Mission Statement
BROADN seeks to advance biologic discovery by assembling transdisciplinary expertise to study the aerobiome in relationship to the factors that shape it, and to investigate airborne biotic content, both near the Earth’s surface and into the lower atmosphere.
We will integrate across disciplines to develop strategies, technologies, datasets and analytical tools for the scientific community studying microbes in the air and their implications for human, animal, and environmental health. We will train and inspire students in an interdisciplinary, collaborative and innovative environment, develop an aggressive community outreach program, and embrace diversity in expertise, experience, and approach.
Current BROADN Projects
BROADN research is exploring the dynamics of the aerobiome through the integration of three intersecting research goals: Establish Standards for Aerobiome Sampling and Analysis; Develop a Predictive Model of Aerobiome Composition; and Develop a Mechanistic Model for Microbe Survival.
Goal 1 Projects
Sampling Methods, Limits of Detection, and Pipeline Development
Goal 2 Projects
Links Between the Aerobiome and Terrestrial Microbiomes
Goal 3 Projects
Traits Supporting Lofting and Survival
Project Overviews
Performance evaluation of bioaerosol samplers in an environmentally controlled chamber
Lead Investigator: Marina Neito-Caballero
Co-Investigators: Sonia Kreidenweis, Kevin Barry, Mark Hernandez, Kristen Rugh, Emily Kraus
Project Summary
Our goal is to fill in gaps in our understanding of how well these samplers work in different conditions, which will help standardize bioaerosol sampling techniques.
The results will help researchers choose the best samplers for their studies. We plan to publish our findings so that future research on bioaerosols can be more reliable and comparable across studies.
Performance evaluation of viral RNA integrity retrieved from bioaerosol samplers
Lead Investigator: Angela Bosco-Lauth
Co-Investigators: Sonia Kreidenweis, Mark Hernandez, Marina Nieto-Caballero, Kevin Barry, Jeffrey Morano
Project Overview
Detecting viruses and RNA using high-flow aerosol sampling can be challenging because the strong airflow may break the RNA into pieces that are too small for testing. A study on one RNA virus showed that different methods, like cyclones and other low-flow water-based condensers, can detect the virus, but longer sampling times might dry it out or harm it. We don’t know how strong airflow affects viral RNA when using high volume dry samplers, like the SASS.
We will study the impact of high-flow sampling on different types of viruses, including enveloped viruses, which have a protective outer layer, and non-enveloped viruses, which do not have this layer and are usually tougher against harsh conditions. This research will help us understand how well high-volume aerosol samplers can collect and keep viral RNA intact.
Performance evaluation of drone-mounted mini-SASS high-volume aerosol sampler
Lead Investigator: Sheryl Magzamen
Co-Investigators: Peter Kessinger, Angela Bosco-Lauth, Mark Hernandez
Project Overview
The SASS 3100 aerosol sampler, which collects airborne particles, has been adapted to work with drones. However, the current model is too heavy, reducing flight time. Research International, the manufacturer, has created a lighter version of the sampler, which will allow drones to fly longer and collect data. We’re working with them to test both the heavy and light samplers.
The project compares the two samplers in different conditions: in a chamber, at ground level, and in flight. In the chamber, we’ll release a known amount of particles to see how efficiently the samplers collect them. In field tests, samplers will be compared at ground level and 12 meters in the air using two drones. We’ll compare the DNA collected by both samplers to measure performance. This will help us understand if the lighter sampler works as well as the heavier one in different conditions.
HICCUP - High-flow-rate and improved condensation collection for bioaerosols using pre-concentration
Lead Investigator: Shantanu Jathar
Co-Investigators: Mark Hernandez, Jane Stewart, Sonia Kreidenweis, Marina Nieto-Caballero, Angela Bosco-Lauth, Drew Jones
Project Overview
Bioaerosols, which are tiny biological particles in the air, can be collected efficiently using water condensation samplers like BioSpot-VIVAS and BioSpot-GEM. These samplers are better than filter-based ones because they avoid problems like drying out and losing the particles. However, they have a low collection flow rate, which means they might not work well in areas where there are few bioaerosols.
