A Geochemical Trophic Cascade in Yellowstone's Geothermal Environments

Ecosystems
By: , and 

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Abstract

We contrast the geochemistry of the Madison drainage, which has high concentrations of geothermal features, with the Lamar drainage of Yellowstone National Park, USA, and trace the consequences of geochemical differences through abiotic and biotic linkages in the ecosystem. Waters in the geothermal-dominated drainage contained anomalously high levels of fluoride (F) and silica (SiO2). Soils, stream sediments, and surface waters that interact or mix with geothermal waters, in turn, had elevated F and SiO2 concentrations compared to similar samples from the Lamar drainage. The geochemical differences were reflected in the chemistry of forage plants, with some plants from geothermally influenced areas containing four- to eightfold higher concentrations of F and SiO2 than similar plants in the Lamar drainage. Geothermal heat reduced snowpack, and we found that elk (Cervus elaphus) concentrated in these refugia as snowpack increased each winter. The consequent high dietary intake of F in animals associated with the geothermal areas was confirmed by the finding that bone samples from elk living in the Madison drainage contained sixfold higher concentrations of F than samples collected from animals wintering in the Lamar drainage. High F exposure resulted in compromised dentition due to fluoride toxicosis, which was undoubtedly exacerbated by the abrasive action of silica. The consequent accelerated and aberrant tooth wear resulted in early onset of senescence, reduced life span, and an abbreviated age structure. We speculate that these altered demographics, combined with spatial heterogeneity of snowpack, will result in increased vulnerability of this large herbivore population to wolf predation and less resiliency to compensate demographically for predation.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title A Geochemical Trophic Cascade in Yellowstone's Geothermal Environments
Series title Ecosystems
DOI 10.1007/s10021-002-0211-8
Volume 5
Year Published 2002
Language English
Publisher Springer Nature
Contributing office(s) Central Energy Resources Science Center
Description 8 p.
First page 659
Last page 666
Country United States
State Wyoming
Other Geospatial Yellowstone National Park
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