Friday, April 8, 2016

Report Shows How to Say Goodbye to Harmful Algal Blooms

Date: April 7, 2016

Source: Ohio State University

Summary: Harmful algal blooms dangerous to human health and the Lake Erie ecosystem--such as the one that shut down Toledo's water supply for two days in 2014--could become a problem of the past. Scientists have reported on approaches to reduce harmful algal blooms on Lake Erie.



Jay Martin, an ecological engineer with The Ohio State University, poses next to the Maumee River in Toledo, Ohio, in this 2015 photo.
Credit: Photo: Ken Chamberlain, CFAES.

Harmful algal blooms dangerous to human health and the Lake Erie ecosystem--such as the one that shut down Toledo's water supply for two days in 2014--could become a problem of the past.

A new report shows that if farmers apply agricultural best management practices (BMPs) on half the cropland in the Maumee River watershed, the amount of total phosphorus and dissolved reactive phosphorus leaving the watershed would drop by 40 percent in an average rainfall year -- the amount agreed to in the 2012 Great Lakes Water Quality Agreement between the U.S. and Canada.

Scientists believe that a drop of this magnitude would keep algal blooms at safe levels for people and the lake.

"With aggressive adoption of best management practices, it is possible to reduce harmful algal blooms to safe levels while maintaining agricultural productivity," said Jay Martin, ecological engineer in The Ohio State University's College of Food, Agricultural, and Environmental Sciences and co-author of the study.

The study, "Informing Lake Erie Agriculture Nutrient Management Via Scenario Evaluation," was a collaborative effort between the University of Michigan as the lead, The Nature Conservancy, Heidelberg University, LimnoTech, Texas A&M and Ohio State.

It reviewed 12 approaches to reducing total and dissolved reactive phosphorus and concluded that two of them would result in a 40 percent reduction on average.

"All 12 of the modeled scenarios produced results beneficial to phosphorus reduction," said Don Scavia, lead author of the study, environmental engineer and director of the University of Michigan's Graham Sustainability Institute.

Of the scenarios that reached the 40 percent threshold, one was an extreme approach unlikely to be implemented, Scavia said. That extreme approach showed that 1.5 million crop acres would need to be converted into grassland to meet the targets, if no additional BMPs were employed on agricultural lands.

On the other hand, "the most promising scenarios included widespread use of in-field and edge-of-field nutrient management practices, especially subsurface application of phosphorus fertilizers, expansion of cover crops and creation of buffer strips," he said.

The BMPs are practices farmers have successfully used for decades, said Martin, who also leads Ohio State's Field to Faucet water quality initiative. They include subsurface fertilizer application, cover crops, fertilizing according to soil tests and installing buffer strips to intercept runoff.

Solutions must be good for both water, farmers

"The BMP scenarios are more sustainable because they can sustain agricultural productivity while improving water quality," Martin said. "To move forward, it is most important to find solutions that both improve water quality and maintain economic returns for farmers."

In the most promising BMP scenario, about 1 percent of the land in the watershed, or about 30,000 acres, would need to be converted to buffer strips, and about half the farm acreage would need to have cover crops and subsurface phosphorus applications. Farmers in the watershed are already implementing some of these BMPs, and so are on the way to reaching the 50 percent adoption level that would be necessary, Scavia said. A scenario that included enhanced nutrient management on all the cropland was also effective in reaching this goal.

While the BMPs are familiar to farmers, "It's clear that broadening their use as much as needed will be a big lift," Martin said. "What will help is the additional $41 million that USDA announced it would invest in the Western Lake Erie Basin. This represents a significant investment that would help reach the 40 percent goal."

The U.S. Department of Agriculture's Natural Resources Conservation Service (NRCS) announced theinvestment March 28 at Maumee Bay State Park near Toledo. The dollars will be used to support farmer implementation of conservation practices.