To improve this, we plan to use a device called a virtual impactor, which can concentrate the air sample before it reaches the sampler. We will design and build this virtual impactor based on earlier research. We will test how well it works using different aerosol models in a controlled chamber. We believe that this setup will allow us to collect 10 to 20 times more bioaerosols in the same amount of time when used in conjunction with samplers like the BioSpot-VIVAS and BioSpot-GEM.
Characterizing fungal spore emissions source strength and conditions in a controlled chamber environment
Lead Investigator: Angela Bosco-Lauth
Co-Investigators: Jane Stewart, Mark Hernandez, Jeffrey Morano, Kevin Barry
Project Overview
Detecting plant pathogens that spread through the air can be tricky with standard equipment. To tackle this, we will use a small growth chamber to study how infected Ribes plants release spores from the fungus Cronartium ribicola, which causes white pine blister rust. We will control the conditions inside the chamber, such as temperature, humidity, and light.
Infected Ribes plants will be placed in the chamber with settling plates at different heights, and we will use two types of air samplers to measure the number of spores and see how well each sampler works. We will repeat this process with infected white pine plants, which have a different stage of the fungus.
The results will help us understand how well our sampling methods work for different life stages of the fungus and will give us insight into how infected plants release spores.
Developing surface-atmosphere flux measurements for total DNA and other bioaerosol markers
Lead Investigator: Delphine Farmer
Co-Investigators: Sonia Kreidenweis, Jay Ham, Lily Jones
Project Overview
This project focuses on measuring bioaerosol fluxes over the grasslands. A bioaerosol is a tiny particle in the air that comes from living things, like plants, animals, or bacteria and their fluxes are how much of those tiny living particles, like pollen or germs, move from one place to another in the air.Understanding this movement is important because these particles can affect health, weather, and ecosystems.
In our study, we will use a technique called the flux gradient approach to measure how much DNA from these particles is in the air. We will collect samples on filters from different heights while also measuring heat flow in the area. This will help us figure out where the bioaerosols come from—whether they are from nearby sources or carried in from far away. We will also take measurements over several days and seasons to understand how weather affects these movements. This research will help us understand the factors that influence bioaerosol movement in grasslands.
Ice nucleating particle emissions by raindrop impact
Lead Investigator: Claudia Mignani
Co-Investigators: Sonia Kreidenweis, Marina Nieto-Caballero, et al.
Project Overview
Ice-nucleating particles (INPs) are tiny particles in the atmosphere that help ice form in clouds, affecting the water cycle and climate. However, we don’t fully understand where these particles come from or how they change over time and in different places.
In our study, we looked at how INPs are linked to rainfall at a grassland site in Colorado. We found that the amount of INPs in the air increased with the energy and amount of rainfall. This suggests that raindrops and hailstones may help release INPs into the air. We also found that local plants are the main source of INPs released during precipitation.
If these INPs rise into clouds, they could affect how much ice forms in the clouds and might even trigger more rainfall. This process could create a cycle where clouds, aerosols, and precipitation influence each other, affecting weather patterns.
Drivers of aerobiome composition and diversity in central grasslands
Lead Investigator: Pankaj Trivedi
Co-Investigators: Jan Leach, Marina Nieto-Caballero, Avinash Dhar, Sonia Kreidenweis, Kris Otto
Project Overview
The aerobiome refers to tiny microorganisms that live in the air. These microbes play important roles in ecosystems, disease outbreaks, and possibly even the Earth’s water cycle. While we know a lot about the microbiomes in humans, animals, plants, and soil, we don’t yet fully understand the aerobiome.
In our study, we looked at the diversity and types of microbes in the air of grasslands during Fall 2022 and Spring 2023. We also studied the bacteria and fungi found in the soil and on plants. We wanted to understand how the air microbes interact with the soil and plant microbes, and how things like weather and soil conditions affect the air microbes.
We are finding that the microbes in the air are just as diverse and complex as those in soil and plants. Some microbes in the air seem to stay in certain areas (called “core microbiota”). Our research showed that soil bacteria have stronger connections with air microbes, while air fungi are more connected to plant microbes. Understanding these interactions is important for predicting how the aerobiome works and how it might change in the future.
