College of Agriculture

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As the foundation of the land grant mission at Montana State University, the College of Agriculture and the Montana Agricultural Experiment Station provide instruction in traditional and innovative degree programs and conduct research on old and new challenges for Montana’s agricultural community. This integration creates opportunities for students and faculty to excel through hands-on learning, to serve through campus and community engagement, to explore unique solutions to distinct and interesting questions and to connect Montanans with the global community through research discoveries and outreach.

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Author: search.filters.author.Baumann, Adamsearch.filters.applied.f.department: search.filters.department.Land Resources & Environmental Sciences.

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    Sustained stoichiometric imbalance and its ecological consequences in a large oligotrophic lake
    (Proceedings of the National Academy of Sciences, 2022-07) Elser, James J.; Devlin, Shawn P.; Yu, Jinlei; Baumann, Adam; Church, Matthew J.; Dore, John E.; Hall, Robert O.; Hollar, Melody; Johnson, Tyler; Vick-Majors, Trista; White, Cassidy
    Considerable attention is given to absolute nutrient levels in lakes, rivers, and oceans, but less is paid to their relative concentrations, their nitrogen:phosphorus (N:P) stoichiometry, and the consequences of imbalanced stoichiometry. Here, we report 38 y of nutrient dynamics in Flathead Lake, a large oligotrophic lake in Montana, and its inflows. While nutrient levels were low, the lake had sustained high total N: total P ratios (TN:TP: 60 to 90:1 molar) throughout the observation period. N and P loading to the lake as well as loading N:P ratios varied considerably among years but showed no systematic long-term trend. Surprisingly, TN:TP ratios in river inflows were consistently lower than in the lake, suggesting that forms of P in riverine loading are removed preferentially to N. In-lake processes, such as differential sedimentation of P relative to N or accumulation of fixed N in excess of denitrification, likely also operate to maintain the lake’s high TN:TP ratios. Regardless of causes, the lake’s stoichiometric imbalance is manifested in P limitation of phytoplankton growth during early and midsummer, resulting in high C:P and N:P ratios in suspended particulate matter that propagate P limitation to zooplankton. Finally, the lake’s imbalanced N:P stoichiometry appears to raise the potential for aerobic methane production via metabolism of phosphonate compounds by P-limited microbes. These data highlight the importance of not only absolute N and P levels in aquatic ecosystems, but also their stoichiometric balance, and they call attention to potential management implications of high N:P ratios.
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    Differentiating Sources of Fecal Contamination to Wilderness Waters Using Droplet Digital PCR and Fecal Indicator Bacteria Methods
    (2021-06) Pendergraph, Daniel P.; Ranieri, John; Ermatinger, Lochlin; Baumann, Adam; Metcalf, Alexander L.; DeLuca, Thomas H.; Church, Matthew J.
    Introduction Human activity in wilderness areas has the potential to affect aquatic ecosystems, including through the introduction of microorganisms associated with fecal contamination. We examined fecal microorganism contamination in water sources (lake outlets, snowmelt streams) in the popular Absaroka Beartooth Wilderness in the United States. Although the region is remote, increasing human visitation has the potential to negatively affect water quality, with particular concern about human-derived microorganism fecal contaminants. Methods We used standard fecal indicator bacterial assays that quantified total coliform bacteria and Escherichia coli concentrations, together with more specific polymerase chain reaction-based microbial assays that identified possible human sources of fecal microorganisms in these waters. Results Total coliforms were detected at all lake outlets (21 of 21 sites), and E coli was detected at 11 of 21 sites. Droplet digital polymerase chain reaction assays revealed the presence of human feces-derived microorganisms, albeit at abundances below the limit of detection (<10 gene copies per milliliter of water) at all but 1 of the sampling sites. Conclusions Our results suggest low prevalence of water-borne pathogens (specifically E coli and human-derived Bacteroides) in this popular wilderness area. However, widespread detection of total coliforms, Bacteroides, and E coli highlight the importance of purifying water sources in wilderness areas before consumption. Specific sources of total coliforms and E coli in these waters remain unknown but could derive from wild or domesticated animals that inhabit or visit the Absaroka Beartooth Wilderness. Hence, although contamination by human fecal microorganisms appears minimal, human visitation could indirectly influence fecal contamination through domesticated animals.
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