Life at Interfaces: Biocomplexity in Extreme Environments

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WELCOME to the NEW VERSION of the Idaho EPSCoR "Biocomplexity in Extreme Environments" webpage!

GEOCHEMISTRY:

Summary of results:

Principal Investigator: Scott Wood (UI)

The chemical components of spring water serve as sources of energy and nutrients for biological communities living in hot springs; in turn, the metabolic processes of biological agents influence water chemistry and play an important role in the formation of mineral precipitates within the springs. Because geologic, hydrologic, and geothermal factors set the stage for these complex biological-chemical interactions, an understanding of aqueous geochemistry is pivotal to the interdisciplinary Biocomplexity project. The geochemistry research group seeks to demonstrate linkages between the biological and geological factors that set stage for microbial growth in the geothermal springs of the Alvord Basin. Geochemical sampling of geothermal springs, geothermal wells, and ambient temperature springs has yielded information on the characteristics of the geothermal reservoirs, water/rock interactions in the subsurface environment, and the source of geothermal waters in the Alvord Basin.
geochemical sampling at Mickey Hot Springs
UI students collect water samples at Mickey Hot Springs.

Rare Earth Elements

Below is a plot of the chondrite-normalized rare earth element (REE) concentrations of selected hot springs from the Alvord Basin (samples collected Oct 1998). Symbols connected by solid lines represent data from unfiltered samples, and those connected by dotted lines represent data from samples filtered through a 0.45-micron filter.

Rare earth element concentrations in Alvord Basin geothermal springs
Rare earth element (REE) concentrations in Alvord Basin geothermal springs.

[Click image to enlarge]

The absolute REE concentrations and the trends of the normalized patterns are typical of waters from continental geothermal systems around the world. Note that, with the exception of Alvord Hot Springs, the filtered samples have at least one order of magnitude less REE than the unfiltered samples, suggesting the REE load is dominated by suspended particles.
Major Ion Chemistry

Geochemical data for select hot springs in the Alvord Basin have been collected several times a year for the past three years. The data indicate that no mixing occurs between geothermal fluids and ambient groundwater. Additionally, there is little variation in chemistry within each hot spring group (e.g., Borax), and chemistries appear to be similar between hot springs groups (Borax, Mickey, and Alvord).

Piper diagram of water chemistries from Alvord Basin springs
Piper diagram of water chemistries for Borax, Alvord, and Mickey hot springs, along with chemistries from a flowing well near Borax Lake and from three cold springs on Steens Mountain west of Borax Lake. The number in parentheses (in the legend) refers to the number of springs sampled at a location. [Click image to enlarge]

In cooperation with the UI Geochemistry group, the UI Computational Hydrology group conducted exhaustive geochemical sampling of all hot springs for which water samples could be obtained at Borax and Mickey (171 and 27 springs respectively) during May-June 2003. Unfiltered water samples were analyzed for concentrations (mg/L) of twenty-two elements. The data are summarized in bar graphs at the following links, while tabular data can be obtained through the Data Resources link on this website.
last update: June 2006 | webmaster: jhinds@uidaho.edu