Sponsor
This research was supported by a NASA PSTAR grant (80NSSC18K1738) for THOR (Thermal High-voltage Ocean-penetrator Research platform). Partial support was also provided (to B.C.C. and Q.F.) by a grant from the National Science Foundation (OPP-2000649) and the University of Florida’s Water Institute Graduate Fellowship program.
Published In
JGR Biogeosciences
Document Type
Article
Publication Date
9-28-2022
Subjects
Geothermal -- Water-- Washington (State) -- Mount Saint Helens
Abstract
Environments where geothermal waters and glacier meltwater mix are common on Earth yet little is known about the biogeochemical processes that occur when hot, reduced geothermal water mixes with cold, oxidized glacial meltwater in natural systems. Mount St. Helens provides an ideal location to study the interaction between geothermal and glacier waters since the water sources, and their mixing environment in Step Creek, are exposed in the volcanic crater. We find that the two water sources contain distinct major ion, trace element, dissolved organic matter (DOM), and biological signatures. The hot spring contains high concentrations of biogeochemically reactive components (e.g., siderophile and chalcophile trace elements and DOM) compared to the glacier discharge but a large fraction of these solutes do not remain in solution after the waters mix. In contrast, glacier discharge contains fewer solutes but most of these solutes remain in solution after the waters mix. The mixing of glacier and hot spring water in Step Creek supports seston and benthic ecosystems that have higher phototrophic and microbial biomass than those in the source waters, suggesting that the mixing environment in this high-gradient stream provide a more comprehensive suite of soluble and essential nutrients that promote primary production and DOM cycling.
Rights
© 2022 American Geophysical Union
Locate the Document
DOI
10.1029/2022JG006852
Persistent Identifier
https://archives.pdx.edu/ds/psu/38852
Citation Details
Dubnick, A., Faber, Q., Hawkings, J. R., Bramall, N., Christner, B. C., Doran, P. T., ... & Skidmore, M. L. (2022). Biogeochemical responses to mixing of glacial meltwater and hot spring discharge in the Mount St. Helens crater. Journal of Geophysical Research: Biogeosciences, 127(10), e2022JG006852.