Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Despite hopeful report that fungi help trees weather acid rain, not all species are protected, Cornell forest ecologist warns

19.06.2002


A discovery reported in the latest edition of the journal Nature (June 13, 2002) -- that fungi on the roots of some trees in the Northeastern United States help supply much-needed calcium in forest soils battered by acid rain -- would seem to ease worries about the worrisome form of pollution.



But don’t stop worrying just yet, warns Timothy J. Fahey, the Liberty Hyde Bailey Professor of Natural Resources at Cornell University and a co-author of the report, "Mycorrhizal weathering of apatite as an important calcium source in base-poor forest ecosystems."

"Not all tree species are fortunate enough to be associated with the types of root fungi that supply calcium," he says, pointing to sugar maples, which in some areas have suffered serious declines in recent years.


"And although our findings suggest that trees with the right fungal associations may be able to short-circuit the loss of calcium in the soil, that may not get them around other problems with acidification of soil," he adds. For example, when soil pH is lowered (and acidity rises) more naturally occurring aluminum is available to hinder plant growth. Fahey is co-principal investigator in the soil study sponsored by the National Science Foundation (NSF) at New Hampshire’s Hubbard Brook Experimental Forest.

Also contributing to the Nature report were researchers at the University of Michigan, Syracuse University, the Yale School of Forestry and Environmental Studies, the U.S. Department of Agriculture’s Forest Service and the Institute of Ecosystem System Studies in Millbrook, N.Y.

Although forest scientists have known for more than three decades that acid rain causes the essential plant nutrient calcium to leach from forest soils, the role of the "short-circuiting" fungus was not suspected until about three years ago. That’s when electron-microscopy examination of sand revealed tiny tunnels burrowed through the grains; the mini-miners turned out to be ectomycorrhizal fungi that can penetrate micropores in silicates and take up phosphorus, as well as calcium. Living in symbiotic relationships on some tree roots -- where fungi obtain sugar needed for life processes -- the ectomycorrhizal fungi deliver calcium and phosphorus directly to the trees before the nutrients are lost to acidic soils.

The NSF-sponsored study at Hubbard Brook is testing the long-term result of adding calcium to forested ecosystems to return acid-base ratios to levels that probably existed a century ago, before industrial pollution began to change the chemical landscape of the northeastern United States. The Hubbard Brook researchers were using stable isotope tracing to learn the sources of calcium in plant matter. They found that a significant proportion of calcium in some tree species (particularly conifers, beech and birches) growing in calcium-poor, acidic soil was coming from apatite, a soil mineral mined by fungi on tree roots.

Apatite, pronounced like "appetite," is a calcium phosphate mineral. The trees also were getting some calcium from the better-understood "soil exchange complex," in which calcium is replenished by mineral weathering and atmospheric deposition before being absorbed by roots. But without the beneficial "weathering" of apatite by the ectomycorrhizal root fungi, some trees in acid rain-drenched soils probably would not be getting enough calcium, the researchers reasoned.

Benefits of the fungal association are most pronounced in tree species that can sustain the right kind of mycorrhizae on their roots -- spruce, fir and most other coniferous varieties, as well as certain hardwoods, such as oaks. And a lesser benefit might accrue to trees species with the "wrong" type of root fungi -- including ash, basswood and maples -- if they are growing nearby in mixed-species forests, simply because they are close enough to share calcium mined by other trees’ mycorrhizae, Cornell’s Fahey says.

"But trees trying to grow in the center of a single-species stand, like a sugarbush, could be in trouble," Fahey says, noting that the sugar maple decline in the Northeast has been linked with calcium and magnesium depletion in soils..

And he hopes that anyone who downplays the effects of pollution will not take comfort in the knowledge that obscure fungi are mopping up after acid rain. "There are still numerous deleterious effects of acid rain," Fahey says, "that have nothing to do with mycorrhizae."

Roger Segelken | EurekAlert!
Further information:
http://www.hbrook.sr.unh.edu/hbfound/hbfound.htm

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

Im Focus: Hybrid optics bring color imaging using ultrathin metalenses into focus

For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.

But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...

Im Focus: Stem cell divisions in the adult brain seen for the first time

Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.

The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...

Im Focus: Interference as a new method for cooling quantum devices

Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters

Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Contacting the molecular world through graphene nanoribbons

19.02.2018 | Materials Sciences

When Proteins Shake Hands

19.02.2018 | Materials Sciences

Cells communicate in a dynamic code

19.02.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>