Water Resources Research Act Program

Details for Project ID 2014VT75B

Organic phosphorus forms and transformations in Lake Champlain stream corridor soils

Institute: Vermont
Year Established: 2014 Start Date: 2014-03-01 End Date: 2016-02-28
Total Federal Funds: $80,315 Total Non-Federal Funds: $161,983

Principal Investigators: Donald Ross, Beverley Wemple

Abstract: Understanding the mechanisms of bioavailable phosphorus (P) delivery from the landscape to fresh water bodies remains a key need. Recent work has shown that streambank erosion is responsible for a large portion of the sediment load entering Lake Champlain. The speciation and reactivity of the P in that sediment has not been adequately researched. Our recent work has shown that concentrations of soil test P (correlated with bioavailable P) are usually relatively low in near-stream soils and streambanks—even when high in adjacent land use. Additionally, we have shown that a large portion of the bioavailable P is in an organic form. Organic soil P is much less understood than inorganic phosphate, largely because of the difficulties involved in analysis. We propose to use a new microplate reader technique, developed by other researchers at UVM, to perform enzyme hydrolysis studies that reveal both the quantity and character of soil organic P. We will take advantage of past sampling funded by the Water Center and ongoing sampling that is supporting research on P transformations in the Missisquoi Bay. Soils adjacent to specific land uses will be analyzed for total organic P and the organic fraction then separated into reactive monoester P and nucleic (diester) P. This procedure will also be used to determine inorganic and organic P species classes in soil extractions designed to remove the bioavailable P fraction. A series of experiments will be performed to determine the release potential of both inorganic and organic P of the whole soil and the fine soil fraction that would be more likely to be transported to the lake. The soil sampling will be designed to also determine if narrower field buffer width leads to higher P in near-stream soils. This project will train a Ph.D. student and at least two undergraduate students. The results will increase our knowledge on the mechanisms and forms of bioavailable that move into the lake following the erosion of streambank soils.