EU – More Than A Dodo

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

Across an entire desert or ocean, migratory birds make some of the most extreme journeys found in nature, but there are still huge gaps in our understanding of how they manage to travel these vast distances and what a changing climate means for their migration patterns.

‘Some species of migrants might be affected by a changing climate,’ said Professor Stuart Bearhop, an animal ecology expert from the University of Exeter. ‘There is evidence from a number of populations that climate change probably is going to have some impact on the demography (population levels).’

Bearhop ran the STATEMIG project, which studied the migration of Brent Geese along their journey from Ireland to the Arctic where they breed. He found that the volatility of today’s seasons was affecting the geese’s population levels because the weather was playing havoc with their breeding patterns.

‘Wet years are predicted to increase with climate change as temperature rises, but, of course, because they travel so far north, it doesn’t mean rain, it means snow,’ he said. Brent Geese are more likely to breed when the weather is cold and clear, but when there is more snow there are fewer places to safely raise their young and feed.

The team observed that in the colder years the birds were breeding later in the year, causing ripple effects for their populations. The geese did not have enough time to raise their offspring to independence before winter, or there was not enough food for them to survive.

Bearhop says the snowy years saw more offspring die or be abandoned by adults. That means if snowy years persist then it could pose a long-term risk to the population of these birds.

Brent Geese

Bearhop chose Brent Geese because they follow a routine migration and their young stay with their parents for at least a year. These reliable patterns reveal useful insights into population levels and what could be affecting their migration.

To gather their data, STATEMIG researchers observed the geese in Ireland and Iceland before the birds flew to the Arctic to breed around July. In Ireland and Iceland they attached identity tags to the birds and took some physical measurements to use as reference points over several years.

When the geese returned to Ireland and Iceland around late August, with their chicks, the researchers could compare the population levels and get an idea of how environmental factors had shaped their journeys.

‘There are multiple factors that have likely driven the evolution of migration, these likely differ among species and the debate is about which ones are most important,’ said Bearhop.

Debate

Bearhop says the two key reasons birds migrate is because of a competition of territory and to take advantage of seasonal ‘pulses’ of vegetation growth or gluts of insects to ensure they have enough food to raise their young.

STATEMIG’s research emphasises the importance of the latter and Bearhop hopes it could lead to further research that explores how changes to feeding grounds will affect populations of migratory birds.

According to Dr Sissel Sjöberg, a bird migration researcher from the University of Copenhagen, Denmark, scientists understand some parts of why birds migrate, like knowing where they eat and breed, but they do not have the tools to accurately understand them during the entire migration.

For instance, there are high resolution tags that can be put on some big birds to track their location, but these do not fit on smaller birds which make up most of the ones migrating.

Tiny backpacks worn by noctural small birds contain a pressure sensor which provides an update every five minutes of the birds’ behaviour during migration. Image credit - Dr Sissel Sjöberg — Tiny backpacks worn by noctural small birds contain a pressure sensor which provides an update every five minutes of the birds’ behaviour during migration. Image credit – Dr Sissel Sjöberg

These tags also do not provide insights into other aspects, like altitude or how they traverse over huge, inhospitable areas where they may not be able to land, like the Sahara desert or the Pacific Ocean.

Dr Sjöberg is the principal researcher of the BIRDBARRIER project which is putting tiny backpacks on nocturnal small birds migrating long distances, such as red-backed shrikes and great reed warblers. These backpacks contain an activity log with a pressure sensor to determine heights and provide updates every five minutes of their behaviour during the journey, which can be correlated with weather forecasts or detailed landscape maps.

‘It is clear they go higher in their flights then we thought before,’ said Dr Sjöberg, adding that experts previously thought their size limited them to flying at 2,000-3,000 metres above sea-level, but she has observed them fly at almost 6,000 metres.

Dr Sjöberg says they could be doing this to find stronger winds that carry them longer distances, which require less energy to fly in and increase their chances of survival.

She says the biggest risk for these birds is to stop in the hostile terrains they cross because it could be difficult to take off again or find the same heights. Safe places to land are crucial to these birds on their intercontinental journeys because they have favourable conditions, including sources of food, but in some places they are getting smaller, for instance, in the Sahara where the desert is expanding.

