Airborne Microbial Communities

Project Overview
The air is one of the last unexplored biological habitats on Earth, and little is known about airborne microbial communities (AMCs), which include bacterial, archaeal and fungal inhabitants. The atmosphere serves as a mechanism for microbial dispersal across terrestrial ecosystems, and is a critical factor for global function, yet few studies have examined how changes in altitude impact the composition of AMCs, or how different terrestrial ecosystems influence the atmospheric microbial seedbank. In the proposed work, we will conduct the first rigorous analysis of AMCs at five altitudes above four natural ecosystems in North America. We will use a unique combination of tethered and launched balloon-borne samplers to obtain samples from 2 to 25,000 meters in the atmosphere at three of the four ecosystems. (We will not conduct launched-balloon sampling at Harvard Forest LTER due to the proximity to the Atlantic Ocean and high probability of losing the sampler.) We will investigate how ecosystem type, altitude and seasonality impact the contribution of terrestrial sources to AMCs and provide the first characterization of AMCs at high altitudes above terrestrial ecosystems. By co-locating our sampling with NEON sites, this work will be leveraged by data and infrastructure provided by NEON. In addition, we will explore how anthropogenic activities influence AMC distribution. Some of greatest impacts that humans have on ecosystems are caused by urbanization. Increased impervious surface area, pollutants and heat island effects resulting from urbanization have an overall effect of homogenizing urban ecosystem processes, as compared to pristine sites. We will examine the effect of urbanization on AMCs by collecting samples at three altitudes overlying urban sites located in the same eco-regions as the natural sites. We will use multivariate statistical approaches to determine which biotic and abiotic factors best predict variation in AMCs and examine whether urbanization has a homogenizing effect on the air microbiome, with implications for altered global microbial dispersal.
Investigator Info
Funding agency: 
National Science Foundation
Years active: 
2015 to 2016