I slip the needle through a small loop of black thread, pull it tight and snip. Done. I have just tied off the very last stitch on an embroidered scroll that has taken me more than 500 hours across 19 months to complete.

All of my artwork is extremely labour-intensive. But I have to admit, this is a bit excessive, even for me. It’s not surprising that I have been asked more than once “why not just outsource the labour?” and even “what is the point?”

I always sigh and think enviously of plumbers. I am 100% sure hardworking tradies are never asked to justify the point of their work.

Why do I work so hard? There is no one easy answer, it’s different every time. The labour intensity of my processes adds time into the equation and this both carries meaning and can change the meaning of the work as it goes on (and on and on). I always learn something unexpected.

I put my little scissors down and, before busting out the bubbles, I snap a picture for Instagram because #selfpromotion, but also because this is news, albeit of a very slow-breaking kind. This is what I’ve learned after stitching for seemingly endless hours: while no news may be good news, “slow news” is even better.

My embroidered scroll is titled Impossible Numbers. It started as my attempt to memorialise the estimated 3,000,000,000 non-human lives lost in the devastating bushfires of 2019–20, a number impossible to actually comprehend.

Doomscrolling an emergency

During that long and awful summer Sydney was often shrouded in an eerie orange haze. You could smell smoke. Ash fell. But, like many Australians, I experienced the worst of it by doomscrolling fast news.

I was both horrified and fascinated by images of fires so huge and hot they generated their own weather, by pictures of houses reduced to smoking skeletal outlines that somehow remained standing, by headlines comparing the fires to armageddon and the apocalypse.

This hyperbolic language implies we are locked in a war of good versus evil. Even headlines in the vein of “Firefighters battle blazes” pit us (people) against them (the forces of nature). And in the heat of the moment the language of war feels right. I’ve succumbed to it myself. But it is dangerous. This language reinforces the idea we can dominate nature; it frames the fires as a conflict that we can end by winning.

I will admit watching a goat-toting woman berate a sitting prime minister left me with a short-lived, but mildly satisfying, feeling of shared righteous indignation. But mostly doomscrolling just fuelled my sorrow and left me feeling impotent as, inevitably, the fast news cycled on to the next crisis (and the next, and the next).

Slowing it down

In October 2022, I finally stopped trying to process the bushfires, and all their terrifying implications, through the fast-news language of war. I picked up a needle instead.

Of course 3,000,000,000 stitches would be too many, even for me, so I decided to stitch a grid of some 15,000 squares, which I filled with innumerable stitches – a nod to the endless stream of pixels that usually deliver our news.

I started wanting to honour the 3 billion dead, that impossible number, but after months of stitching I realised I was “writing” a kind of slow-news story. It may sound ridiculous, but this tactic has been used before. The Bayeux Tapestry is a slow-news story that documents the Norman conquest of England through embroidery. It took years to stitch, and some 950 years later it is still in circulation.

As an alternative to doomscrolling easily digestible fast-news stories of good triumphing (or not) over evil, I have created an actual fabric scroll which depicts a stylised firestorm building in intensity until it becomes all-consuming.

Despite mimicking pixels, Impossible Numbers is resolutely handmade. It is too messy, too crude, to be anything else. It is bleedingly obvious (and there was blood) the will of a person is inextricably stitched into this image of devastating fire. Human labour is literally entangled in this artwork; it shows us as part of the picture, part of nature. And this is good news

Impossible Numbers doesn’t have a victorious ending, or any ending at all. The scroll is not fully unrolled. There is no end in sight: the story isn’t over, it’s ongoing.

In this way it points to the future; a future in which we are not fighting nature. And this is good news too.

If you don’t have a spare 500 hours to process the news into slow news, don’t worry. By the time I finally tied my last knot, I found I had transformed my fear and rage into something tangible, something both magnificent and beautiful (if I do say so myself), no longer about me.

It is now a slow-news story that is no longer about a particular event; something everyone can share. This is why I do the work.

Impossible Numbers is on display as part of The Blake Prize at the Casula Powerhouse, Sydney, until July 7.

This article is part of Making Art Work, our series on what inspires artists and the process of their work.

Tracey Clement, Lecturer in Visual Art and McGlade Gallery Director, Australian Catholic University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

At Cumberland City Council in the western suburbs of Sydney, one man – Councillor Steve Christou – persuaded the council to ban books about same-sex parenting from the council’s libraries.

