̽��ֱ�� of Cambridge - algae

Shimmering seaweeds and algae antennae: sustainable energy solutions under the sea

sc604 — Thu, 22 Feb 2024 16:40:43 +0000

Funded by the European Union’s Horizon 2020 research and innovation programme, the Bio-inspired and Bionic materials for Enhanced Photosynthesis (BEEP) project, led by Professor Silvia Vignolini in the Yusuf Hamied Department of Chemistry, studied how marine organisms interact with light.

̽��ֱ��four-year sustainable energy project brought together nine research groups from across Europe and drew its inspiration from nature, in particular from the marine world, where organisms including algae, corals and sea slugs have evolved efficient ways to convert sunlight into energy. Harnessing these properties could aid in the development of new artificial and bionic photosynthetic systems.

Some of the brightest and most colourful materials in nature – such as peacock feathers, butterfly wings and opals – get their colour not from pigments or dyes, but from their internal structure alone. ̽��ֱ��colours our eyes perceive originate from the interaction between light and nanostructures at the surface of the material, which reflect certain wavelengths of light.

As part of the BEEP project, the team studied structural colour in marine species. Some marine algae species have nanostructures in their cell walls that can transmit certain wavelengths of visible light or change their structures to guide the light inside the cell. Little is known about the function of these structures, however: scientists believe they might protect the organisms from UV light or optimise light harvesting capabilities.

̽��ֱ��team studied the optical properties and light harvesting efficiency of a range of corals, sea-slugs, microalgae and seaweeds. By understanding the photonic and structural properties of these species, the scientists hope to design new materials for bio-photoreactors and bionic systems.

“We’re fascinated by the optical effects performed by these organisms,” said Maria Murace, a BEEP PhD candidate at Cambridge, who studies structural colour in seaweeds and marine bacteria. “We want to understand what the materials and the structures at the base of these colours are, which could lead to the development of green and sustainable alternatives to the conventional paints and toxic dyes we use today.”

BEEP also studied diatoms: tiny photosynthetic algae that live in almost every aquatic system on Earth and produce as much as half of the oxygen we breathe. ̽��ֱ��silica shells of these tiny algae form into stunning structures, but they also possess remarkable light-harvesting properties.

̽��ֱ��BEEP team engineered tiny light-harvesting antennae and attached them to diatom shells. “These antennae allowed us to gather the light that would otherwise not be harvested by the organism, which is converted and used for photosynthesis,” said Cesar Vicente Garcia, one of the BEEP PhD students, from the ̽��ֱ�� of Bari in Italy. “ ̽��ֱ��result is promising: diatoms grow more! This research could inspire the design of powerful bio-photoreactors, or even better

̽��ֱ��scientists engineered a prototype bio-photoreactor, consisting of a fully bio-compatible hydrogel which sustains the growth of microalgae and structural coloured bacteria. ̽��ֱ��interaction of these organisms is mutually beneficial, enhancing microalgal growth and increasing the volume of biomass produced, which could have applications in the biofuel production industry.

Alongside research, the network has organised several training and outreach activities, including talks and exhibitions for the public at science festivals in Italy, France and the UK.

“Society relies on science to drive growth and progress,” said Floriana Misceo, the BEEP network manager who coordinated outreach efforts. “It’s so important for scientists to share their research and help support informed discussion and debate because without it, misinformation can thrive, which is why training and outreach was an important part of this project.”

“Coordinating this project has been a great experience. I learned immensely from the other groups in BEEP and the young researchers,” said Vignolini. “ ̽��ֱ��opportunity to host researchers from different disciplines in the lab was instrumental in developing new skills and approaching problems from a different perspective.”

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under a Marie Skłodowska-Curie grant.

How could tiny antennae attached to tiny algae speed up the transition away from fossil fuels? This is one of the questions being studied by Cambridge researchers as they search for new ways to decarbonise our energy supply, and improve the sustainability of harmful materials such as paints and dyes.

