic Carbon (DOC). During this same time, forested catchments in the North Eastern U.S. have experienced increases in pH as these systems have begun to recover from acid rain deposition and a connection between recovery and DOC dynamics seems likely. Because in snow-dominated systems snowmelt constitutes a very significant hydrologic event that can flush DOC from soils into streams, winter processes must be studied carefully. We hypothesize that during the wintertime, the cold temperatures limit subnival (under snowpack) microbial activity, allowing soils to accumulate large amounts of organic material that is available for flushing. We also hypothesize that these materials will be very biodegradable as soon as it enters the stream. To test these hypotheses we sampled subnival soil cores from Sleepers River Research Watershed in Northeastern Vermont and leached the soils with several types of solution of varying ionic strength and pH. We also incubated each set of samples to quantify biodegradability. Results from these experiments will provide useful information on the mechanism of DOC liberation during recovery form acidification and biodegradability of soil-derived DOC during winter times.