The Impact of Colonizer Plants on Bacterial Community Structure and Function in Early Successional Soils of a Glacial Forefield

Through litter inputs, root exudates, and the resulting changes in soil chemistry, plants directly interact with the soil microbial community. Recent research on plant-microbe interactions suggests that soil microbial community structure and function play an integral role in plant community succession through both positive and negative feedbacks; yet, plant-microbe dynamics along a successional gradient have not been well-studied. My study in the recently exposed soils of the Mendenhall Glacier forefield near Juneau, AK, USA examined the development of microbial communities in coordination with the establishment of the first plants. The Mendenhall Glacier features a perhumid climate, with moist soils throughout the year, and nearby vegetation that serves as a propagule source, facilitating relatively rapid plant colonization. I sampled soils under two different plant species (alder, Alnus sinuata and spruce, Picea sitchensis) and from unvegetated areas. All samples were gathered within a single transect of soils that had been exposed for 6 years. For each sample site soil pH, organic carbon (C), available nitrogen (N), bioavailable (Olsen) Phosphorus (P), microbial biomass C, and nitrogen fixation rates were determined. My research shows specific vegetation type differences in bacterial community structure and the general enrichment of α-Proteobacteria in vegetated soils. Soil nutrient and carbon pools did not correlate with bacterial community composition. Interestingly, although pH did not significantly vary by vegetation type, it was the only parameter that correlated with bacterial community structure. My study revealed a significant correlation between nitrogen fixation rates and bacterial community composition, a feedback with potentially important impacts for the ecology of these environments. Vegetation type explained more variation in differences in bacterial communities than pH, suggesting that plant acidification of soils only partly drive broad shifts in bacterial communities. Plant species-specific differences in bacterial community structure may also relate to the chemical composition of litter and root exudates. Additionally, plant carbon inputs in general likely enhance asymbiotic N-fixer function in these relatively new soils where nitrogen limitations may stifle bacterial growth. My study provides insights into how colonizer plants drive changes in bacterial community structure and function in a glacial forefield, altering bacterial succession and ecosystem development

The Tourist Citizen Diplomat

This paper introduces a role of citizen diplomat for tourists. The concept of innovative diplomacy, i.e. citizen and municipal diplomacy is applied to tourism. A model of a tourist diplomat guide is outlined, using Canada as the host country. Critical to this guide is describing the identity of the host country through a list of basic elements and situating the role of tourist diplomat in a global context of issues. Peace, human rights and environmental protection are the major issue categories of the context. Given space limitations, the section on the identity of the host country is compressed into an overview essay while the broad issue of peace is chosen to illustrate the global context. This model will provide the basis for the production of full tourist diplomat guides for the U.S.S.R. and People\u27s Republic of China

Microbes as Engines of Ecosystem Function: When Does Community Structure Enhance Predictions of Ecosystem Processes?

Microorganisms are vital in mediating the earth’s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: ‘When do we need to understand microbial community structure to accurately predict function?’ We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology

Microbes as engines of ecosystem function : When does community structure enhance predictions of ecosystem processes?

FUNDING This work was supported by NSF grant DEB-1221215 to DN, as well as grants supporting the generation of our datasets as acknowledged in their original publications and in Supplementary Table S1. ACKNOWLEDGMENT We thank the USGS Powell Center ‘Next Generation Microbes’ working group, anonymous reviews, Brett Melbourne, and Alan Townsend for valuable feedback on this project.Peer reviewedPublisher PD

Microbes as engines of ecosystem function: When does community structure enhance predictions of ecosystem processes?

Microorganisms are vital in mediating the earth\u27s biogeochemical cycles; yet, despite our rapidly increasing ability to explore complex environmental microbial communities, the relationship between microbial community structure and ecosystem processes remains poorly understood. Here, we address a fundamental and unanswered question in microbial ecology: \u27When do we need to understand microbial community structure to accurately predict function?\u27 We present a statistical analysis investigating the value of environmental data and microbial community structure independently and in combination for explaining rates of carbon and nitrogen cycling processes within 82 global datasets. Environmental variables were the strongest predictors of process rates but left 44% of variation unexplained on average, suggesting the potential for microbial data to increase model accuracy. Although only 29% of our datasets were significantly improved by adding information on microbial community structure, we observed improvement in models of processes mediated by narrow phylogenetic guilds via functional gene data, and conversely, improvement in models of facultative microbial processes via community diversity metrics. Our results also suggest that microbial diversity can strengthen predictions of respiration rates beyond microbial biomass parameters, as 53% of models were improved by incorporating both sets of predictors compared to 35% by microbial biomass alone. Our analysis represents the first comprehensive analysis of research examining links between microbial community structure and ecosystem function. Taken together, our results indicate that a greater understanding of microbial communities informed by ecological principles may enhance our ability to predict ecosystem process rates relative to assessments based on environmental variables and microbial physiology

Toward a Generalizable Framework of Disturbance Ecology Through Crowdsourced Science

© 2021 Graham, Averill, Bond-Lamberty, Knelman, Krause, Peralta, Shade, Smith, Cheng, Fanin, Freund, Garcia, Gibbons, Van Goethem, Guebila, Kemppinen, Nowicki, Pausas, Reed, Rocca, Sengupta, Sihi, Simonin, Słowiński, Spawn, Sutherland, Tonkin, Wisnoski, Zipper and Contributor Consortium.Disturbances fundamentally alter ecosystem functions, yet predicting their impacts remains a key scientific challenge. While the study of disturbances is ubiquitous across many ecological disciplines, there is no agreed-upon, cross-disciplinary foundation for discussing or quantifying the complexity of disturbances, and no consistent terminology or methodologies exist. This inconsistency presents an increasingly urgent challenge due to accelerating global change and the threat of interacting disturbances that can destabilize ecosystem responses. By harvesting the expertise of an interdisciplinary cohort of contributors spanning 42 institutions across 15 countries, we identified an essential limitation in disturbance ecology: the word ‘disturbance’ is used interchangeably to refer to both the events that cause, and the consequences of, ecological change, despite fundamental distinctions between the two meanings. In response, we developed a generalizable framework of ecosystem disturbances, providing a well-defined lexicon for understanding disturbances across perspectives and scales. The framework results from ideas that resonate across multiple scientific disciplines and provides a baseline standard to compare disturbances across fields. This framework can be supplemented by discipline-specific variables to provide maximum benefit to both inter- and intra-disciplinary research. To support future syntheses and meta-analyses of disturbance research, we also encourage researchers to be explicit in how they define disturbance drivers and impacts, and we recommend minimum reporting standards that are applicable regardless of scale. Finally, we discuss the primary factors we considered when developing a baseline framework and propose four future directions to advance our interdisciplinary understanding of disturbances and their social-ecological impacts: integrating across ecological scales, understanding disturbance interactions, establishing baselines and trajectories, and developing process-based models and ecological forecasting initiatives. Our experience through this process motivates us to encourage the wider scientific community to continue to explore new approaches for leveraging Open Science principles in generating creative and multidisciplinary ideas.This research was supported by the U.S. Department of Energy (DOE), Office of Biological and Environmental Research (BER), as part of Subsurface Biogeochemical Research Program’s Scientific Focus Area (SFA) at the Pacific Northwest National Laboratory (PNNL). PNNL is operated for DOE by Battelle under contract DE-AC06-76RLO 1830

A study of the mechanism of liquid entrainment as affecting the design of dephlegmators, evaporators, absorbers

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