BEEP

Seaweeds showing structural colour

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Yes

Harnessing the power of algae: new, greener fuel cells move step closer to reality

cjb250 — Wed, 10 Jan 2018 11:18:27 +0000

As the global population increases, so too does energy demand. ̽��ֱ��threat of climate change means that there is an urgent need to find cleaner, renewable alternatives to fossil fuels that do not contribute extensive amounts of greenhouse gases with potentially devastating consequences on our ecosystem. Solar power is considered to be a particularly attractive source as on average the Earth receives around 10,000 times more energy from the sun in a given time than is required by human consumption.

In recent years, in addition to synthetic photovoltaic devices, biophotovoltaics (BPVs, also known as biological solar-cells) have emerged as an environmentally-friendly and low-cost approach to harvesting solar energy and converting it into electrical current. These solar cells utilise the photosynthetic properties of microorganisms such as algae to convert light into electric current that can be used to provide electricity.

During photosynthesis, algae produce electrons, some of which are exported outside the cell where they can provide electric current to power devices. To date, all the BPVs demonstrated have located charging (light harvesting and electron generation) and power delivery (transfer to the electrical circuit) in a single compartment; the electrons generate current as soon as they have been secreted.

In a new technique described in the journal Nature Energy, researchers from the departments of Biochemistry, Chemistry and Physics have collaborated to develop a two-chamber BPV system where the two core processes involved in the operation of a solar cell – generation of electrons and their conversion to power – are separated.

“Charging and power delivery often have conflicting requirements,” explains Kadi Liis Saar, of the Department of Chemistry. “For example, the charging unit needs to be exposed to sunlight to allow efficient charging, whereas the power delivery part does not require exposure to light but should be effective at converting the electrons to current with minimal losses.”

Building a two-chamber system allowed the researchers to design the two units independently and through this optimise the performance of the processes simultaneously.

“Separating out charging and power delivery meant we were able to enhance the performance of the power delivery unit through miniaturisation,” explains Professor Tuomas Knowles from the Department of Chemistry and the Cavendish Laboratory. “At miniature scales, fluids behave very differently, enabling us to design cells that are more efficient, with lower internal resistance and decreased electrical losses.”

̽��ֱ��team used algae that had been genetically modified to carry mutations that enable the cells to minimise the amount of electric charge dissipated non-productively during photosynthesis. Together with the new design, this enabled the researchers to build a biophotovoltaic cell with a power density of 0.5 W/m2, five times that of their previous design. While this is still only around a tenth of the power density provided by conventional solar fuel cells, these new BPVs have several attractive features, they say.

"While conventional silicon-based solar cells are more efficient than algae-powered cells in the fraction of the sun’s energy they turn to electrical energy, there are attractive possibilities with other types of materials," says Professor Christopher Howe from the Department of Biochemistry. “In particular, because algae grow and divide naturally, systems based on them may require less energy investment and can be produced in a decentralised fashion."

Separating the energy generation and storage components has other advantages, too, say the researchers. ̽��ֱ��charge can be stored, rather than having to be used immediately – meaning that the charge could be generated during daylight and then used at night-time.

While algae-powered fuel cells are unlikely to generate enough electricity to power a grid system, they may be particularly useful in areas such as rural Africa, where sunlight is in abundance but there is no existing electric grid system. In addition, whereas semiconductor-based synthetic photovoltaics are usually produced in dedicated facilities away from where they are used, the production of BPVs could be carried out directly by the local community, say the researchers.

“This a big step forward in the search for alternative, greener fuels,” says Dr Paolo Bombelli, from the Department of Biochemistry. “We believe these developments will bring algal-based systems closer to practical implementation.”

̽��ֱ��research was supported by the Leverhulme Trust, the Engineering and Physical Sciences Research Council and the European Research Council.

Reference
Saar, KL et al. Enhancing power density of biophotovoltaics by decoupling storage and power delivery. Nature Energy; 9 Jan 2018; DOI: 10.1038/s41560-017-0073-0

A new design of algae-powered fuel cells that is five times more efficient than existing plant and algal models, as well as being potentially more cost-effective to produce and practical to use, has been developed by researchers at the ̽��ֱ�� of Cambridge.

