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Assessment of the Vertical Stratification of Microbial Community Structure in Permafrost Peatlands

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Peatlands are a type of wetlands where the rate of accumulation of organic matter exceed the rate of decomposition and have accumulated more than 30 cm of peat (Joosten and Clark, 2002). Peatlands store approximately 30% of all terrestrial carbon

Peatlands are a type of wetlands where the rate of accumulation of organic matter exceed the rate of decomposition and have accumulated more than 30 cm of peat (Joosten and Clark, 2002). Peatlands store approximately 30% of all terrestrial carbon as recalcitrant peat, partially decomposed plant and microbial biomass, while simultaneously producing almost 40% of the globally emitted methane (Schmidt et al., 2016), making peatlands an important component of the carbon budgets. Published research indicates that the efficiency of carbon usage among microbial communities can determine the soil-carbon response to rising temperatures (Allison et al. 2010). By determining carbon consumption in peatland soils, total community respiration response, and community structure change with additions, models of carbon use efficiency in permafrost peatlands will be well-informed and have a better understanding of how the peatlands will respond to, and utilize, increased availability of carbon compounds due to the melting permafrost. To do this, we will sequence Lutose deep core samples to observe baseline microbial community structure at different depths and different age-gradients, construct substrate incubations of glucose and propionate and observe community respiration response via a gas chromatography flame ionization detector, track the glucose and propionate additions with high-performance liquid chromatography (HPLC), and sequence the samples once more to determine if there was a deviation from the initial community structure obtained prior to the incubations. We found that our initial sequencing data was supported by previous work (Lin et al., 2014), however we were unable to sequence samples post-incubation due to time constraints. In this sequencing analysis we found that the strongest variable that made samples biologically similar was the age-gradient site in which they were extracted. We found that the group with glucose additions produced the most carbon dioxide compared with the other treatments, but was not the treatment that dominated the production of methane. Finally, in the HPLC samples that were analyzed, we found that glucose is likely forming the most by-product accumulation from mass balance calculations, while propionate is likely forming the least. Future experimentation should focus on the shortcomings of this experiment. Further analysis of 16S rRNA sequencing data from after the incubations should be analyzed to determine the change in microbial community structure throughout the experiment. Furthermore, HPLC analysis for the several samples need to be done and followed up with mass balance to determine where the added glucose and propionate are being allocated within the soil. Once these pieces of the puzzle are put into place, our original question of how the microbial community structure changes at different depths and age-gradients within permafrost peatlands will be conclusively answered.

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2018-05

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The Environmental Contribution to Emerging Antibiotic Resistance

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Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15

Antibiotic resistance in the modern era has reached near-epidemic levels, resulting in much more difficult treatment of previously well-managed pathogens. Previous understandings of how antibiotic resistance emerges failed to account for the function of the environment. Over the past 15 years, new research has provided a link between the environmental and clinical spheres of antibiotic use. This data suggests that environmental bacteria, particularly those found in livestock farming ecosystems, may significantly contribute to the overall flow of antibiotic resistance genes into human populations. The main force behind this is the utilization of antibiotics as growth promoters in animal feed supplements, seeding individual animals and their surroundings with low doses of antibiotics. Notable increases in resistance have been observed within areas that utilize these supplements, as well as in connected but unrelated systems. Waste management strategies are poorly implemented, leading to the dispersal of contaminated runoff into groundwater and riverine environments. Furthermore, existing waste processing is limited in efficacy, often releasing large amounts of unprocessed antibiotics as well as a concentrated population of resistant bacteria. Within these resistant populations, horizontal gene transfer has emerged as a vehicle for the distribution of resistance genes into other populations of bacteria. Due to the prevalence of these transfer events, a new role for the environment as a reservoir and incubator of resistance genes is proposed. Current strategies for managing the spread of antibiotic resistance are woefully inadequate, and the continued emergence of new resistance mechanisms due to negligence highlights the need for global, multidisciplinary solutions. To corral the spread of antibiotic resistance, a system is proposed that utilizes metagenomic monitoring and the enforcement of core global policies to slow the advance of resistance while waiting for novel treatment strategies to bear fruit.

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2016-05