‘Those (safe) areas are getting smaller and smaller so there is more competition,’ said Dr Sjöberg, who will continue to collect data from the backpacks for several more months before analysing it for some new insights.

She hopes that her research will help identify the most important areas for birds, which could help inform authorities on how to better protect these safe havens.

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

This post Changing climate is narrowing options for migrating birds was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

9 September 201915 November 2019

More than a Dodo2 Comments

What colour were the dinosaurs?

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo.

What colour were the dinosaurs? If you have a picture in your head, fresh studies suggest you may need to revise it. New fossil research also suggests that pigment-producing structures go beyond how the dinosaurs looked and may have played a fundamental role inside their bodies too.

The latest findings have also paved the way for a more accurate reconstruction of the internal anatomy of extinct animals, and insight into the origins of features such as feathers and flight.

Much of this stems from investigations into melanin, a pigment found in structures called melanosomes inside cells that gives external features including hair, feather, skin and eyes their colour – and which, it now turns out, is abundant inside animals’ bodies too.

‘We’ve found it in places where we didn’t think it existed,’ said Dr Maria McNamara, a palaeobiologist at University College Cork in Ireland. ‘We’ve found melanosomes in lungs, the heart, liver, spleen, connective tissues, kidneys… They’re pretty much everywhere.’

The discoveries in her team’s newest research, published in mid-August, were made using advanced microscopy and synchrotron X-ray techniques, which harness the energy of fast-moving electrons to help examine fossils in minute detail.

Using these, the researchers found that melanin was widespread in the internal organs of both modern and fossil amphibians, reptiles, birds and mammals – following up a finding they made last year that melanosomes in the body of existing and fossil frogs in fact vastly outnumbered those found externally.

What’s more, they were surprised to discover that the chemical make-up and shape of the melanosomes varied between organ types – thus opening up exciting opportunities to use them to map the soft tissues of ancient animals.

Secondary

These studies also have further implications. For one, the finding that melanosomes are so common inside animals’ bodies may overhaul our very understanding of melanin’s function, says Dr McNamara. ‘There’s the potential that melanin didn’t evolve for colour at all,’ she said. ‘That role may actually be secondary to much more important physiological functions.’

Her research indicates that it may have an important role in homeostasis, or regulation of the internal chemical and physical state of the body, and the balance of its metallic elements.

‘A big question now is does this apply to the first, most primitive vertebrates?’ said Dr McNamara. ‘Can we find fossil evidence of this? Which function of melanin is evolutionarily primitive – production of colour or homeostasis?’

Choosing colours for dinosaur reconstructions is a combination of evidence, modern references, and artistic guesswork. Image copyright: Julius Csotonyi

At the same time, the findings imply that we may need to review our understanding of the colours of ancient animals. That’s because fossil melanosomes previously assumed to represent external hues may in fact be from internal tissues, especially if the fossil has been disturbed over time.

Dr McNamara says her research has also shown that melanosomes can change shape and shrink over the course of millions of years, potentially affecting colour reconstructions.

Further complicating the picture is that animals contain additional non-melanin pigments such as carotenoids and what is known as structural colour, which was only recently identified in fossils. In 2016, a study by Dr McNamara’s team on the skin of a 10-million-year-old snake found that these could be preserved in certain mineralised remains.

‘These have the potential to preserve all aspects of the colour-producing gamut that vertebrates have,’ said Dr McNamara.

She hopes over time that these findings and techniques will together help us to much more accurately interpret the colours of ancient organisms – though in these early days, she doesn’t have examples of animals for which this has already changed.

We’re just at the tip of the iceberg when it comes to fossil colour research.

Dr Maria McNamara, University College Cork, Ireland

Deep time

Many of the significant strides in this area have come out of a project that Dr McNamara leads called ANICOLEVO, which set out to look into the evolution of colour in animals over deep time – or hundreds of millions of years.