The change was short-lived. People fought back. More than 40,000 signed a petition to lift the ban.

Only two weeks later, the Council reversed its decision, voting decisively (13-2), following impassioned pleas by residents, and with many people protesting on the streets.

Librarians under attack

Librarians are leaders in the fight against book bans. They have faced significant backlash for their efforts. Australian Library and Information Association CEO Cathie Warburton has reported that

people are going into libraries, grabbing books off the shelves, reading them out loud and saying “These shouldn’t be here”, calling librarians horrible names and threatening doxxing and physical violence. It’s incredibly distressing.

Book banning efforts are often highly coordinated. People distribute lists of books that may (or may not) be in the collections of their local libraries. These culture-war attacks on libraries and librarians are often motivated by grievances against progress, such as LGBTQ+ visibility and acceptance, and other forms of diversity.

But they are also part of a wider reactionary movement. The issues extend beyond the specific content of individual books. Calls for book bans are evidence of a broader moral panic that presents a real danger to individuals and society at large.

Libraries and librarians are common targets because they are easy for the public to access, and because they represent (and foster) learning, ideas, imagination, equality, choice and barrier-free access to information for all.

Would-be book banners have very rarely read the books they challenge. When books are read, they are far less likely to be banned.

Histories of censorship

The Cumberland episode is only the latest in the global struggle for freedom of information access. Such censorship dates back at least as far as Shakespeare. The first American book ban occurred in 1637, when Thomas Morton’s New English Canaan was suppressed for its criticisms of Puritanism.

The issue remains highly contentious in the United States. PEN America’s latest report shows a 33% rise in the number of book challenges in US public schools, with almost 6,000 instances of books banned since 2021.

The Alabama House of Representatives recently passed Bill HB385. If it passes the Senate, the bill will override libraries’ book challenge policies. Librarians would have seven days to remove contentious material or face criminal penalties.

Australia also has a long history of censorship. Many titles we now consider “classics” faced bans, including Aldous Huxley’s Brave New World, James Baldwin’s Another Country and D.H. Lawrence’s Lady Chatterley’s Lover. As literary historian Nicole Moore documented, it was once “routine to have your suitcase searched [for obscene materials] on the way into Australia from another country”.

More recently, in March 2023, Maia Kobabe’s award-winning memoir Gender Queer was removed from a Queensland library, and faced many other challenges, globally. Bernard Gaynor, the conservative Catholic activist who led the call to ban the book, is taking the Minister for Communication and the Australian Classification Review Board to the Federal Court of Australia. The decision will come later this year.

Censorship remains a local – and global – concern.

Information access for all

Professional librarians have battled these kinds of challenges for decades. The American Library Association, founded in 1876, issued its first anti-censorship notice in 1939, in response to Nazi book burning and other international attempts to suppress information.

In 1953, the American Library Association issued their Freedom to Read statement, with ongoing support for libraries challenging book bans across the United States.

In a joint statement, the Australian Library and Information Association and the Australian Public Library Alliance explain that libraries “defend equity of access to information” and “cater for all members of the library community”.

This position reflects global standards for information access upheld by libraries worldwide. It includes the key principle that the “perception that material may offend or cause controversy to a person or a group of people is not, of itself, a reason to limit purchase or provision of an item containing that material”.

The International Federation of Library Associations states that censorship “runs counter to Article 19 of the Universal Declaration of Human Rights”. Libraries are expected to:

• provide collections and services that are free of intentional censorship

• base decisions on professional considerations (e.g., quality, currency, format, cost, etc.), rather than limiting based on political or religious considerations or cultural prejudice

• educate people on issues of censorship and encourage them to practise freedom of expression and freedom of access to information

• advocate for removal of censorship restrictions affecting libraries and society at large.

Policies and procedures

Librarians do more than handle attempts to ban books. They develop policies and procedures designed to ensure free access to information, for everyone. They are expert professionals, whose jobs often require difficult selection decisions and challenging conversations with angry or offended community members.

Libraries already have established processes to handle removal requests. They apply guidance from professional associations, including resources like the Selection & Reconsideration Policy Toolkit for Public, School, & Academic Libraries.