This a big step forward in the search for alternative, greener fuels

Paolo Bombelli

Kadi Liis Saar

Artist' impression

Researcher Profile: Dr Paolo Bombelli

Dr Paolo Bombelli is a post-doctoral researcher in the Department of Biochemistry, where his research looks to utilise the photosynthetic and metabolic activity of plants, algae and bacteria to create biophotovoltaic devices, a sustainable source of renewable current. He describes himself as “a plants, algae and bacteria electrician”.

“Photosynthesis generates a flow of electrons that keeps plants, algae and other photosynthetic organisms alive,” he explains. “These electrons flow though biological wires and, like the electrical current obtained from a battery and used to power a radio, they are the driving force for any cellular activity.”

Dr Bombelli’s fascination with this area of research began during his undergraduate studies at the ̽��ֱ�� of Milan.

“Plants, algae and photosynthetic bacteria are the oldest, most common and effective solar panels on our planet,” he says. “For billions of years they have been harnessing the energy of the sun and using it to provide oxygen, food and materials to support life. With my work I aim to provide new ways to embrace the potential of these fantastic photosynthetic organisms.”

His work is highly cross-disciplinary, with input from the Departments of Biochemistry, Plant Sciences, Chemistry and Physics, and the Institute for Manufacturing, as well as from researchers at Imperial College London, UCL, the ̽��ֱ�� of Brighton, the Institute for Advanced Architecture of Catalonia in Spain and the ̽��ֱ�� of Cape Town, South Africa.

“Universities are great places to work and so they attract many people,” he says. “People choose to come to Cambridge because they know the ideas they generate here will go on to change the world.”

In 2016, Dr Bombelli won a Public Engagement with Research Award by the ̽��ֱ�� of Cambridge for his work engaging audiences at more than 40 public events, including science festivals and design fairs, reaching thousands of people in seven countries. His outreach work included working with Professor Chris Howe to develop a prototype ‘green bus shelter’ where plants, classical solar panels and bio-electrochemical systems operate in synergy in a single structure.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Opinion: Can we save the algae biofuel industry?

Anonymous — Tue, 10 May 2016 11:18:31 +0000

Algal biofuels are in trouble. This alternative fuel source could help reduce overall carbon emissions without taking land from food production, like many crop-based biofuels do. But several major companies including Shell and ExxonMobil are seemingly abandoning their investments in this environmentally friendly fuel. So why has this promising technology failed to deliver, and what could be done to save it?

Algae are photosynthetic organisms related to plants that grow in water and produce energy from carbon dioxide and sunlight. Single-celled microalgae can be used to produce large amounts of fat, which can be converted into biodiesel, the most common form of biofuel. There are many possible ingredients for making biofuels, from corn to used cooking oil. But algae are particularly interesting because they can be grown rapidly and produce large amounts of fuel relative to the resources used to grow them (high productivity).

In the last decade or so, vast amounts of money have been invested in the development of algae for biofuel production. This made sense because, ten years ago, there was a need to find alternatives to fossil fuels due to the high oil price and the increasing recognition that carbon emissions were causing climate change. Algal biofuels were touted as the answer to these twin problems, and huge investment followed.

Unfortunately, things didn’t go quite to plan. Companies making algal biofuels struggled to retain their high productivity at a larger scale and found predators often contaminated their farms. They also found that the economics just didn’t make sense. Building the ponds in which to grow the algae and providing enough light and nutrients for them to grow proved too expensive, and to make matters worse the oil price has plummeted.

Beyond biofuels

But algae don’t just produce biofuels. In fact, algae are like microscopic factories producing all sorts of useful compounds that can be used to make an amazingly diverse range of products.

For example, algae can produce large amounts of omega-3 fatty acids, an important dietary supplement. This means it could be a sustainable, vegetarian source of omega-3, which is otherwise only available from eating fish or unappetising cod liver tablets. More generally, algae are excellent sources of vitamins, minerals and proteins, with species such as Chlorella and Spirulina commonly being consumed for their health benefits.