Funding will help implement best practices

"This, along with other innovative efforts like water trusts, cost shares, drain fee incentives, and public-private partnerships that are already underway within the Lake Erie Basin and other parts of the Great Lakes, provide examples of how to make this happen," Martin said.

"The challenge is how to integrate and scale up these and other parts of the solution to treat the number of acres needed to see measureable improvements in water quality," he said.

The researchers chose the Maumee watershed because it has the most impact on the Western Lake Erie Basin, where most of the dangerous algal blooms occur. Information from the study could likely be applied to other agriculturally dominated watersheds with similar slopes, soil types, crop rotations and drainage, Scavia said, but current BMP use would need to be determined.

"The study's models provided the best available advice on both the scale and direction of change needed to meet the new load targets, and they suggested multiple pathways for it. But, as with all modeling of this sort, they may have under- or overestimated what is needed," Scavia said.

"The real test is to begin implementing the change, tracking implementation progress, measuring environmental outcomes, and adjusting both the models and the actions if needed," he said.

The report can be found online at: http://graham.umich.edu/media/pubs/InformingLakeErieAgricultureNutrientManagementviaScenarioEvaluation.pdf

Story Source: Ohio State University. "Report shows how to say goodbye to harmful algal blooms." ScienceDaily. ScienceDaily, 7 April 2016. .

Tuesday, March 22, 2016

Antibiotic Resistance: It's a Social Thing

Date: March 15, 2016
Source: University of York
Summary: Trace concentrations of antibiotic, such as those found in sewage outfalls, are enough to enable bacteria to keep antibiotic resistance, new research has found. The concentrations are much lower than previously anticipated, and help to explain why antibiotic resistance is so persistent in the environment.


Aerial view of sewage water treatment plant.
Credit: © josefkubes / Fotolia

Trace concentrations of antibiotic, such as those found in sewage outfalls, are enough to enable bacteria to keep antibiotic resistance, new research from the University of York has found. The concentrations are much lower than previously anticipated, and help to explain why antibiotic resistance is so persistent in the environment.

Antibiotic resistance can work in different ways. The research described the different mechanisms of resistance as either selfish or co-operative. A selfish drug resistance only benefits the individual cell with the resistance while a co-operative antibiotic resistance benefits both the resistant cell and surrounding cells whether they are resistant or not.

The researchers analysed a plasmid called RK2 in Escherichia coli, a bacterium which can cause infectious diarrhea. RK2 encodes both co-operative resistance to the antibiotic ampicillin and selfish resistance to another antibiotic, tetracycline. They found that selfish drug resistance is selected for at concentrations of antibiotic around 100-fold lower than would be expected -- equivalent to the residues of antibiotics found in contaminated sewage outfalls.

The study, which is published in Antimicrobial Agents and Chemotherapy (AAC), involved Professor Michael Brockhurst, Dr Jamie Wood and PhD student Michael Bottery in the Departments of Biology and Mathematics at York. The work was supported by the European Research Council under the EU's Seventh Framework Programme and the Wellcome Trust.

Dr Wood said: "The most common way bacteria become resistant to antibiotics is through horizontal gene transfer. Small bits of DNA, called plasmids, contain the resistance and can hop from one bacteria to another. Worse still, plasmids often contain more than one resistance."

Michael Bottery added: "There is a reservoir of antibiotic resistance out there which bacteria can pick and choose from. What we have found is some of that resistance can exist at much lower concentrations of antibiotic than previously understood."

Source: University of York. "Antibiotic resistance: it's a social thing." ScienceDaily. ScienceDaily, 15 March 2016. .

Friday, March 11, 2016

New Report: Attribution of Extreme Weather Events in the Context of Climate Change

A new report from the National Academies of Sciences, Engineering, and Medicine concludes it is now possible to estimate the influence of climate change on some types of extreme events. Confidence is strongest in attributing types of extreme events that are influenced by climate change through a well-understood physical mechanism, such as, the more frequent heat waves that are closely connected to human-caused global temperature increases, the report finds. Confidence is lower for other types of events, such as hurricanes, whose relationship to climate change is more complex and less understood at present. For any extreme event, the results of attribution studies hinge on how questions about the event’s causes are posed, and on the data, modeling approaches, and statistical tools chosen for the analysis. Read a 4-page summary of the report's findings and download the report for free.