The project’s starting point was that previous animal colour studies largely omitted in-depth fossil analysis, leaving a significant gap by basing what we know about colour mainly on modern organisms.

But it has since led to even wider investigation. Dr McNamara says it is providing fresh hints on the kinds of biological structures and processes that are essential for survival in terrestrial and aquatic environments. ‘It looks like we’ll be able to look into much broader, exciting questions about what it means to be an animal,’ she said.

Part of her research on two fossils found in China even showed that flying reptiles known as pterosaurs had feathers, potentially taking the evolution of these structures back a further 80 million years to 250 million years ago. The fossils contained preserved melanosomes with diverse shapes and sizes, one of the tell-tale signs of feathers.

Two fossils found in China showed that flying reptiles known as pterosaurs had feathers, indicating the structures evolved earlier than previously thought. Image credit – Zixiao Yang

‘We were able to show for the first time that not only were dinosaurs feathered, but an entirely different group of animals, the pterosaurs, also had feathers,’ said Dr McNamara.

Another project she worked on, called FOSSIL COLOUR, compared the chemistry of colour patterns between fossil and modern insects. Again, says Dr McNamara, these don’t entirely map onto each other.

‘It’s already clear that the fossilisation process has altered the chemistry somewhat, so we’re doing experiments to try to understand these changes.’

What’s evident is that there’s lots still to find out about colour. ‘We’re just at the tip of the iceberg when it comes to fossil colour research,’ said Dr McNamara.

Thermoregulation

Other researchers agree that there’s more to animal colour than meets the eye. Dr Matthew Shawkey, an evolutionary biologist at Ghent University in Belgium, said that looking into properties and functions beyond colour’s use for visual means like signalling and camouflage will be critical to understanding its true significance.

‘For example, how do colours affect thermoregulation? Flight? Such functions may be complementary to, or even more significant, than purely visual functions,’ he said.

Dr Shawkey is looking into such questions, with one of his recent studies indicating that the wing colour of birds may play an important role in flight efficiency by leading to different rates of heating.

‘What started as a novelty of deciphering dinosaur colours has turned into a very serious field which is studying the origins of key pigment systems, how the evolution of colourful structures may have helped drive major evolutionary transitions like the origin of flight, and how colour is related to ecology and sexual selection,’ said Dr Steve Brusatte, a vertebrate palaeontologist and evolutionary biologist at the University of Edinburgh, UK.

Ultimately, we may be able to find out more about colour than once thought possible. ‘When I was growing up, so many of the dinosaur books I read in school said that we would never know what colour they were,’ said Dr Brusatte. ‘But as is so often the case in science, it was silly to treat this as impossible.’

He said he is excited to see what comes next, with the field just in its infancy: ‘Palaeontologists now have a whole new window into understanding the biology and evolution of long-extinct organisms.’

Top image: Aline Dassel/Pixabay, licensed under Pixabay licence

The research in this article was funded by the EU. If you liked this article, please consider sharing it on social media.

The article Fossil colour studies are changing our idea of how dinosaurs looked was originally published on Horizon: the EU Research & Innovation magazine | European Commission.

19 March 201921 March 2019

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Bacteria keep us healthy – but could they keep us young?

This article is taken from European research magazine Horizon as part of our partnership to share natural environment science stories with readers of More than a Dodo. Our Bacterial World exhibition is open until 28 May.

A study in mice has indicated that the make-up of bacteria in the gut is linked with learning abilities and memory, providing a potential avenue of research into how to maintain cognitive functioning as we age.

It’s part of a field of research looking at the link between gut bacteria and ageing to help people live healthier lives in old age. The proportion of the EU population aged 80 or over is predicted to more than double between 2017 and 2080, with those aged 65-plus rising from 20 to almost 30%.

However, the connection between the make-up of microbiota in the gut, brain functions and ageing has been unclear – with cause and effect difficult to establish. Dr Damien Rei, a postdoctoral researcher into neurodegenerative and psychiatric diseases at the Pasteur Institute in France, decided to examine the different types of microbiome that appear in younger and older mice to understand better what might happen in people too.

