Novel microorganisms play major role in one of nature's most important processes

Researchers have uncovered evidence that recently discovered microorganisms – unseen to the human eye – are playing a major role in helping to support life on Earth.

The scientists believe their findings about a type of microorganism found in soil could lead to a reassessment of current thinking on nitrogen cycling – a process which is vital for all plants and animals.

The studies published in Nature today (August 17) could also yield new insights into the production of greenhouse gases and the pollution of groundwater, and could potentially provide new clues for more efficient and more cost-effective fertilisation processes for farmers.

The researchers from the University of Aberdeen; the University of Bergen, Norway; the Institute of Soil Ecology and the Institute of Geology and Mineralogy, both Germany, and Pennsylvania State University, America studied a group of microbes called Crenarchaea whose existence in soil and seawater was only discovered around 14 years ago.

By carrying out genetic analysis of soil samples, the team discovered evidence that Crenarchaea are responsible for most of the world’s oxidation of ammonia in soil.

The finding turns current thinking on its head – up until now it has been thought that ammonia oxidation was restricted to another type of microbe: bacteria.

Ammonia is produced naturally in the soil by bacteria decomposing dead plants and animals and animal waste.

Ammonia is then converted to nitrite, through a process called ammonia oxidation, and subsequently to nitrate. This process is called nitrification and is a key part of the nitrogen cycle, which sustains living things on Earth.

The ammonia oxidation process – the first step of nitrification – also results in the production of nitrous oxide which is a greenhouse gas.

Nitrates from ammonia oxidation also leach into the groundwater.

In this new study the researchers have discovered that ammonia oxidising Crenarchaea are more abundant than bacteria and, potentially, more important in oxidising ammonia.

Professor Jim Prosser and Post Doctoral Research Fellow Dr Graeme Nicol were the University of Aberdeen collaborators on the research. Professor Prosser said: “The results published in Nature indicate that bacteria are only minor players in ammonia oxidation in soil and that most oxidation is performed by Crenarchaea.

“Our findings show that this group of microorganisms, which was unknown just over a decade ago, may be responsible globally for most of the oxidation of ammonia in soil.”

Ammonia-based fertilisers are added to the soil by farmers to enhance crop production, as nitrogen is a major plant nutrient requirement. However, nitrate, produced by nitrifying microorganisms, is easily washed out of soil, resulting in significant economic losses to the farmer.

Professor Prosser added: “If Crenarchaea are the world’s most efficient ammonia oxidizing microorganism we should be targeting that group of microbes rather than bacteria.

“If we are able to inhibit the workings of this group of microorganisms it could cut down on greenhouse gas emissions, cut down on water pollution and possibly lead to the development of more effective fertilisers for farmers.”

Source: University of Aberdeen

Related stories:

Study reveals function of ubiquitous yet poorly understood microorganisms
Discovered in the late 1970s, archaea are one of the three main branches on the tree of life, with bacteria and eukaryotes such as plants and animals on the other two branches. But scientists are just now gaining a fuller understanding of what archaea do – in an ecological sense – to make a living.
As Andean glacier retreats, tiny life forms swiftly move in, study shows
A University of Colorado at Boulder team working at 16,400 feet in the Peruvian Andes has discovered how barren soils uncovered by retreating glacier ice can swiftly establish a thriving community of microbes, setting the table for lichens, mosses and alpine plants.
Trees kill odors and other emissions from poultry farms
Planting just three rows of trees around poultry farms can cut nuisance emissions of dust, ammonia, and odors from poultry houses and aid in reducing neighbor complaints, according to scientists from the University of Delaware.
Study provides a first look at ammonia volatilized from surface applied urea
The question of how much nitrogen is lost from fertilizer urea when it is applied to the soil surface comes up with growers and fertilizer dealers every season and is the focus of a Montana Agricultural Experiment Station investigation being conducted in northern Montana.


Addressing the 'nitrogen cascade'
While human-caused global climate change has long been a concern for environmental scientists and is a well-known public policy issue, the problem of excessive reactive nitrogen in the environment is little-known beyond a growing circle of environmental scientists who study how the element cycles through the environment and negatively alters local and global ecosystems and potentially harms human health.
Too much nanotechnology may be killing beneficial bacteria
Too much of a good thing could be harmful to the environment. For years, scientists have known about silver’s ability to kill harmful bacteria and, recently, have used this knowledge to create consumer products containing silver nanoparticles. Now, a University of Missouri researcher has found that silver nanoparticles also may destroy benign bacteria that are used to remove ammonia from wastewater treatment systems.
Residents sue over dust from old dump site
Residents of a south Florida community are suing a commercial developer over alleged toxic dust from a former dumping site.
Iowa State researcher studies the sustainability of the bioeconomy
This spring farmers responded to the ethanol industry's demand for grain by increasing their corn acreage by 19 percent over last year, according to U.S. Department of Agriculture estimates.

News discussion:

Space & Earth science news