02975nas a2200289   4500008004100000245013500041210006900176260001200245490000600257520199400263653002902257653002302286653002402309653003102333653002602364653002602390100002602416700002402442700001602466700002002482700002202502700002602524700002502550700002302575700001702598856007002615       2018                        eng d00aStoichiometric Shifts in Soil C:N:P Promote Bacterial Taxa Dominance, Maintain Biodiversity, and Deconstruct Community Assemblages0 aStoichiometric Shifts in Soil CNP Promote Bacterial Taxa Dominan  c07/20180 v93 a<p>Imbalances in C:N:P supply ratios may cause bacterial resource limitations and constrain biogeochemical processes, but the importance of shifts in soil stoichiometry are complicated by the nearly limitless interactions between an immensely rich species pool and a multiple chemical resource forms. To more clearly identify the impact of soil C:N:P on bacteria, we evaluated the cumulative effects of single and coupled long-term nutrient additions (i.e., C as mannitol, N as equal concentrations NH4 + and NO3 &minus; , and P as Na3PO4) and water on communities in an Antarctic polar desert, Taylor Valley. Untreated soils possessed relatively low bacterial diversity, simplified organic C sources due to the absence of plants, limited inorganic N, and excess soil P potentially attenuating links between C:N:P. After 6 years of adding resources, an alleviation of C and N colimitation allowed one rare Micrococcaceae, an Arthrobacter species, to dominate, comprising 47% of the total community abundance and elevating soil respiration by 136% relative to untreated soils. The addition of N alone reduced C:N ratios, elevated bacterial richness and diversity, and allowed rare taxa relying on ammonium and nitrite for metabolism to become more abundant [e.g., nitrite oxidizing Nitrospira species (Nitrosomonadaceae), denitrifiers utilizing nitrite (Gemmatimonadaceae) and members of Rhodobacteraceae with a high affinity for ammonium]. Based on community co-occurrence networks, lower C:P ratios in soils following P and CP additions created more diffuse and less connected communities by disrupting 73% of species interactions and selecting for taxa potentially exploiting abundant P. Unlike amended nutrients, water additions alone elicited no lasting impact on communities. Our results suggest that as soils become nutrient rich a wide array of outcomes are possible from species dominance and the deconstruction of species interconnectedness to the maintenance of biodiversity.</p>10aecological stoichiometry10aLake Fryxell Basin10aMcMurdo Dry Valleys10anetwork community modeling10anutrient colimitation10aSolirubrobacteriaceae1 aAanderud, Zachary, T.1 aSaurey, Sabrina, D.1 aBall, Becky1 aWall, Diana, H.1 aBarrett, John, E.1 aMuscarella, Mario, E.1 aGriffin, Natasha, A.1 aVirginia, Ross, A.1 aAdams, Byron  uhttps://www.frontiersin.org/article/10.3389/fmicb.2018.01401/full03656nas a2200337   4500008004100000245005700041210005600098260004900154490001000203520257600213653001802789653002302807653003202830653003002862653001602892653002402908653003402932653002402966653002402990653002003014653005103034653002403085653001803109653002003127653003003147653002403177653003003201100002503231700001703256856004503273       2010                        eng d00aGenomic analysis of nematode-environment interaction0 aGenomic analysis of nematodeenvironment interaction  aProvo, UTbBrigham Young Universityc08/20100 vPh.D.3 a<p>The natural environments of organisms present a multitude of biotic and abiotic challenges that require both short-term ecological and long-term evolutionary responses. Though most environmental response studies have focused on effects at the ecosystem, community and organismal levels, the ultimate controls of these responses are located in the genome of the organism. Soil nematodes are highly responsive to, and display a wide variety of responses to changing environmental conditions, making them ideal models for the study of organismal interactions with their environment. In an attempt to examine responses to environmental stress (desiccation and freezing), genomic level analyses of gene expression during anhydrobiosis of the Antarctic nematode <em>Plectus murrayi</em> was undertaken. An EST library representative of the desiccation induced transcripts was established and the transcripts differentially expressed during desiccation stress were identified. The expressed genome of <em>P. murrayi</em> showed that desiccation survival in nematodes involves differential expression of a suite of genes from diverse functional areas, and constitutive expression of a number of stress related genes. My study also revealed that exposure to slow desiccation and freezing plays an important role in the transcription of stress related genes, improves desiccation and freezing survival of nematodes. Deterioration of traits essential for biological control has been recognized in diverse biological control agents including insect pathogenic nematodes. I studied the genetic mechanisms behind such deterioration using expression profiling. My results showed that trait deterioration of insect pathogenic nematode induces substantial overall changes in the nematode transcriptome and exhibits a general pattern of metabolic shift causing massive changes in metabolic and other processes. Finally, through field observations and molecular laboratory experiments the validity of the growth rate hypothesis in natural populations of Antarctic nematodes was tested. My results indicated that elemental stoichiometry influences evolutionary adaptations in gene expression and genome evolution. My study, in addition to providing immediate insight into the mechanisms by which multicellular animals respond to their environment, is transformative in its potential to inform other fundamental ecological and evolutionary questions, such as the evolution of life-history patterns and the relationship between community structure and ecological function in ecosystems.</p>10aanhydrobiosis10aAntarctic nematode10acomparative transcriptomics10acomplementary DNA library10adesiccation10afunctional analysis10aHeterorhabditis bacteriophora10aMcMurdo Dry Valleys10amicroarray analysis10aPlectus murrayi10aquantative real-time polymerase chain reaction10aScottnema lindsayae10astoichiometry10astress survival10asubtractive hybridization10atrait deterioration10atranscriptional profiling1 aAdhikari, Bishwo, N.1 aAdams, Byron  uhttps://scholarsarchive.byu.edu/etd/2578