Coloured scanning electron micrograph (SEM) of *Escherichia coli* bacteria (red) taken from the small intestine of a child. *E. coli* are part of the normal flora of the human gut, though some strains cause illness.

He found that when he transferred gut bacteria in older mice to young adult mice, there was a strong effect on reducing learning and memory. And when the opposite was done, with older mice receiving microbiota from younger mice, their cognitive abilities returned to normal. The older mice were aged about a year and a half – equivalent to about 60-plus human years.

‘Despite being aged animals, their learning abilities were almost indistinguishable from those of young adult mice after the microbiota transfer,’ said Dr Rei – adding that this indicated strong communication between the gut and brain. ‘When I saw the data, I couldn’t believe it. I had to redo the experiment at least a couple of times.’

Furthermore, by seeing what was happening to the neuronal pathways of communication between the gut and brain when the aged microbiota was transferred to the younger mice, they were then able to manipulate these pathways. By doing this, he says they could block or mimic the effects of the aged microbiota.

Dr Rei’s study, which was carried out as part of a project called Microbiota and Aging, has not yet been published, but he hopes this could happen by the end of the summer. He is also looking into human gut microbiota in older people and those with Alzheimer’s disease, but said it is too early to reveal further details about this research.

Translating

However, Dr Rei pointed out that there is a big challenge in translating results in mice to people, not only because of the significant ethical barriers, but also the differences in physiology. ‘The immune system of a mouse is very different to one of a human. The gut microbiota is also very different because mice eat very different things to what we do,’ he said.

Research is still a long way off from making real inroads into using this type of research to combat neurodegenerative diseases such as Alzheimer’s, says Dr Rei. Indeed, he says, there is no convincing evidence yet that looking at the gut microbiota is the way to go. But he believes the mouse study opens doors to further investigation into mechanisms behind age-related changes.

‘The data on the mice was really the first stepping stone, and it was a way for us to understand the potential of manipulating the gut microbiota,’ said Dr Rei.

Pinning down the link between gut bacteria and ageing is not straightforward, according to Dr Thorsten Brach, a postdoctoral researcher at the University of Copenhagen in Denmark. ‘It’s known that ageing is a multifactorial process and it’s hard, especially when it comes to the microbiome, to separate the effects of ageing specifically from all other aspects,’ he said.

He worked on a project called Gut-InflammAge, which looked at the link between gut microbes, inflammation and ageing, led by associate professor Manimozhiyan Arumugam.

As part of their work, the team investigated the effects of mild periodic calorie restriction in mice to explore the potential impact of healthy-ageing diets involving fasting. Unexpectedly, calorie-restricted mice accumulated more body fat – which the researchers speculate may have been down to overeating between these periods – but also saw a mild ‘rejuvenation’ of their blood profile so it more closely resembled that of younger mice.

Despite being aged animals, their learning abilities were almost indistinguishable from those of young adult mice after the microbiota transfer.
Damien Rei, Pasteur Institute, France

The researchers did observe a difference between the microbiota composition in the different groups, but overall in the study the differences found were not big enough to suggest more than healthy variability between individuals. The study therefore supported the view that diet and lifestyle are more critical than age and gender in shaping the microbiota, said the researchers – though Prof. Arumugam said it would be more revealing to follow changes in individual people’s microbiomes over time.

The studies carried out so far indicate there is still a long way to go in painting an accurate picture of the link between microbiota and the ageing process. Prof. Arumugam also pointed out that microbiome analysis is lagging behind technologically compared with genetics research, with disease cause and effect harder to establish than with genes.

But research is gradually improving our understanding. Prof. Arumugam said that though his team’s study did not achieve a ‘breakthrough’, it helped give more insight into this area and raised questions over previous assumptions.

And research in this area could ultimately change how we view ageing, says Dr Rei, seeing it as more fluid than just ‘a totally one-way road with no turning back, except in the movies like Benjamin Button.’

The research in this article was funded by the EU.

Top image: Flickr/Pedro Simoes CC BY 2.0

This post Bacteria keep us healthy – but could they keep us young? was originally published on Horizon: the EU Research & Innovation magazine | European Commission.