Wednesday, January 6, 2016

More Environmentally-Friendly Concrete Made Using Sugar Cane Residue

Date: January 4, 2016
Source: Asociación RUVID
Summary: A new type of concrete has been developed that is cheaper and much less polluting to the environment. Researchers have swapped in sugar cane straw ash, a crop residue typically discarded as waste, as a substitute for Portland cement.

Researchers from the Universitat Politècnica de València (Polytechnic University of Valencia, UPV) and San Paolo State University (Unesp) have developed a new type of concrete that is cheaper and much less polluting to the environment. They have done so by swapping in sugar cane straw ash, a crop residue typically discarded as waste, as a substitute for Portland cement.

Currently pursued at laboratory scale only, the results of this work have been published in the Construction and Building Materials journal. They also form part of Brazilian student João Cláudio Bassan de Moraes's master's dissertation, directed by lecturer Mauro Tashima, who completed his PhD at the UPV and is currently lecturing at Unesp.

Talking to us about the project, Jordi Payá, researcher at the Concrete Science and Technology Institute (ICITECH) at the UPV, explains: "The harvester strips the cane, discarding the tops and leaves as waste. This is the raw material we work with, sugar cane straw." In total around 650 million tonnes of sugar cane are harvested in Brazil every year. Of this, between 15 and 20% corresponds to sugar straw, which is left on the field and either burned or left to decay naturally.

So far, the international research team has been able to obtain concrete using 30% less Portland cement, substituting it with the ashes obtained from burning the sugar cane straw.

"The cement itself is the most expensive and most polluting ingredient of concrete, which makes the benefits [of this new method] as much economic as environmental. We are also making use of a by-product that is currently unexploited, with all the benefits that this entails" (Payá).

Process

To burn the waste, UPV and Unesp researchers have designed a bespoke combustion burner, into which the raw material must be fed following a strict procedure. "Through this process we obtain ashes that are very reactive to the cement, a quality that is very important to the mechanical performance of the resulting concrete, to its resistance to compression, for instance" (Payá).

Work has focused primarily on the microstructural analysis of the concrete. "In the lab we analyse the chemical compounds of the ashes and of the compounds produced during the reaction with the cement, in order to assess their performance in the final product," explains Payá. Future work would include studying indicators related to the durability of mass and reinforced concrete.

The ICITECH research team also studies the use of other agricultural waste as a cement substitute, including the bamboo leaf.


Story Source: The above post is reprinted from materials provided by Asociación RUVID.

Thursday, December 17, 2015

Our Water Pipes Crawl with Millions of Bacteria

Date: December 16, 2015

Source: Lund University

Summary: Our drinking water is to a large extent purified by millions of "good bacteria" found in water pipes and purification plants, Swedish researchers have found. So far, the knowledge about them has been practically non-existent, but this new research is about to change that.


A glass of water contains millions of bacteria, say researchers.
Credit: © Andrey Kuzmin / Fotolia

Researchers from Lund University in Sweden have discovered that our drinking water is to a large extent purified by millions of "good bacteria" found in water pipes and purification plants. So far, the knowledge about them has been practically non-existent, but this new research is about to change that.

A glass of clean drinking water actually contains ten million bacteria! But that is as it should be -- clean tap water always contains harmless bacteria. These bacteria and other microbes grow in the drinking water treatment plant and on the inside of our water pipes, which can be seen in the form of a thin, sticky coating -- a so-called biofilm. All surfaces from the raw water intake to the tap are covered in this biofilm.