Structure and function of grassland aerobiome from Spring 2023 CEPR Campaign
Lead Investigator: Pankaj Trivedi
Co-Investigators: Jan Leach, Marina Nieto-Caballero, Avinash Dhar, Rocio Rodriguez de las Llagas
Project Overview
This study uses advanced genetic techniques to explore the aerobiome, or microbiome of the air. Shotgun metagenomics is a method used to study the genetic makeup of all the microorganisms in a sample, including bacteria, viruses, and fungi. This technique helps scientists learn about the diversity, functions, and survival strategies of microbes.
In our project, we will analyze 36-40 samples collected during a 2023 campaign in the Colorado grassland aerobiome. We want to understand how things like humidity, sunlight, and altitude affect the diversity and functions of these air microbes. Our goal is to identify the main characteristics of the aerobiome and how environmental factors drive changes in its composition. This research will help us better understand how microbes in the air can affect the environment and how diseases might spread through the atmosphere. By predicting the aerobiome’s composition and functions, we aim to advance knowledge critical for understanding ecosystem health and environmental impacts on microbial life.
Changes in aerobiome communities with different habitat types over time (using two sampling towers)
Lead Investigator: Jane Stewart
Co-Investigators: Ashley Miller, Carolyn Cornell, Zaid Abdo, Caley Little, Marina Nieto-Caballero, Kelly Burns (FS), Kris Otto, Jessica Metcalf
Project Overview
This project explores how airborne microbial communities change in different environments and at different times. The aerobiome affects plant and human health, and factors like land type, height above ground, season, and time of day all influence its composition. Although past studies have looked at aerobiomes in forests and grasslands separately, they rarely compare these environments at various heights or times of day.
In this study, air samples were taken from both grassland and forest areas in Colorado during spring, summer, and fall of 2023. Weather data like temperature and wind speed was recorded to help analyze how these conditions might affect microbial communities. By studying how microbial communities vary based on location, height, and time, we hope to understand the movement of airborne microbes, including those linked to diseases.
Sources and patterns of the air microbiome in a fragmented landscape
Lead Investigator: Noah Fierer
Co-Investigators: Claire Winfrey, Julian Resasco, Jane Stewart
Project Overview
We used plant, soil and air samples from well-studied habitat plots in South Carolina to investigate: (1) Does vegetation type affect the variety of airborne bacteria and fungi nearby? (2) What are the main sources of microbes in the air close to the ground? (3) What traits help bacteria and fungi spread through the air?
Findings showed that vegetation type has little impact on the types of airborne microbes. However, leaves were found to release more bacteria and fungi into the air than soil does. Interestingly, not all microbes are equally suited to spreading through the air. Bacteria with the ability to form spores and fungi with smaller spores were more likely to become airborne than other types found on leaves. Results from these studies will be submitted for publication in late 2024.
Aerobiomes of America
Lead Investigator: Noah Fierer
Co-Investigators: Sarah Gering, Marina Neito-Caballero, Scott Copeland, Sonia Kreidenweis
Project Overview
The IMPROVE (Interagency Monitoring of Protected Visual Environments) network is a program in the United States that monitors air quality and environmental conditions in national parks and wilderness areas. In addition to air quality measurements, the network has been expanded to study airborne microbes, including fungi and pollen, as part of the broader effort to understand the composition of the “aerobiome” (microorganisms in the air). We are using archived samples from 7 IMPROVE sites to study the fungal aerobiome—the variety and amount of fungi in the air. We will analyze the types and amounts of fungi in these samples to understand patterns of fungal microbes in the air across the country. We will also explore how local conditions, like weather and air mass movement, affect these patterns and how events like dust storms impact the fungi in the air.
We’re especially interested in tracking the spread of fungal allergens (substances that can cause allergic reactions). By looking at how these allergens change with the seasons, soil conditions, and weather, we hope to understand the health risks to people who are exposed to them. We’re also expanding our research to look at plant DNA in the same samples, which will allow us to study pollen allergens and learn more about how plants contribute to the airborne microbes across the US.
Identifying Microbial Sources of the Respiratory Microbiome in the Ornate Box Turtle
Lead Investigator: Fran Sandmeier
Co-Investigators: Victoria (Tori) Martinez
Project Overview
Ornate Box Turtles live in western Colorado. These turtles are ectotherms, meaning they rely on outside heat to regulate their body temperature. In winter, they burrow underground and live in short grassland prairies. Like many animals, they have a complex microbiome (the community of microorganisms) in their bodies, including the mouth, nose, and upper respiratory system. This microbiome is important for their health but is not well understood.