Requests to remove materials often start with informal conversations to address concerns and educate complainants about the library’s mandate for equitable access based on the whole community’s needs and interests. A formal process often requires a written submission. Library staff will then reconsider the book in light of the library’s collection policy.

Removing books from a collection does happen, as librarians must ensure the collection remains useful and relevant. Libraries routinely consult with community members and seek feedback to ensure collections match community needs. They also review materials to ensure outdated works (for example, older editions) are replaced with texts that include current information.

These are some of the routine, behind-the-scenes tasks, which collections librarian Scarlet Galvan explains are critical to ensure “collections are for use, not reinforcing assumptions”.

The need for community involvement

Librarians rely on individuals and communities to stand up and oppose censorship, as residents did in Cumberland. Vocal community and government support for libraries is critical to battling book bans. Many other professions, such as journalism and teaching, also play critical roles in documenting censorship and countering book challenges.

So how can you help? By signing petitions, speaking up at council meetings, volunteering to serve on a library board, voting for candidates who support libraries, and borrowing books about diverse families to ensure they have a circulation record of being used and valued.

As the outcry over the short-lived Cumberland City Council ban shows, everyday Australians value libraries and the information they provide to their communities. Public support is needed to defend against future attacks and to send a message to governments that banning books is not acceptable.

Lisa M. Given, Professor of Information Sciences & Director, Social Change Enabling Impact Platform, RMIT University and Sarah Polkinghorne, Research Fellow, Social Change Enabling Impact Platform, RMIT University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The largest field of pyramids in Egypt – consisting of 31 pyramids built over a millennium, including the famous Great Pyramid at Giza – lies along a narrow strip of land in the desert several kilometres west of the Nile River.

The Nile was at the heart of ancient Egyptian civilisation, and the location of so many pyramids some distance away from the river has until now not been fully explained.

In a new study published in Communications Earth & Environment, we addressed this puzzle. When the pyramids were built they sat next to a now-vanished branch of the Nile, which likely provided transport for workers and their materials.

A changing river

Like other rivers, the Nile adjusts and changes over time in response to climate change, floods and droughts. People and places also move with the river. In the past, civilisations fell and rose on its ebb and flow.

The Nile has not always looked or functioned the way it does now. By reading the landscape in Egypt, traces of the former river and its branches can be found hidden just beneath the land surface.

Now obscured by areas of cultivation and urban settlements, buried by centuries of mud from the modern river, the old channels and their stories have largely been lost to time. Once a mosaic of waterways and wetlands, the Nile is ready to share its secrets again.

Many scholars have discussed and sought answers to the mysteries of the Nile. Previous research has documented evidence for the existence of parts of ancient waterways or wetlands, particularly near the Giza pyramids.

Upstream near Luxor, Nile migration patterns have been investigated, and downstream abandoned channels have been discovered in the Nile Delta. Yet until now we did not have a comprehensive map and understanding of the waterways that fed the extensive pyramid chain from Lisht to Giza in the past.

The Ahramat Branch

Using satellite imagery, high-resolution digital elevation data and historical maps, we identified and traced the long path of a previously unknown channel of the Nile. What we have called the Ahramat Branch once flowed along the Western Desert margin of the Nile floodplain, close to the ancient pyramids.

Many of the pyramids, built during the Old Kingdom (roughly 2700–2200 BCE) and the Middle Kingdom (2050–1650 BCE), have causeways that lead to the branch. Many of these paths terminate in temples that may have acted as river docks in the past.

This suggests the Ahramat Branch was active during multiple phases of pyramid construction and was probably used as a transportation waterway for workmen and building materials to the sites.

Some pyramids have longer or differently angled causeways than others, indicating the builders adapted their construction approaches to the changing riverscape and local conditions at the desert margin.

Other pyramids were connected to inlets associated with tributaries of the Ahramat Branch on the edge of the Western Desert. In all, analysis of the ground elevation of 31 pyramids and their proximity to the floodplain helped explain the position and relative water level of the Ahramat Branch during the time between the Old Kingdom and the Second Intermediate Period (roughly 2649–1540 BCE).

Digging deep

Once we had mapped the Ahramat Branch, we surveyed the landscape and its shape, and took deep core samples of soil and sediment to study the structure and sedimentology of the former river. We also worked with archaeologists, scientists and members of local communities to gather more context for our work.

The path of the defunct waterway lies between 2.5 and 10.25 kilometres west of the modern Nile river.