Findings by researchers in Applied Microbiology and Water Resources Engineering show that the diversity of species of bacteria in water pipes is huge, and that bacteria may play a larger role than previously thought. Among other things, the researchers suspect that a large part of water purification takes place in the pipes and not only in water purification plants.

"A previously completely unknown ecosystem has revealed itself to us. Formerly, you could hardly see any bacteria at all and now, thanks to techniques such as massive DNA sequencing and flow cytometry, we suddenly see eighty thousand bacteria per millilitre in drinking water," says researcher Catherine Paul enthusiastically.

"From having been in the dark with a flashlight, we are now in a brightly lit room, but it is only one room. How many different rooms are in the house is also an interesting question!" she continues.

The work of doctoral student Katharina Lührig, who works together with Catherine, professors Peter Rådström and Kenneth Persson, and colleagues Björn Canbäck and Tomas Johansson has been published in Microbes and Environments.

The results have led to lively discussions within the industry about the role of biofilms in drinking water.

At least a couple of thousand different species live in the water pipes. According to the researchers there is a connection between the composition of bacteria and water quality.

"We suspect there are 'good' bacteria that help purify the water and keep it safe -- similar to what happens in our bodies. Our intestines are full of bacteria, and most the time when we are healthy, they help us digest our food and fight illness, says Catherine Paul.

Although the research was conducted in southern Sweden, bacteria and biofilms are found all over the world, in plumbing, taps and water pipes. This knowledge will be very useful for countries when updating and improving their water pipe systems.

"The hope is that we eventually may be able to control the composition and quality of water in the water supply to steer the growth of 'good' bacteria that can help purify the water even more efficiently than today," says Catherine Paul.


Story Source:
The above post is reprinted from materials provided by Lund University.

Tuesday, November 17, 2015

Bacteria, Graphene and Nanotech Produce Usable Electricity From Wastewater


Check out the kitchen timer counting down in the gif above. There’s nothing special about it except for how it is being powered. The instrument isn’t equipped with batteries. In fact, its electricity comes from the vial behind it, where bacteria are eating organic matter in wastewater and producing electricity as a result.

It’s the first time that researchers have produced enough electricity for practical use from what are called microbial fuel cells. Scientists in China reported their breakthrough late last week in the journal Science Advances. Their work could one day help provide the huge amounts of power needed to treat wastewater, a process that currently consumes up to 5 percent of all the electricity produced in the U.S.

For a while now, researchers have been investigating the bacterium Shewanella oneidensis, which naturally targets heavy metal ions and other pollutants in wastewater as a source of energy. The bacterium reduces these materials as a way to power its own metabolism, meanwhile converting them into less harmful derivatives. Engineers have figured out how to tap S. oneidensis’s to start harvesting the current for human use, but so far they haven’t been able to get enough out of the reaction because of technological limitations to do anything useful.

Shenlong Zhao and colleagues focused their work not on the bacterium, but on the material part of the battery that collects the electrons the microbe harvests. They worked out a better electrode made of a three-dimensional graphene aerogel decorated with platinum nanoparticles. The aerogel’s complex pores allows the microbe to colonize throughout it, maximizing the density of cells. The platinum nanoparticles, meanwhile, improve the material’s conductivity while also creating an environment more amenable to the organism’s survival.

The power output is enough for two of the vial-sized microbial fuel cells to power the kitchen timer. Meanwhile, tests with the fuel cells running on wastewater retrieved from a Beijing treatment plant indicated that real-world municipal wastewater could be used to produce electricity. Zhao’s team are now setting their sights on scaling up their preliminary work into larger applications.

Top gif: Digital photo of microbial fuel cells driving a timer. The two single biofuel cells have been assembled in series and successfully run a timer, strongly exemplifying that the graphene aerogel/platinum nanoparticle anode enables the superior performance and the actual application potential. Video and caption courtesy of Zhao et al./Science Advances.

