Abstract

Soils play an important role in storing carbon as organic matter and soils globally contain twice as much carbon as the atmosphere. Organic matter can be protected from decomposition and sequestered in the soil for decades to millennia in a number of ways, including chemical recalcitrance that makes it resistant to decomposition and through stabilization interactions with mineral surfaces. Here, we examined organic matter associations with mineral surfaces in the soils of the Huff Run watershed, which has been severely impacted by coal mining activity. We hypothesized that organic matter in these soils is at least partially stabilized through interactions with different soil minerals, such as iron and manganese oxides. To address this hypothesis, we tested a new method to sequentially extract organic matter from a 140 cm soil profile from Huff Run. We extracted soil organic matter in water soluble, “free” particulate, bound to manganese oxides, and bound to iron and aluminum oxides fractions. We measured the concentrations of aluminum, calcium, iron, magnesium and manganese in each fraction using inductively-coupled plasma optical emission spectroscopy (ICP-OES). We measured the organic carbon content of our water soluble and manganese oxide associated fractions using a total organic carbon analyzer (TOC-L). We also ran quality control extractions on the 70-80 cm sample, a layer containing high concentrations of manganese oxides. Initial results indicate our method extracted the intended fractions, but further analysis is required to ascertain whether or not organic matter is being associated with soil minerals at Huff Run.

Modified Abstract

Soils play an important role in storing carbon as organic matter. Here, we examined organic matter storage in the soils of the Huff Run watershed. We hypothesized that organic matter in these soils is stabilized through interactions with soil minerals. To address this, we tested a new method to sequentially extract four different organic matter fractions from a 140 cm soil profile from Huff Run. We analyzed metal concentrations and organic carbon content of our fractions using inductively-coupled plasma optical emission spectroscopy (ICP-OES) and a total organic carbon analyzer (TOC-L), respectively. We ran quality control extractions and found that our method extracted the intended fractions, but further analysis is required to ascertain whether or not organic matter is associating with soil minerals at Huff Run.

Research Category

Geology/Geography

Primary Author's Major

Earth Science

Mentor #1 Information

Dr. Elizabeth Herndon

Presentation Format

Poster

Roundtable Moderator

Dr. Elizabeth Herndon

Start Date

5-4-2018 1:00 PM

Research Area

Earth Sciences | Environmental Sciences | Soil Science

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Apr 5th, 1:00 PM

Developing a protocol for extracting mineral-associated organic matter in soils developed from coal mine waste

Soils play an important role in storing carbon as organic matter and soils globally contain twice as much carbon as the atmosphere. Organic matter can be protected from decomposition and sequestered in the soil for decades to millennia in a number of ways, including chemical recalcitrance that makes it resistant to decomposition and through stabilization interactions with mineral surfaces. Here, we examined organic matter associations with mineral surfaces in the soils of the Huff Run watershed, which has been severely impacted by coal mining activity. We hypothesized that organic matter in these soils is at least partially stabilized through interactions with different soil minerals, such as iron and manganese oxides. To address this hypothesis, we tested a new method to sequentially extract organic matter from a 140 cm soil profile from Huff Run. We extracted soil organic matter in water soluble, “free” particulate, bound to manganese oxides, and bound to iron and aluminum oxides fractions. We measured the concentrations of aluminum, calcium, iron, magnesium and manganese in each fraction using inductively-coupled plasma optical emission spectroscopy (ICP-OES). We measured the organic carbon content of our water soluble and manganese oxide associated fractions using a total organic carbon analyzer (TOC-L). We also ran quality control extractions on the 70-80 cm sample, a layer containing high concentrations of manganese oxides. Initial results indicate our method extracted the intended fractions, but further analysis is required to ascertain whether or not organic matter is being associated with soil minerals at Huff Run.