Submitted by Matthew Potts on
The Amazonian region of Madre de Dios, Peru is undergoing rapid environmental and social change as a result of the expansion of informal gold mining. Along with deforestation, informal gold mining in Madre de Dios utilizes toxic mercury. Mercury is used in mining to separate and bind diffuse gold particles found in alluvial soils. Mercury and gold bind together to form a complex or amalgam that is later roasted to purify the gold. The burning of this amalgam releases mercury vapor into the atmosphere, while the addition of mercury to sediments also leads to its accidental release into waterways. As a result, there has been an increase in efforts to understand the ecological and human health implications of mercury contamination in the region.
This project seeks to understand how mercury spreads beyond the boundaries of a gold mine and into aquatic and terrestrial ecosystems via food web interactions. Informal gold mining creates landscapes of abandoned mining pits. These mining pits cover greater than 20% of the total area deforested as a result of gold mining. The mining pits are colonized by fish, insects, birds, and reptiles when nearby rivers flood and fill the abandoned pits. These man-made systems become potential sources of mercury for the rest of the ecosystem as mercury enters the food web and increases in concentration or biomagnifies up the food chain. As one part of this project, we have collected emerging aquatic insects to study how mercury moves laterally from mining pits into surrounding forested ecosystems. These emerging insects become prey for spiders (Family: Tetragnathidae) found in mining pits. Bats, birds and other small mobile predators in turn predate upon these spiders and increasingly magnify the effects of mercury contamination in these tropical food webs. To understand the potential effects of this lateral transfer we will identify and analyze the mercury content of aquatic insects and spiders in these mining pits.
The undergraduate with the support of the graduate student mentor will help design, analyze, and write-up a research project related to the movement of mercury between aquatic and terrestrial ecosystems.
The undergraduate should be willing to work on taxonomic identification of insects involving many hours at a microscope. The undergraduate should be self-motivated and able to work with limited guidance. Knowledge of aquatic insect identification is a plus. The graduate student mentor is also committed to working closely with the undergraduate to develop and make progress towards his or her own personal career goals.