Another useful product that can be made from algae is bioplastic. Regular plastic is a product of fossil fuels and takes an extremely long time to break down, which makes it very environmentally unfriendly. Bioplastic from algae can be produced with low carbon emissions, or even in a way that absorbs emissions. Their use could help prevent the build up of plastic in the environment.

̽��ֱ��diversity of these products may be the key to finally developing algal biofuels. Many are high-value chemicals, selling for a much higher price than biofuels. So by combining them with biodiesel production, we could subsidise the price of the fuel and offset the high costs of algal cultivation.

This concept, known as a “biorefinery”, is part of a new wave of algae research that aims to overcome the issues of the past decade or so. We already know that oil refineries produce plastics, fibres and lubricants as well as fuels. Now we are hoping to develop algal biorefineries in exactly the same way.

Could health supplements like this be the solution to our biofuel problems? mama_mia/Shutterstock

Producing an algal biorefinery

To make this model cost-effective and sustainable, we would need to use waste sources of heat, carbon dioxide and nutrients to grow the algae. These are widely available from power plants, factories and water treatment plants and so could reduce some of the costs of growing algae. After making algal fuel, you’re left with lots of proteins, carbohydrates and other molecules. These can be converted into the kinds of products mentioned above, or used to produce biogas (another fuel source). This biogas can be sold or used at the biorefinery to produce heat for the algae, closing the loop and making the whole process more efficient.

It’s easy to see how this process could be a way forward for sustainable, profitable biofuel from algae. In fact, there are companies already applying this concept to their work. In 2014 Sapphire Energy, one of the world’s largest algal biotechnology companies, announced that they were diversifying their work to include nutritional supplements as well as biofuels. This move towards biorefinery is becoming more common and many firms diversifying their product lines.

Clearly, the algal biorefinery will not solve all the problems facing commercial algal cultivation today. There are still key issues facing the loss of yield at very large scales, and the contamination of algal cultures by predators that eat your crop of algae. These issues will only be solved by continued research efforts. However, biorefinery may well be the next step towards a future free from fossil fuels.

Christian Ridley, Research Associate in Plant Biotechnology, ̽��ֱ�� of Cambridge

This article was originally published on ̽��ֱ��Conversation. Read the original article.

̽��ֱ��opinions expressed in this article are those of the individual author(s) and do not represent the views of the ̽��ֱ�� of Cambridge.

Christian Ridley (Department of Plant Sciences) discusses why algae biofuel has failed to deliver, and what could be done to save this promising technology.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Algae use their ‘tails’ to gallop and trot like quadrupeds

sc604 — Tue, 03 May 2016 14:12:54 +0000

Long before there were fish swimming in the oceans, tiny microorganisms were using long slender appendages called cilia and flagella to navigate their watery habitats. Now, new research reveals that species of single-celled algae coordinate their flagella to achieve a remarkable diversity of swimming gaits.

When it comes to four-legged animals such as cats, horses and deer, or even humans, the concept of a gait is familiar, but what about unicellular green algae with multiple limb-like flagella? ̽��ֱ��latest discovery, published in the journal Proceedings of the National Academy of Sciences, shows that despite their simplicity, microalgae can coordinate their flagella into leaping, trotting or galloping gaits just as well.

Many gaits are periodic: whether it is the stylish walk of a cat, the graceful gallop of a horse, or the playful leap of a springbok, the key is the order or sequence in which these limbs are activated. When springboks arch their backs and leap, or ‘pronk’, they do so by lifting all four legs simultaneously high into the air, yet when horses trot it is the diagonally opposite legs that move together in time.

In vertebrates, gaits are controlled by central pattern generators, which can be thought of as networks of neural oscillators that coordinate output. Depending on the interaction between these oscillators, specific rhythms are produced, which, mathematically speaking, exhibit certain spatiotemporal symmetries. In other words, the gait doesn’t change when one leg is swapped with another – perhaps at a different point in time, say a quarter-cycle or half-cycle later.

It turns out the same symmetries also characterise the swimming gaits of microalgae, which are far too simple to have neurons. For instance, microalgae with four flagella in various possible configurations can trot, pronk or gallop, depending on the species.

