In the new study, the team, including a group of Penn State undergraduates led by graduate student Boya Xiong, packed the sticky sand into filter columns about 1 cm in diameter and 5-10 cm high, and testing the columns with extract from different amounts of seed to optimize performance. In experiments with 1-µm-diameter polystyrene particles, which have about the same size and charge as bacteria, they found that the sticky sand caught 99.99% of particles, compared with 13.55% for sand alone. The sticky sand also removed 108 viable E. coli cells per milliliter. They estimate that a household-scale filter 1 meter tall and 5 cm in diameter that provides 10 L of water per day would require 0.2 kg of seeds per year, whereas a Moringa tree produces about 480 kg of seeds per year.
Tropical tree seeds provide sustainable water filtration | Chemical & Engineering News
Do Bacteria Live On Meteorites?? | SimplyScience by Kristie Tanner
Kristie summaries a paper that can be found here
Much more interesting than I thought it would be. The iron and sulphur makes me think about the amount of energy those elements provide to form reactions that sustain life(scroll down for pictures), and how differing amounts of those elements may influence the colonization.
I’m also reminded of the sea monster at the bottom of the carbon food chain where there’s little oxygen and energy is scarce.
To the other extreme where oxygen is rich and where historically moisture rich microbes respire excess carbon from soils.
Why So Many Meteorites Come From The Same Place
Bacterial cells in carbon-rich media (purple and blue) grow twice as big as those in carbon-poor media (green). New research shows they can grow big, however, only if they can make fats with the carbon.
Fat (lipids) limits how big bacterial cells can be. “If you prevent cells from making fat, they’re smaller, and if you give them extra fat or allow them to make more fat, they get bigger,” said Levin, professor of biology in Arts & Sciences. “Fat makes cells fat.”
“If we hit the cells with an antibiotic that targets fatty-acid synthesis, we really saw a significant drop in cell size” Vadia said.
Also, by turning up FadR, a transcription factor that activates expression of the fatty-acid synthesis genes, the cells got bigger.
“It doesn’t seem to matter what the lipids are, really,” Levin said, “provided you have enough of them. We found we could give the cells oleic acid, a fat found in avocados and olive oil, to supplement diminished fatty-acid synthesis and as long as the added fatty acid got into the membrane, the cells could recover.”
A little place for my stuff | EurekAlert! Science News
Hydrogenation: transform liquid oil into solid fat
Olive Oil Did WHAT to my Triglycerides??!!?? (Pt 2)
Comments and Questions 6 20 2017
My only experience with weed mat, was pulling one up, and finding stinky dead earth beneath
Now it sounds like this person’s plastic weed mat caused the soil below it to turn anaerobic due to either a lack of air penetrating the mat or retaining too much moisture which then excluded the air from entering the soil. When this happens the soil begins to anaerobically digest and produce alcohols, phenols, and gasses such as methane, the scent of sewer gas.
Not ideal plant growing conditions!
However there can be benefits when using plastic weed mat in the right conditions that does let air and water through, as the mat can help keep the soil moist, especially in drier regions. Weed mats can also warm or cool the soil depending on how much sunlight they absorb or reflect. They can also help prevent erosion. But the main reason people use it, is because the mats also reduce weed competition for plants planted into or near the weed mat. Reduced competition for water, sunlight, and for nutrients.
However the biggest problem with plastic weed mat when growing and assuming the correct mat was chosen for the conditions, is that if left on for extended periods, the soil often tends to breed plant pathogens. This happens when soils are not amended with a high carbon source such as plant leaf litter, plant exudates, or an organic mulch.
In soils that are kept moist and aerated and warm the microbiology and fauna become more active and will chomp through organic matter like there is no tomorrow. In doing so there is an increase in soil carbon respiration in the form of carbon dioxide and methane along with other gasses. This increase in respiration can actually help increase plant growth by providing carbon dioxide concentrated around the plant leaves. The increase in microbiological activity also increases nutrient cycling and plant available soil nutrients. However if the plants aren’t putting the carbon back into the soil via their roots, exudates, or plant litter when they die – then over the long term the soil community suffers.
When there is a lack of high carbon input that organic mulch provides to soil organisms, competition for that soil carbon increases. And the less soil carbon, the less complex organisms will survive. This is particularly important for fungi that rely on the carbon because they are made up of more carbon than other microbiology. Worse, the fungi that do survive the hostile conditions are often those that are plant predators able to fight for the carbon needed in order to survive because they now lack competition. As a result those predators infect plants and reduce yields or even kill them, and so gardeners and farmers search for solutions to their fungal problems in the form of fungicides. As a result fungi get a bad name. The same happens to nematodes.
