Fungi wake & feed bacteria in dry and nutrient poor habitats.

59 Degrees

Researchers closely examined the transport of water, substrates and nutrients through the microscopically small hyphae of fungi. They grew the fungi on a culture medium of water, glucose and nitrogen-containing nutrients. The fungal hyphae had to pass through a dry, nutrient-free zone in order to grow through into a new area containing the culture medium. The inhospitable transition zone contained spores of the common soil bacterium Bacillus subtilis. Spores are inactive stages of Bacillus that form when there is insufficient water, food and nutrients available for bacterial growth. The bacteria go into a kind of dormant stage, from which they only awake once the environmental conditions are more favourable for living again. As the fungal hyphae grew through the dry zone, the bacterial spores germinated and they noticed clear microbial activity.

The researchers then ‘labelled’ the water, glucose and nitrogen-containing nutrients in the culture medium in advance with stable isotopes. If these substances were transferred from the fungus to the bacteria, they could be detected using the isotopic marker.

They found stable isotopes of the labelled water, glucose and nitrogen-containing nutrients in the cell mass of the bacteria — which could only have come from the fungi.

Fungi awake bacteria from their slumber

Leaf particles cause nitrous oxide hotspots in large pore soils

“The leaf particles act as tiny sponges in soil, soaking up water from large pores to create a micro-habitat perfect for the bacteria that produce nitrous oxide.”

Not as much N2O is produced in areas where smaller pores are present. Small pores, such as in clay soils, hold water more tightly so that it can’t be soaked up by the leaf particles. Without additional moisture, the bacteria aren’t able to produce as much nitrous oxide. Small pores also make it harder for the gas produced to leave the soil before being consumed by other bacteria.

Every time you till, what are you creating? Large pores.

Decomposing leaves are a surprising source of greenhouse gases | MSUToday | Michigan State University

The Sea Monster At The Bottom Of The Carbon Food Chain

The ocean sequesters massive amounts of carbon in the form of “dissolved organic matter,” and new research explains how an ancient group of cells in the dark ocean wrings the last bit of energy from carbon molecules resistant to breakdown.

A look at genomes from SAR202 bacterioplankton found oxidative enzymes and other important families of enzymes that indicate SAR202 may facilitate the last stages of breakdown before the dissolved oxygen matter, or DOM, reaches a “refractory” state that fends off further decomposition.

Zach Landry, an OSU graduate student and first author of the study, named SAR202 “Monstromaria” from the Latin term for “sea monster.”

Study illuminates fate of marine carbon in last steps toward sequestration| Oregon State University

SAR202 Genomes from the Dark Ocean Predict Pathways for the Oxidation of Recalcitrant Dissolved Organic Matter

Bonus:

Scientists begin to unlock secrets of deep ocean color from organic matter | UMCES

For the first time, researchers have shown that cultured picocyanobacteria, Synechococcus and Prochlorococcus, found in the open ocean release fluorescent components that closely match these typical fluorescent signals found in oceanic environments.

“Two genus of picocyanobacteria – Synechococus and Prochlorocccos – are the most abundant carbon fixers in the ocean.” said Chen. His lab maintains a collection of marine cyanobacteria and cyanoviruses. Some of these isolates were used in this study.

“When you sail on the blue ocean, a lot of picocyanbacteria are working there,” said Gonsior.” They turn carbon dioxide into organic carbon and are likely responsible for some of the deep ocean color coming from organic matter.”

Microbes measure ecological restoration success

The researchers used next generation sequencing of the DNA in soil from samples taken across the site that had a range of plantings between six and 10 years old.

The technique – high-throughput amplicon sequencing of environmental DNA (eDNA), otherwise known as eDNA metabarcoding – identifies and quantifies the different species of bacteria in a sample.

The researchers – students Nick Gellie and Jacob Mills, Dr Martin Breed and Professor Lowe – analysed soil samples at the restoration site at Mt Bold Reservoir in the Adelaide Hills, South Australia, and compared them with neighbouring wilderness areas as ‘reference sites’.