Our research focused on studying the types and amounts of microorganisms in the air, soil, and turtles’ bodies. We also tested how well air filters (liquid and dry) capture these microorganisms. By comparing the microorganisms in different samples, we found significant differences in microbial composition. We discovered that the turtles’ respiratory microbes were more similar to those in the air and surface soil than to those in the soil of their winter burrows.
This study highlights the role of the environment in shaping the microbiome of turtles, especially in their upper respiratory tract, and shows how microbes can be passed between turtles and their surroundings.
Genetic Basis of Ultraviolet Radiation Tolerance in Airborne Bacterial Isolates
Lead Investigator: Amaya Garcia-Costas
Co-Investigators: Avinash Dhar, Gatel (CSU-P)
Project Overview
This study investigates how certain bacteria from the aerobiome resist UV-B radiation, a harmful form of sunlight. Six strains from diverse bacterial groups, identified in a previous study, show remarkable survival after UV-B exposure, but the reasons behind this resilience are unknown.
We will analyze the DNA of these bacteria to identify genes that help them withstand environmental stress, particularly UV-B radiation. To understand their full response, we’ll also study changes in their RNA, proteins, and metabolites after UV-B exposure. Since UV-B light can increase toxic reactive oxygen species (ROS), we’ll test whether these bacteria have efficient systems to neutralize ROS, which might play a role in their resistance.
By examining the genetic, physiological, and biochemical strategies these bacteria use, we aim to uncover both unique and shared mechanisms of UV-B resistance. These insights could deepen our understanding of how microbes survive in harsh atmospheric conditions and their potential roles in ecosystem resilience.
Characterizing Sub-lethal Responses of Airborne Bacteria to UV Irradiation at Different RH Levels
Lead Investigator: Amaya Garcia-Costas
Co-Investigators: Mark Hernandez, Emily Kraus, Avinash Dhar, Gatel (CSU-P)
Project Overview
This study examines whether UV-B resistance in aerobiome bacteria, measured in traditional lab conditions (liquid and solid media), holds true when the bacteria are aerosolized—mimicking real-world airborne states. Two UV-B resistant strains from the ARDEC pilot study, along with the highly resilient Deinococcus radiodurans as a control, will be tested.
The bacteria will be aerosolized in chambers under controlled UV exposure. Their survival will be assessed using methods like cell counts, qPCR, and analysis of DNA damage. Additionally, we will study their RNA to identify changes in gene activity, comparing how aerosolized bacteria respond to UV light versus those in liquid culture.
This research will clarify whether bacteria’s UV resistance in lab studies translates to airborne conditions. We expect the selected strains to retain their resistance, providing insights into their adaptability. These findings will help determine the reliability of lab-based data for understanding bacterial behavior in atmospheric environments, improving our ability to study and predict aerobiome dynamics.
Deciphering the Roles of Rhamnolipids in Bacterial Aerosolization and Atmospheric Stress Tolerance
Lead Investigator: Brad Borlee
Co-Investigators: Sam Golon, Eleah Flockhart, Beth Hayes, Angela Bosco-Lauth, Pankaj Trivedi, Sonia Kreidenweis, Kevin Barry, Emily Kraus, Mark Hernandez
Project Overview
This study looks at how rhamnolipids—special molecules made by bacteria—help them get into the air and survive tough conditions. These molecules are well-studied in Pseudomonas aeruginosa, a common bacterium in the aerobiome, where they help bacteria spread, compete, and survive in different environments.
Scientists will create bacteria strains that produce different amounts of rhamnolipids to see how these molecules help bacteria become airborne. They will also develop tools to measure how well bacteria form aerosols. Rhamnolipids are known to work with other molecules that protect bacteria from things like UV light and harmful chemicals in the air.
The study will test these bacteria to see how well they survive stressful conditions and analyze their genes to learn how they adapt when becoming airborne. This research will help us understand how bacteria survive in the atmosphere and how they spread through the air.