Our research suggests the branch ran for about 64 kilometres, was between two and eight metres deep, and between 200 and 700 metres wide. This is similar to the width of the river today.

At one of the sites we examined, near the town of Jirzah, the Ahramat Branch has a symmetrical channel shape. It has also been filled in with muddy and sandy sediment different to other surrounding deposits and the underlying bedrock. This indicates that the old channel has been slowly buried by fine sediment deposited by floods, as the main flow diverted towards the path of the modern river.

What happened to the Ahramat Branch?

Over time, the Ahramat Branch moved eastward and eventually water stopped flowing along it. We don’t know exactly why. Perhaps the Ahramat Branch and its daughter, the modern river, were active together for a time.

The river may have gradually moved to the lower-lying floodplain, towards the current location of the Nile. It is also possible that tectonic activity tilted the whole floodplain to the northeast.

A third possibility is that an increase in windblown sand may have filled up the river’s channel. Increases in sand deposition are most likely related to periods of desertification in the Sahara desert in North Africa.

The movement and diminishing of the Ahramat Branch might also be explained by an overall reduction in water flow due to reduced rainfall and greater aridity in the region, particularly during the end of the Old Kingdom.

This research shows that a multidisciplinary approach to river science is needed to gain a better understanding of dynamic river landscapes. If we want to understand and protect the rivers we have today – and the environmentally and culturally significant sites to which they are inextricably tied – we need a greater appreciation of the interconnected factors that affect rivers and how they can be managed.

Timothy J. Ralph, Associate Professor, Macquarie University; Eman Ghoneim, Professor and Director of Space and Drone Remote Sensing Lab, University of North Carolina Wilmington, and Suzanne Onstine, Associate Professor, Department of History, University of Memphis

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Our family dog used to have a rather noticeable extra eyelid that became especially apparent when he dozed off, usually upturned on the rug. This is the fleshy curtain seen at the corner of each eye, closest to the nose. It’s also commonly called the nictitating (literally “blinking”) membrane.

You may have noticed these “third” eyelids on your pets appear occasionally, perhaps during their sleepy moments, or when they’re enjoying a bit of affection. But what does this unusual structure actually do? And why don’t we have one as well?

Third eyelids sweep in a generally horizontal direction across the eye, instead of vertically as the upper and lower lids do. They’re actually a specialised fold of the conjunctiva – the thin, moist membrane that coats the other lids and the exposed white of your eye (the sclera). They’re found in many mammalian species, but are not unique to them. Birds, reptiles, amphibians and fish can also have a third eyelid.

The structure varies too; in many species a cartilage skeleton provides support, while others contain glands that secrete tears. This variation is probably to help animals adapt to multiple different environments – to the sea, the air and even arboreal habitats in trees.

Several different studies have examined third eyelids to help understand their role in hedgehogs, kangaroos and brown bears.

And research has shown the third eyelid functions much as the upper and lower lids do. It protects the eye, and sweeps away any invading debris. It also distributes tears across the eye’s surface, keeping it moist and preventing ulcers forming. This is particularly important in brachycephalic (flat-faced) dogs, like pugs and King Charles spaniels, whose protruding eyes are not as well protected compared to other breeds.

In the wild

Both domestic and wild animals (including species from canine, feline and equine families) need eye shielding and protection from foreign bodies. Wild animals may need them even more, since they might be exploring grasslands, or contending with bites and scratches from prey or rival animals.

Preventing, trapping and removing debris is crucial for desert animals like camels, where sand and dirt might damage the eye. Their third eyelid is partially transparent and this helps camels retain some vision in the middle of a sandstorm, while covering their eyes.

In bushlands, aardvarks also have third eyelids, perhaps to protect their eyes as they root around for insects.

The third eyelid may offer protection from water, and a translucent membrane can aid underwater vision of aquatic animals, including manatees (curiously, manatees come from the order Afrotheria, which also includes aardvarks). Larger species of sharks (blues for instance) typically protect their eyes with their third eyelid when hunting and feeding.

For birds, fast air currents can prove equally damaging. So, in birds of prey like falcons, the eyelid is used during rapid flight in hunting. Often air gusts will set off third eyelid blinking in these birds (including owls) as a natural protective reflex.