“When I peered through the microscope and saw that the alga was performing two sets of perfectly synchronous breaststrokes, one directly after the other, I was amazed,” said the paper’s first author Dr Kirsty Wan of the Department of Applied Mathematics and Theoretical Physics (DAMTP) at the ̽��ֱ�� of Cambridge. “I realised immediately that this behaviour could only be due to something inside the cell rather than passive hydrodynamics. Then of course to prove this I had to expand my species collection.”

̽��ֱ��researchers determined that it is in fact the networks of elastic fibres which connect the flagella deep within the cell that coordinate these diverse gaits. In the simplest case of Chlamydomonas, which swims a breaststroke with two flagella, absence of a particular fibre between the flagella leads to uncoordinated beating. Furthermore, deliberately preventing the beating of one flagellum in an alga with four flagella has zero effect on the sequence of beating in the remainder.

However, this does not mean that hydrodynamics play no role. In recent work from the same group, it was shown that nearby flagella can be synchronised solely by their mutual interaction through the fluid. There is a distinction between unicellular organisms for which good coordination of a few flagella is essential, and multicellular species or tissues that possess a range of cilia and flagella. In the latter case, hydrodynamic interactions are much more important.

“As physicists our instinct is to seek out generalisations and universal principles, but the world of biology often presents us with many fascinating counterexamples,” said Professor Ray Goldstein, Schlumberger Professor of Complex Physical Systems at DAMTP, and senior author of the paper. “Until now there have been many competing theories regarding flagellar synchronisation, but I think we are finally making sense of how these different organisms make best use of what they have.”

̽��ֱ��findings also raise intriguing questions about the evolution of the control of peripheral appendages, which must have arisen in the first instance in these primitive microorganisms.

This research was supported by a Neville Research Fellowship from Magdalene College, and a Senior Investigator Award from the Wellcome Trust.

Reference:
Kirsty Y. Wan and Raymond E. Goldstein. ‘Coordinated beating of algal flagella is mediated by basal coupling.’ PNAS (2016). DOI: 10.1073/pnas.1518527113

Species of single-celled algae use whip-like appendages called flagella to coordinate their movements and achieve a remarkable diversity of swimming gaits.

As physicists our instinct is to seek out generalisations and universal principles, but the world of biology often presents us with many fascinating counterexamples.

Raymond Goldstein

Kirsty Y. Wan & Raymond E. Goldstein

Microscope images showing two species of algae which swim using tiny appendages known as flagella

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Bioenergy research blooms in Cambridge

bjb42 — Sun, 01 Aug 2010 14:41:57 +0000

Plants are the most important natural resource on the planet. Not only do they provide all the food we eat, either directly or indirectly as animal feed, but they are also an important source of building materials and biopolymers, such as rubber, as well as many important pharmaceutical products.

Now plants are increasingly being exploited as a source of renewable energy. Plants harness solar radiation by photosynthesis; because this fixes atmospheric CO₂ to produce biomass, using plants as a source of energy is potentially carbon neutral. In addition, compared with other sources of renewable energy, biofuels also offer the major advantage of providing a source of liquid fuel, which is required for transport.

But biofuels have also come under criticism. So-called first-generation biofuels are produced by fermentation of starch from crops such as maize to yield ethanol, or are derived from plant oils yielding biodiesel. Although the amounts produced are small (approximately 3% of European transport fuel energy consumption comes from first-generation biofuels), the use of food crops as a source of raw materials at a time when populations are increasing in size has led to a ‘food versus fuel’ debate.

Sources of alternative biofuel feedstock that don’t compete with food production are needed. Within the past two years, scientists from several Cambridge departments have come together to form the Bioenergy Initiative to explore the potential of next-generation biofuels. These interdisciplinary collaborations are tackling the technical and environmental obstacles that must be addressed to make next-generation biofuels commercially viable. ̽��ֱ��research is focusing on two main areas: developing fuels based on non-food crops and the parts of food crops that are normally discarded as waste, and developing ways of harvesting energy from algae.