“We showed that the bacterial community of an old field which had been grazed for over 100 years had recovered to a state similar to the natural habitat following native plant revegetation – an amazing success story,” says Dr Breed, Research Fellow in the Environment Institute.

“A dramatic change in the bacterial community were observed after just eight years of revegetation. The bacterial communities in younger restoration sites were more similar to cleared sites, and older sites were more similar to the remnant patches of woodland.”

Revegetation rewilds the soil bacterial microbiome of an old field – Gellie – 2017 – Molecular Ecology – Wiley Online Library

Plant Species Diversity Improves Soil Ecosystems. [Rant]

Plant species diversity doesn’t improve soil

The above quote was left as a reply to a comment I’d left on a big ag research and education industry video talking about cover crops ages ago. It still irks me that these people are so ignorant.

Today I read the following study on plant species diversity’s impact on soil ecosystems, albeit in a conservation and restoration context that ends up restoring degraded agricultural lands these people create:

Restoring and managing for more diverse plant communities can improve recovery of belowground biology and functioning in predictable ways. Specifically, we found greater accumulation of roots, more predictable recovery of soil microorganisms (bacteria and fungal biomass), more rapid improvement in soil structure (less compaction), and less nitrogen available for loss from the system  in prairie restored and managed for high plant diversity (>30 species) relative to the low diversity (<10 species) grassland plantings.  Thus, the hypothesis that biodiversity promotes ecosystem functioning is relevant to large-scale conservation and restoration practices on the landscape.

Restoration and management for plant diversity enhances the rate of belowground ecosystem recovery

 

Small Molecule Could Have Big Future in Food Security

Crops all over the world are susceptible to infection by fungi of various Aspergillus species, a fungus that produces secondary metabolites known as aflatoxins. These compounds have been implicated in stunting children’s growth, increasing the risk for liver cancer, and making people more susceptible to diseases such as HIV and malaria.

“Aflatoxin is one of the most potent toxins on the planet,” Schmidt said. “Usually it won’t kill a person outright, but it can make you very sick.”

Schmidt and her team set out to study whether a naturally occurring biological mechanism called RNA interference could be used as a weapon against the Aspergillus toxin.

The modified corn plants carry a genetic blueprint for small RNA molecules, each only about 20 base pairs long, only in the edible kernels, not the whole plant.

“The corn is constantly producing that RNA during the entire development of the kernel,” Schmidt explained. “When the kernels come in contact with the fungus, the RNA moves over into the fungus.”

Once inside the fungal cells, the hairpin-shaped RNA molecules pair up with corresponding target sequences of the fungus’ own RNA that code for an enzyme needed for toxin production, in a process called RNA interference. This causes the toxin production to shut down, but does not in any other way impact the fungus, which continues to grow and live on the corn, albeit harmlessly.

Small Molecule Could Have Big Future in Food Security

40 Years of Organic Green Manure for the Win

A new study finds:

  • Organic Green Manure and Organic Animal Manure treatments increased cumulative water infiltration by about 10 times compared with the conventional farming treatment
  • Soil aggregates increased by 50% with the Organic Green Manure and by 30% with the Organic Animal Manure treatments in the upper 15-cm depth
  • At the same depth, bulk density was 3% lower under organic practices than in the conventional farming treatment, suggesting that organic farming reduces the soil’s susceptibility to compaction.

Organic Farming and Soil Physical Properties: An Assessment after 40 Years

Continuous Monocropping.

A new study using a LARGE dataset has found for corn and soybean:

  • Analysis of 748,374 yield records showed a 4.3% yield penalty for continuous corn.
  • Corn yield penalties were more severe in areas with low moisture and low yields.
  • Continuous soybean showed a 10.3% yield penalty, worse in low-yielding years.
  • Corn yield penalties grew with up to 3 yr of continuous cropping, but not more.
  • Soybean penalties increased monotonically with number of years continuously cropped.

Continuous Corn and Soybean Yield Penalties across Hundreds of Thousands of Fields