Unraveling the Roles of Ice Nucleation Proteins in Bacterial Survival and Fitness During Aerosolization
Lead Investigator: Brad Borlee
Co-Investigators: Eleah Flockhart, Mark Hernandez, Emily Kraus, Kevin Barry, Jeff Buxton
Project Overview
This study explores how certain bacteria survive in the air by producing proteins that help them form ice at higher temperatures, a process known as ice nucleation. Some bacteria can make Ice Nucleation Proteins (INPs) that help them survive in tough conditions, like freezing temperatures or dry air. However, scientists don’t know much about how these proteins help bacteria survive when they are airborne.
To study this, researchers will create mutant strains of two bacteria, Pantoea agglomerans and Pseudomonas syringae, that do not produce INPs. They will delete parts of the gene that makes these proteins, including the section that is responsible for creating ice. The researchers will test how these mutant bacteria perform in different conditions, like freezing, UV light exposure, and dryness.
They will also make special antibodies that can detect the INP proteins to see where and how they work inside the bacteria. Additionally, the Pantoea bacteria will be aerosolized in a controlled environment, and the scientists will study which genes are turned on or off when the bacteria are released into the air.
This research will help scientists understand how ice nucleation proteins help bacteria survive in the atmosphere and how they might affect plant health and ecosystems.
Proteomics of the Aerobiome
Lead Investigator: Ken Reardon
Co-Investigator: Sei Park
Project Overview
This project explores the proteins of aerobiome bacteria to better understand their real-time activity and how they adapt to harsh atmospheric conditions. Unlike genomics and transcriptomics, which reveal potential functions, proteomics directly shows what cells are doing at the moment they are sampled. Despite its importance, few proteomic studies have focused on aerobiome isolates, and none have analyzed entire aerobiome samples.
We will study proteins from bacteria involved in related BROADN projects, such as those examining UV resistance. Additionally, we aim to refine methods for direct proteomic analysis of aerobiome samples, addressing challenges beyond small sample sizes. We hypothesize that UV exposure and other atmospheric conditions alter bacterial proteins, requiring innovative approaches to study them.
To test this, we will analyze aerosolized samples exposed to controlled conditions, replicating atmospheric stressors. This research will provide insights into how aerobiome microbes respond to environmental pressures, paving the way for deeper understanding of their roles in ecosystems and resilience to changing conditions.
Exploring a novel resource to identify and characterize aerobiome survival genes (Bacillus mGWAS)
Lead Investigator: Jan Leach
Co-Investigators: Pankaj Trivedi, Amaya Garcia-Costas, Brad Borlee, Luna
Project Overview
Air is a tough place for microbes to survive, and we know much less about how they live in the air compared to other environments. Bacteria play important roles in chemical processes and can affect the health of plants and animals, so it’s crucial to understand how they move, persist, and function in the air.
One group of bacteria that we commonly find in the air is called Bacillus. We will use a population of slightly different Bacillus, called a microbial genome-wide association study (mGWAS) population, to look for special traits like their ability to tolerate UV light, resist antibiotics, and produce attachments or protective films. This research will help us learn more about how these bacteria thrive in the air.
Delineate the Known Diversity of Bacteria Capable of Spore Formation
Lead Investigator: Noah Fierer
Co-Investigators: Claire Winfrey, Pankaj Trivedi
Project Overview
Claire Winfrey is collaborating with Noah Fierer and Pankaj Trivedi on a project to delineate the known diversity of bacteria capable of spore formation. This project is relevant to BROADN given that the ability to form spores resistant to environmental stressors is a key mechanism for survival/dispersal in the atmosphere, yet the known the diversity of bacterial spore formers remains uncharacterized. The data for this project are currently being collected and analyses are underway.
Metagenomic Shotgun Sequencing of Turtle Nasal Lavage, Soil, and Air Samples
Lead Investigator: Erin Doyle
Co-Investigators: Fran Sandmeier, Manzanares
Project Overview
This project focuses on finding and studying bacteria and phages in turtle and environmental samples. A bacterial phage is a tiny virus that specifically infects and kills bacteria, using them to make more copies of itself.
Studying phages is important because they can help us understand and control bacterial infections. Additionally, they play a key role in ecosystems by regulating bacterial populations and contributing to nutrient cycling. We used advanced DNA sequencing and developed a novel pipeline to identify phages. Our results show that phages were present in all samples, with turtle samples having more phages than air samples.