Plants for bioenergy

Plant material such as wood and straw has the potential to be part of the low carbon solution to replace our fossil-fuel-based liquid transport fuels, provided an environmentally, socially and economically sustainable production method is found. Plants store most of the carbon they take from the atmosphere in their cell walls as polysaccharides. Instead of burning plants to release energy, the plant biomass could be more usefully converted to liquid fuels such as ethanol by chemically releasing these sugars, and then using microbes to ferment them to fuels. This requires that as much as possible of the cell wall polysaccharides are used, with minimal expenditure of energy and minimal use of expensive chemical and enzymatic treatment to extract them. Much research is needed to make this an industrial reality.

Early in 2009, the UK Biotechnology and Biological Sciences Research Council (BBSRC) announced a £27 million investment in research in this area. ̽��ֱ��new virtual BBSRC Sustainable Bioenergy Centre (BSBEC) is a partnership of six research hubs and industry. As part of this, Dr Paul Dupree in the Department of Biochemistry leads the BSBEC Cell Wall Sugars Programme in Cambridge. ̽��ֱ��Programme aims to improve the energy conversion process by understanding how sugars are locked into the plant biomass.

Up to 10 million tonnes of wheat straw could be available in the UK each year for energy production. If converted to ethanol, this could generate a few percent of UK transport fuel requirements. Increases beyond this are possible if crops such as willow or Miscanthus grass are grown on land that is unsuitable for food crops. Cambridge BSBEC researchers are contributing to studies on the farming of these crops at Rothamsted Research, Hertfordshire, to improve yields and to understand how to optimise sustainability of the crops in terms of energy input and biodiversity.

By analysing how sugars are locked into plant cell walls, research in the Dupree group aims to identify the best plants and the right enzymes to release the maximum amount of sugars for conversion to biofuels. ̽��ֱ��research team is building links with industry and other research centres to ensure their findings will increase the sustainable use of plants for fuels and other renewable products.

Pond slime to the rescue

̽��ֱ��other major strand of research being undertaken in the Initiative has focused on algae. These simple aquatic plants are responsible for an estimated 50% of global carbon fixation and offer considerable advantages compared with biofuels from land crops. Many species are able to produce high levels of hydrocarbons, and they can also divert photosynthetic energy into another ready-to-use fuel, hydrogen. Algal productivity can be much higher than that of land plants per unit area, because of their fast growth rates, and they can be grown on marginal land, or even offshore, where they don’t compete with food crops.

However, there is little or no infrastructure for the cultivation and harvesting of microalgae on a large scale, apart from commercial operations employed for the production of high-value products such as the food supplement astaxanthin, which is used in the fish industry. Moreover, for fuel production, cost margins are critical, and most importantly the energy that is obtained from the fuel extracted must be greater than that used in the process. To address some of the many difficulties that will be encountered in attempts to commercialise biofuel production from algae, the Algal Bioenergy Consortium (ABC) was founded in 2007 by Professor Alison Smith (Department of Plant Sciences), together with Professor Chris Howe (Biochemistry), Dr John Dennis (Chemical Engineering and Biotechnology) and Dr Stuart Scott (Engineering).

A major issue is which algal species to grow. Although most people are familiar with the two broad categories of algae – seaweed on the beach or the scum that grows on ponds or on the patio – the algal kingdom is incredibly diverse. However, our knowledge of algal biology in general is poor, and we know even less about how these organisms would behave in the large-scale dense cultures that would be needed for biofuel feedstock production.

̽��ֱ��research focus of the ABC is to study a few species in depth, taking advantage of molecular tools that are being developed for some model species. Through studying ways in which algae make fuel molecules and how the algal cell wall is built, the researchers aim to discover ways to increase the extraction of fuel molecules with maximum yields.

Together with Dr Adrian Fisher in the Department of Chemical Engineering and Biotechnology, the ABC is also investigating ways of harvesting hydrogen as an energy source in a biophotovoltaic device. ̽��ֱ��method is based on ‘stealing’ electrons from the photosynthetic process. Although currents so far are low, with funding from the Engineering and Physical Sciences Research Council (EPSRC) and the formation of a ̽��ֱ�� spin-out, H+ Energy, the combination of biological and engineering approaches is helping to optimise the prototypes.