Source: http://txchnologist.com/post/133351599065/bacteria-graphene-and-nanotech-produce-usable

Monday, November 9, 2015

Structure of 'Concrete Disease' Solved

Previously undocumented sheet-silicate crystal structure


Date: November 5, 2015
Source: Swiss Federal Laboratories for Materials Science and Technology (EMPA)
Summary: When bridges, dam walls and other structures made of concrete are streaked with dark cracks after a few decades, the culprit is AAR: the alkali-aggregate reaction. AAR damages concrete structures all over the world and makes complex renovations or reconstructions necessary. Researchers have now solved the structure of the material produced in the course of AAR at atomic Level.


Researchers from the Paul Scherrer Institute (PSI) teamed up with colleagues from the Swiss Materials Science Lab Empa to study a degenerative sign of ageing in concrete: the so-called alkali-aggregate reaction (AAR). In the course of AAR, a material forms that takes up more space than the original concrete and thus gradually cracks the concrete from within as the decades go by.

The researchers have now explored the exact structure of this material. They managed to demonstrate that its atoms are arranged extremely regularly, making it a crystal. They also showed that the structure of this crystal is a so-called sheet-silicate structure. This specific structure had never been observed before. The researchers made their discovery thanks to measurements at the Swiss Light Source SLS at PSI. The research results could help towards the development of more durable concrete in future.

A Global Problem

AAR is a chemical reaction that affects outdoor concrete structures all over the world. It happens when concrete is exposed to water or moisture. For instance, numerous bridges and up to twenty per cent of the dam walls in Switzerland are affected by AAR. With AAR, the basic ingredients in the concrete are actually the problem: cement -- the main component of concrete -- contains alkali metals such as sodium and potassium. Any moisture infiltrating the concrete -- stemming for example from rainwater -- reacts with these alkali metals, leading to an alkaline solution.

The second main ingredient in concrete is sand and gravel, which in turn are composed of minerals, such as quartz or feldspar. Chemically speaking, these minerals are so-called silicates. The alkaline water reacts with these silicates and forms a so-called alkali calcium silicate hydrate. This is itself able to absorb more moisture, which causes it to expand and gradually crack the concrete from within. This entire process is referred to as AAR.

AAR takes place extremely slowly, so that the cracks are initially only tiny and invisible to the naked eye. Over the course of three or four decades, however, the cracks widen significantly and eventually jeopardise the durability of the entire concrete structure.

A New Crystal

Even if the chemical processes involved in AAR have long been known, nobody had identified the physical structure of the alkali calcium silicate hydrate formed in the course of AAR. The researchers at PSI and Empa have now managed to fill this knowledge gap. They studied the substance of a Swiss bridge constructed in 1969, which has been affected heavily by AAR. Researchers from Empa cut out a material sample from the bridge and ground down a small piece of it until they were left with a wafer-thin sample that was merely 0.02 millimetres thick. The sample was then taken to the Swiss Light Source SLS and irradiated with an extremely narrow x-ray beam, fifty times thinner than a human hair. Performing so-called diffraction measurements and a complex data analysis, the PSI researchers were eventually able to determine the crystal structure of the material with pinpoint precision.

They found that the alkali calcium silicate hydrate has a previously undocumented sheet-silicate crystal structure. "Normally, discovering an uncatalogued crystal structure means you get to name it," explains Rainer Dähn, the first author of the study. "But it has to be a crystal found in nature, therefore we didn't get that honour," says the researcher with a smile. Andreas Leemann, Head of the Concrete Technology Group at Empa, had the idea for the current study. The researchers from PSI then brought their knowledge of the x-ray beam method to the table. "In principle, it's possible to add organic materials to the concrete that are able to reduce the build-up of tension," explains materials scientist Leemann. "Our new results provide a scientific basis for these considerations and could pave the way for the development of new materials.

Story Source: Swiss Federal Laboratories for Materials Science and Technology (EMPA). "Structure of 'concrete disease' solved: Previously undocumented sheet-silicate crystal structure." ScienceDaily. ScienceDaily, 5 November 2015. .