PEDOGENIC FATE AND TRANSPORT OF TOTAL MERCURY ACROSS SUBAERIAL AND SUBAQUEOUS SOILS IN AN APPALACHIAN PLATEAU IMPOUNDMENT
Open Access
- Author:
- Erich, Emilie Luise
- Graduate Program:
- Soil Science
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- August 24, 2010
- Committee Members:
- Patrick Joseph Drohan, Thesis Advisor/Co-Advisor
Patrick Joseph Drohan, Thesis Advisor/Co-Advisor - Keywords:
- subaqueous
soil
management
mercury - Abstract:
- A new field of soil science classifies plant-supporting materials undergoing pedogenesis in up to 2.5 m of water as subaqueous soil (SAS). SAS experience the same soil forming factors and pedogenic processes as terrestrial soils, but are dominated by conditions of submergence. Most SAS research has occurred in coastal and marine environments, and has yet to explore SASs in freshwater systems. Freshwater SAS research can enhance freshwater resource management for carbon sequestration potential, pollution control, and other ecological concerns by illustrating SAS properties and their soil-landscape relationship, and developing soil interpretations for specific management issues. SASs of Black Moshannon Lake were characterized, taxonomically classified, and mapped across the lake. Gleying, increases in surface organic matter, lithologic discontinuity, and relict fragic properties were predominant characteristics of the three observed SASs, classified as a Histic Hydrowassult, a Typic Hydrowassult, and a Fragic Hydrowassult. Pennsylvania has an abundance of surface water resources, however many are impacted by mercury, including the study site at Black Moshannon Lake. The distribution of Hg and SOC (with which Hg is commonly associated) was determined across a hydrosequence, including SASs, in the Black Moshannon Lake watershed. Both Hg and SOC accumulation and transport were greatly influenced by soil drainage, organic matter content, and the presence of a fragipan. SOC pools increased with wetness, and were greatest in SASs, while Hg pools decreased with wetness, indicating a loss of Hg to the aquatic system and likely Hg methylation. Greater SOC pools with smaller Hg pools indicates SASs can be managed for carbon sequestration without Hg sequestration. The cartographic representation of SASs with the interpretation of their characteristics provides a useful management tool for freshwater ecosystem management.