Part of the energy spectrum

At the present time, an estimated 1 million years’ worth of fossil fuel deposition is consumed each year. As fossil fuels become scarcer and more expensive to extract, and carbon emissions increase as a result of their use, renewable sources of energy will be essential. Given the size of the challenge to provide energy security in a sustainable way, it is important to explore the entire spectrum of possible energy sources. Biofuels from plants and algae have the potential to offer both a sustainable and carbon-neutral supply, but many hurdles need to be overcome before this potential is realised. With the critical mass of bioenergy researchers now working in Cambridge, the Bioenergy Initiative has the opportunity to play a major role in tackling these issues.

For more information, please contact the authors Professor Alison Smith (as25@cam.ac.uk) at the Department of Plant Sciences and Dr Paul Dupree (pd101@cam.ac.uk) at the Department of Biochemistry, or visit www.bioenergy.cam.ac.uk/

̽��ֱ��Bioenergy Initiative is bringing biology and engineering together to address the challenge of meeting our future energy needs.

Alison Smith

Algae

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Yes

Scientists discover ‘dancing’ algae

bjb42 — Tue, 21 Apr 2009 00:00:00 +0000

̽��ֱ��researchers studied the multicellular organism Volvox, which consists of approximately 1,000 cells arranged on the surface of a spherical matrix about half a millimetre in diameter. Each of the surface cells has two hair-like appendages known as flagella, whose beating propels the colony through the fluid and simultaneously makes them spin about an axis.

̽��ֱ��researchers found that colonies swimming near a surface can form two types of "bound states"; the "waltz", in which the two colonies orbit around each other like a planet circling the sun, and the "minuet", in which the colonies oscillate back and forth as if held by an elastic band between them.

̽��ֱ��researchers have developed a mathematical analysis that shows these dancing patterns arise from the manner in which nearby surfaces modify the fluid flow near the colonies and induce an attraction between them. ̽��ֱ��observations constitute the first direct visualisations of the flows, which have been predicted to produce such an attraction. They have been implicated previously in the accumulation of swimming microorganisms such as bacteria and sperm cells near surfaces.

These findings also have implications for clustering of colonies at the air-water interface, where these recirculating flows can enhance the probability of fertilization during the sexual phase of their life cycle.

Professor Raymond E. Goldstein, the Schlumberger Professor of Complex Physical Systems in the Department of Applied Mathematics and Theoretical Physics (DAMTP) and lead author of the study, said: "These striking and unexpected results remind us not only of the grace and beauty of life, but also that remarkable phenomena can emerge from very simple ingredients."

Funded by the Biotechnology and Biological Sciences Research Council (BBSRC), the work is part of a larger effort to improve our knowledge of evolutionary transitions from single-cell organisms to multicellular ones. This greater understanding of the nature of self-propulsion and collective behaviour of these organisms promises to elucidate key evolutionary steps toward greater biological complexity.

Moreover, the flagella of Volvox are nearly identical to the cilia in the human body, whose coordinated action is central to many processes in embryonic development, reproduction, and the respiratory system. For this reason, the study of flagellar organisation has potentially broad implications for human health and disease.

̽��ֱ��group was led by Professor Goldstein and included Ph.D. student Knut Drescher, postdoctoral researchers Drs. Idan Tuval and Kyriacos C. Leptos, Professor Timothy J. Pedley of DAMTP, and Prof. Takuji Ishikawa of Tohoku ̽��ֱ��, Japan.

Scientists at Cambridge ̽��ֱ�� have discovered that freshwater algae can form stable groupings in which they dance around each other, miraculously held together only by the fluid flows they create. Their research was published today in the journal Physical Review Letters

These striking and unexpected results remind us not only of the grace and beauty of life, but also that remarkable phenomena can emerge from very simple ingredients.

Professor Raymond E. Goldstein

kewl from Flickr

Green Algae

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Yes