The spread of a disease that is decimating global bee populations is manmade, and driven by European honeybee populations, new research has concluded.
A study led by the University of Exeter and UC Berkeley and published in the journal Science found that the European honeybee Apis mellifera is overwhelmingly the source of cases of the Deformed Wing Virus infecting hives worldwide. The finding suggests that the pandemic is manmade rather than naturally occurring, with human trade and transportation of bees for crop pollination driving the spread.
Although separately they are not major threats to bee populations, when the Varroa mite carries the disease, the combination is deadly, and has wiped out millions of honeybees over recent decades. Varroa feed on bee larvae while the Deformed Wing Virus kills off bees, a devastating double blow to colonies. The situation is adding to fears over the future of global bee populations, with major implications for biodiversity, agricultural biosecurity, global economies, and human health.
The study was funded by the Natural Environment Research Council (NERC) and supported by a Royal Society Dorothy Hodgkin Fellowship. It involved collaborators from the universities of Sheffield, Cambridge, Salford and UC Berkeley, as well as ETH Zurich in Switzerland.
Lead author Dr Lena Wilfert, of the University of Exeter’s Centre for Ecology and Conservation, on the Penryn Campus in Cornwall, said: “This is the first study to conclude that Europe is the backbone of the global spread of the bee killing combination of Deformed Wing Virus and Varroa. This demonstrates that the spread of this combination is largely manmade – if the spread was naturally occurring, we would expect to see transmission between countries that are close to each other, but we found that, for example, the New Zealand virus population originated in Europe. This significantly strengthens the theory that human transportation of bees is responsible for the spread of this devastating disease. We must now maintain strict limits on the movement of bees, whether they are known to carry Varroa or not. It’s also really important that beekeepers at all levels take steps to control Varroa in their hives, as this viral disease can also affect wild pollinators.”
Researchers analysed sequence data of Deformed Wing Virus samples across the globe from honeybees and Varroa mites, as well as the occurrence of Varroa. They used the information to reconstruct the spread of Deformed Wing Virus and found that the epidemic largely spread from Europe to North America, Australia and New Zealand. They found some two-way movement between Europe and Asia, but none between Asia and Australasia, despite their closer proximity. The team also looked at samples from other species suspected of transmitting the disease, including different species of honeybee, mite and bumblebees, but concluded that the European honeybee was the key transmitter.
Professor Roger Butlin, Professor of Evolutionary Biology at the University of Sheffield, said: “Our study has found that the deformed wing virus is a major threat to honeybee populations across the world and this epidemic has been driven by the trade and movement of honeybee colonies.
“Domesticated honeybee colonies are hugely important for our agriculture systems, but this study shows the risks of moving animals and plants around the world. The consequences can be devastating, both for domestic animals and for wildlife. The risk of introducing viruses or other pathogens is just one of many potential dangers.”
Senior author Professor Mike Boots of Exeter and UC Berkeley concluded: “The key insight of our work is that the global virus pandemic in honeybees is manmade not natural. It’s therefore within our hands to mitigate this and future disease problems.”
By combining semiconducting nanowires and bacteria, researchers can now produce liquid fuel.
Three pioneers in the field of synthetic photosynthesis discuss the potential of this technology and the challenges that must be overcome to make it commonplace.
Imagine creating artificial plants that make gasoline and natural gas using only sunlight. And imagine using those fuels to heat our homes or run our cars without adding any greenhouse gases to the atmosphere. By combining nanoscience and biology, researchers led by scientists at University of California, Berkeley, have taken a big step in that direction.
Peidong Yang, a professor of chemistry at Berkeley and co-director of the school’s Kavli Energy NanoSciences Institute, leads a team that has created an artificial leaf that produces methane, the primary component of natural gas, using a combination of semiconducting nanowires and bacteria. The research, detailed in the online edition of Proceedings of the National Academy of Sciences in August, builds on a similar hybrid system, also recently devised by Yang and his colleagues, that yielded butanol, a component in gasoline, and a variety of biochemical building blocks.
The research is a major advance toward synthetic photosynthesis, a type of solar power based on the ability of plants to transform sunlight, carbon dioxide and water into sugars. Instead of sugars, however, synthetic photosynthesis seeks to produce liquid fuels that can be stored for months or years and distributed through existing energy infrastructure.
It could be the key to large-scale implementation of carbon capture
Carbon capture is a process by which waste carbon dioxide (CO2) released by factories and power plants is collected and stored away, in order to reduce global carbon emissions. There are two major ways of carbon capture today, one using powder-like solid materials which “stick” to CO2, and one using liquids that absorb it. Despite their potential environmental and energy benefits, current carbon capture strategies are prohibitive because of engineering demands, cost and overall energy-efficiency. Collaborating scientists from EPFL, UC Berkley and Beijing have combined carbon-capturing solids and liquids to develop a “slurry” that offers the best of both worlds: as a liquid it is relatively simple to implement on a large scale, while it maintains the lower costs and energy efficiency of a solid carbon-capturing material. The breakthrough method is published in Nature Communications.
The most common approach to carbon capture uses liquid amine solutions, which can absorb CO2 from the atmosphere. On a large scale, the system uses two columns, one for capturing CO2 and the other for releasing it from the liquid, in a process referred to as “regeneration”. For amine solutions, regeneration is the most energy-consuming part because the CO2 is so strongly bound to the amine molecules that it is necessary to actually boil them in order to separate them.
An alternative to liquids is to use solid materials known as “metal-organic frameworks” (MOFs). These are fine powders whose particles are made up of metal atoms that are connected into a 3D structure with organic linkers. Their surface is covered with nano-size pores that collect CO2 molecules. But despite its lower cost, as this method involves transporting solids it is very demanding in terms of engineering. Berend Smit, Director of the Energy Center at EPFL, explains: “Imagine trying to walk with a plateful of baby powder. It’s going to go everywhere, and it’s very difficult to control.”
Working with scientists from Beijing and UC Berkeley, Smit is a lead author on a breakthrough carbon-capture innovation that uses a mixture of solid and liquid in solution called a “slurry”. The solid part of the slurry is a MOF called ZIF-8, which is suspended in a 2-methylimidazole glycol liquid mixture.
“Why a slurry?” says Smit. “Because in the materials that are currently used for adsorption the pores are too large and the surrounding liquid would fill them, and not let them capture CO2 molecules. So here we looked at a material – ZIF-8 – whose pores are too small for the glycol’s molecules to fit, but big enough for capturing the CO2 molecules from flue gas.”
ZIF-8 is a good material for carbon-capturing slurries, because it displays excellent solution, chemical and thermal stability, which is important for repeated regeneration cycles. ZIF-8 crystals have narrow pores (3.4 Å in diameter) that are smaller than the diameter of glycol molecules (4.5 Å), preventing them from entering. Even though other liquids were tested in the design of the slurry, including ethanol, hexane, methylbenzene and tetrachloromethane, their molecules are small enough to enter the ZIF-8 pores and reduce its carbon capturing efficiency. In this respect, glycerol has so far been shown to be an ideal liquid.