Hidden giants in forest soils

Only a fraction of the microbes residing in, on and around soils have been identified through efforts to understand their contributions to global nutrient cycles. Soils are also home to countless viruses that can infect microbes, impacting their ability to regulate these global cycles. In Nature Communications, giant virus genomes have been discovered for the first time in a forest soil ecosystem by researchers from the DOE Joint Genome Institute and the University of Massachusetts-Amherst.

Characterizing the diversity of microbial cells in a handful of soil is so complex it was considered impossible. To date, only a small fraction of the microbes residing in, on and around soils have been identified as part of efforts to understand their contributions to the global carbon cycle, and to other nutrient cycles. Soils are also home to countless viruses that can infect microbes, impacting their ability to regulate these global cycles.

Reported November 19, 2018, in Nature Communications, giant virus genomes have been discovered for the first time in a forest soil ecosystem by researchers from the U.S. Department of Energy (DOE) Joint Genome Institute (JGI), a DOE Office of Science User Facility, and the University of Massachusetts-Amherst (UMass Amherst). As the name implies, giant viruses are characterized by disproportionately large genomes and virions that house the viruses’ genetic material. They have been frequently found within protists and algae, and thus they are believed to have a significant impact on their hosts’ population dynamics and the planet’s biogeochemical cycles.

Source: Hidden giants in forest soils – EurekAlert, 2018-11-19

Part of the Answer to Climate Change May Be America’s Trees and Dirt, Scientists Say

By Brad Plumer
A new study found that the United States could store enough carbon in natural landscapes to offset all the cars and trucks on the road.

When people think of potential solutions to global warming, they tend to visualize technologies like solar panels or electric cars. A new study published on Wednesday, however, found that better management of forests, grasslands and soils in the United States could offset as much as 21 percent of the country’s annual greenhouse gas emissions.

At the high end of the projections, that would be roughly equivalent to taking every single car and truck in the country off the road.

The paper, published in the journal Science Advances, identified a number of promising strategies, like replanting trees on degraded lands, changing logging practices to better protect existing forests and sequestering more carbon in farmland soils through new agricultural techniques.

“We’re not saying these strategies are a substitute for getting to zero-carbon energy; we still need to do that too,” said Joseph E. Fargione, a scientist at the Nature Conservancy and lead author of the study. “But we think that natural climate solutions generally get overlooked. And we found a lot of opportunities here to help mitigate climate change.”

Source: Part of the Answer to Climate Change May Be America’s Trees and Dirt, Scientists Say – New York Times, 2018-11-14

Soil fungi help tree seedlings survive, influence forest diversity

A new paper published Jan. 13 in Science reveals that the relationship between soil fungi and tree seedlings is more complicated than previously known. The paper was co-written by Ylva Lekberg, an assistant professor of soil community ecology at the University of Montana.

Lekberg and her collaborators studied 55 species and 550 populations of North American trees. Scientists have long known that plants and soil biota can regulate one another, but the new findings highlight the complexity of the feedback loop.

“Fungi differ in their ability to protect tree seedlings from pathogens, and this has implications for seedling recruitment and therefore forest community patterns,” Lekberg said.

Most plant roots are colonized by mycorrhizal fungi, but tree species associate with different fungal groups. The researchers showed that ectomycorrhizal fungi that form a thick sheet around root tips are better able to protect trees from pathogens than arbuscular mycorrhizal fungi.

Thus, while ectomycorrhizal tree seedlings actually prefer growing next to parent trees, arbuscular mycorrhizal tree seedlings can only establish outside the control of parents’ enemies. This can have consequences for how temperate forests are structured and their overall diversity.

Source: Soil fungi help tree seedlings survive, influence forest diversity — ScienceDaily, 2017-01-13