Whether it is a single rock being overturned or an entire mountaintop being removed, humans play a continuous role in environmental processes, and vice versa. Human-ecosystem interactions - from the effects of nanomaterials on plant growth to the diversity of insect species on green roofs, and even communities of airborne microbes in hospital buildings - are on the agenda at the Ecological Society of America's 95th Annual Meeting in Pittsburgh, US. Here is just some of the latest research on humans and the environment:
Nanotechnology and the environment
Silver nanoparticles are being increasingly used in consumer and medical products for their antimicrobial properties. However, use of these products results in the release of nanoparticles into the environment through wastewater effluent and biosolids, or treated wastewater byproducts. Benjamin Colman from Duke University and colleagues analysed the potential effects of exposure to these particles on microbial and plant activity, growth and abundance.
Their findings revealed that silver nanoparticles altered root growth and plant physiology, and the abundance, composition and activity of microbial communities. Specifically in plants, roots near the soil surface were more abundant, though biomass of one of the five tested plant species decreased by 22%. In addition, microbial abundance decreased, the species of bacteria present changed and microbial enzyme activities were reduced by as much as 34%.
Insect diversity of green roofs
Green roofs have been gaining popularity due to their natural cooling and storm water management benefits, as well as the opportunity to provide habitat for insects and birds. Researchers Scott MacIvor and Jeremy Lundholm from Saint Mary's University in Halifax, Nova Scotia discovered the biodiversity of green roofs is more abundant than previously thought.
The scientists report that insect richness and abundance on a green roof is no different from that of nearby urban habitats. The researchers found that, in addition to large numbers of several unique species on the green roofs, these roofs served as a refuge for a number of uncommon species.
"As the rate of green roof installation increases, optimising these constructed habitats for long-term support of insect species will not only improve services such as pollination, pest control and decomposition, but also aesthetic and educational opportunities in 'species-poor' cities," reads their report.
Invasion ecology of the human body
What makes someone susceptible to an infectious disease? According to research presented in a symposium at ESA's Annual Meeting, the resilience of naturally-occurring microbes in the human body plays a large role in susceptibility. That is, the diversity and abundance of normal microbial communities in the human body can help fight off pathogen invasions. With this in mind, ecological and biomedical scientists will merge their research to create a comprehensive analysis of human infectious disease and discuss opportunities for prevention.
In one of the presentations, for example, Steven Kembel and colleagues from the University of Oregon discuss how building design influences airborne microbes in a hospital environment. The study revealed that bacteria are abundant in airborne microbial communities, regardless of the type of ventilation a hospital uses. However, the diversity and composition of these communities, they found, differed between mechanically- and naturally-ventilated rooms. They discovered that several types of bacteria with effects on human health were more common in mechanically-ventilated rooms than rooms with open windows and no fans. The scientists will address the implications of their findings for hospital ventilation planning. - (EurekAlert!, August 2010)