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- Member of: Barrett, The Honors College Thesis/Creative Project Collection
- Status: Published
In this study, the influence of fluid mixing on temperature and geochemistry of hot spring fluids is investigated. Yellowstone National Park (YNP) is home to a diverse range of hot springs with varying temperature and chemistry. The mixing zone of interest in this paper, located in Geyser Creek, YNP, has been a point of interest since at least the 1960’s (Raymahashay, 1968). Two springs, one basic (~pH 7) and one acidic (~pH 3) mix together down an outflow channel. There are visual bands of different photosynthetic pigments which suggests the creation of temperature and chemical gradients due to the fluids mixing. In this study, to determine if fluid mixing is driving these changes of temperature and chemistry in the system, a model that factors in evaporation and cooling was developed and compared to measured temperature and chemical data collected downstream. Comparison of the modeled temperature and chemistry to the measured values at the downstream mixture shows that many of the ions, such as Cl⁻, F⁻, and Li⁺, behave conservatively with respect to mixing. This indicates that the influence of mixing accounts for a large proportion of variation in the chemical composition of the system. However, there are some chemical constituents like CH₄, H₂, and NO₃⁻, that were not conserved, and the concentrations were either depleted or increased in the downstream mixture. Some of these constituents are known to be used by microorganisms. The development of this mixing model can be used as a tool for predicting biological activity as well as building the framework for future geochemical and computational models that can be used to understand the energy availability and the microbial communities that are present.
This formula was used to estimate the nutrient uptake performance of aquatic primary producers from sampling observations; ANPP accounted for 16.26 metric tons of system wide N uptake, while aquatic ER contributed 6.07 metric tons N of nighttime remineralization and 5.7 metric tons of N throughout the water column during the day. The estimated yearly net aquatic N flux is 4.49 metric tons uptake, compared to about 12 metric tons yearly N uptake by the vegetated marsh (Treese, 2019). However, not accounting for animal respiration results in an underestimation of system-wide N remineralization, and not accounting for soil processes results in an underestimation of N uptake.