However for short season plants like seasonal crops in Kevin’s example, this may not be much of a problem as the plant may be ready for harvest before the predators have overcome a plants defences, and he’s adding organic matter every year.
To conclude, when organic resources are plentiful, everyone’s happy and works in symbiosis, and when they’re not happy it’s war. Not quite extremophile Star Wars, but certainly localised Planet Wars, and eventually those wars include us higher order carbon beings in Human Wars that result from desertification and a lack of resources.
Plastic mulch is also plastic. Did you know that most sea salt already has microplastics in it after a little over 100 years of plastics use?
This study says that leaf litter was preferred by fungi and root litter by other microbes like bacteria and nematodes, and that herbivorous nematodes were controlled more by leaf litter than root litter.
Probably by the fungi catching the nematodes with lasso! Yeehaw.
It also suggests that cutting plants at the stems and just leaving the roots to feed soil microorganisms may increase nematodes over time, especially when nitrogen or phosphorus is added. Phosphorus is known to negatively impact on fungi populations, while nitrogen amendment can result in plants exuding less carbon from their roots that fungi and other soil microbes feed on, microbes that then fix nitrogen and make other nutrients bioavailable for the plant.
So, if you’re doing a no dig approach to gardening and leaving roots in place, mulch is a must. Whether that’s a carbon source in the form of leaves or a low phosphorus compost mulch or otherwise, basically think of the fungi!
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.
Storage of carbon in the stationary phase.
Signature metabolisms that change with growth phase.
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
The mechanisms driving gut bacterial imbalance.
During episodes of intestinal inflammation – which can occur during IBD and gastrointestinal infections and cancers – the composition of these gut microbial communities is radically disturbed.
“Beneficial bacteria begin to dwindle in numbers as less beneficial, or even harmful, bacteria flourish,” said Ms. Hughes. “This imbalance of microbiota is believed to exacerbate the inflammation.”
A healthy gut is devoid of oxygen. The beneficial bacteria that live there are well-adapted to the low-oxygen environment and break down fiber through fermentation. Unlike these beneficial bacteria, potentially harmful E. coli grow better in high-oxygen environments.
“Inflammation changes the environment so that it is no longer perfect for the commensal anaerobes, but perfect for opportunistic E. coli, which basically wait for an ‘accident’ like inflammation to happen,” Dr. Winter explained.
The increased availability of oxygen during inflammation helps E. coli thrive in an inflamed gut through a metabolic “trick,” Ms. Hughes said.
“Through respiration, the abundant waste products generated by the beneficial microbes can be ‘recycled’ by commensal E. coli – which do not grow well on fiber – and turned into valuable nutrients, thus fueling a potentially harmful bloom of the E. coli population,” she explained.
“If we interfere with the production of waste products by the beneficial commensal bacteria, then we impede their metabolism, which causes them to grow more slowly and throw off the entire ecosystem,” Dr. Winter said. “The most effective strategy may be to inhibit commensal E. coli‘s unique metabolism to avoid the bloom and negative impacts.”
There’s no such thing as ideal. Or is there?
While calculating the ratios of soil elements I made an interesting observation about carbon. Both plant and soil.
We know from previous studies that about 8% soil organic carbon (SOC) is optimum for yield. It turns out that’s about the same amount of carbon in most plants. Coincidence? I think not.
Optimum soil carbon for yield likely correlates with actual plant carbon.
If I take that and assume an 8% SOC 10cm topsoil and a linear decline over 60cm depth, I get 15.75% Total SOC. You see these levels in some forests and Terra Preta.
I wonder what percentage of fungi and bacteria is carbon?… Just checked… and it turns out fungi are about 8%!
Spirulina, a cyanobacteria? 3.12%. If you divide 8% by 3.12% you get a Fungal to Bacteria ratio of 2.56:1.
Meaning you’d need 2.56 fungi to 1 bacteria to get the equivalent of 8% carbon.
What did David Johnson say was ideal Fungi:Bacteria ratio? Well, will you look at that, 2.56 is pretty darn close to the productivity maxima.
So, depending on what you are growing, it could well dictate the ideal soil organic carbon and the bacteria:fungi ratio.
FWIW, if you’re growing a human, then we’re 18.5% carbon… and a vegetarian would need to consume something like 2.3x the amount of food as a carnivore. This is below the bifurcation growth rate of chaos theory at 3.0.