In other avian species, it might protect against damage from sharp-beaked offspring. Imagine a bird returning with a prize of food to a nestful of voraciously hungry chicks, all pecking and scrabbling to get their share.

Studies suggest third eyelids play a unique role in woodpeckers, whose skulls undergo vibration trauma when drilling a tree trunk with their beak. Two problems arise as a result of this forceful head banging – damage to the softer eye tissue, and sawdust being thrown into them. In this case, the third eyelid may act as both a seatbelt and a visor.

In polar regions, where the white landscape reflects sunlight, ultraviolet rays can damage the eye. This can lead to temporary loss of vision – a condition known as snow blindness. So it’s possible that some arctic animals like polar bears have third eyelids that absorb UV light. There’s no established evidence of this yet, but their third eyelids are clear, assisting them in being skilled marine hunters.

Evolutionary loss

Humans and most primates (except lemurs and the calabar angwantibo, from the Lorisidae family) have evolved to the point where a proper third eyelid is no longer needed. Human and primate eyes are less likely to be damaged by hunting, rivalry and the environment. Plus, human eyes are highly sensitive and able to recognise and respond to danger by closing more quickly.

But the third eyelid isn’t entirely gone. Humans have a remnant of it called the plica semilunaris. This crescent-moon fold can be seen at the corner of our eyes too. Have a look yourself in the mirror.

Some scientists have argued the plica can still help drain tears. There are two small ducts at the angle of our eyelids, which allow excess and old tears to escape into the nasal cavity. That explains why you get a runny nose when you cry.

But would getting our true third eyelid back be of any use to us? Maybe the alien in Men in Black could offer an opinion. Perhaps it could allow us to naturally keep our eyes cleaner, less irritated, or dislodge that contact lens that won’t come out.

We’ll just have to accept we don’t share the clever nature of our pets’ third eyelids. But then we also can’t compete with their night vision, acute hearing or sense of smell. It’s a long list.

Dan Baumgardt, Senior Lecturer, School of Physiology, Pharmacology and Neuroscience, University of Bristol

This article is republished from The Conversation under a Creative Commons license. Read the original article.

In one sense, Let It Be director Michael Lindsay-Hogg’s 1970 film documenting The Beatles’ recording sessions of January 1969, and their famous concert on the rooftop of the Apple building, could be viewed as something of a coda to the main event.

At the time, both the film and the accompanying album of the same name reached the public a month after the band’s break up was announced. In the present day, its rerelease follows Peter Jackson’s epic Get Back docuseries, which drew on the 60 hours of raw footage of the same sessions to provide a more complete account of the recordings.

So, why the fuss? Rereleases and remasters are a standard feature of both the film and music industries, and The Beatles’ media and commercial juggernaut has arguably led the way in this for a long time. First, there’s the sheer length of time since the film was last generally available – more than 50 years.

The answer also partly lies in the distinctive way in which, beyond their huge financial success, the narrative of The Beatles as a band has been woven into popular music and wider history. Peter Jackson’s 2020 series in many respects superseded Hogg’s film, providing a fuller picture of the sessions, which also fed into the Abbey Road album, the band’s last recording (even though Let It Be was released afterwards).

Same events, different perspectives

A highlight of both the film and series was the concluding rooftop concert, but Jackson’s programme was widely acknowledged for adding context to the band’s closing chapter. The hours of jamming and studio high-jinks revealed moments of camaraderie and a less rancorous atmosphere than had previously been thought.

So, beyond the events themselves, there’s an element of historiography at play here – a concern with how history is written and constructed. Since Let It Be’s original release, The Beatles have become an increasingly important aspect of popular music, and wider social history. Beyond the mystique acquired by inaccessibility for so long, the film gains interest as a document of how the band’s last days as an active unit were framed, and experienced, at the time.

In purely functional terms, it’s obviously easier to give a more complete account of the recording sessions in the nearly eight hours afforded by Peter Jackson’s Get Back than the one and a half hours available to Lindsay-Hogg on Let It Be.

Moments of discord appear in both, notably the famous encounter between a taciturn George Harrison – who walked out during the sessions – telling a cajoling Paul McCartney, about a guitar part: “I’ll play, you know, whatever you want me to play. Or I won’t play at all, if you don’t want me to play.”

These are diluted in the long stretch of Get Back, but become part of the central narrative of Let It Be. Filmmakers’ editorial decisions shape their stories, but are informed by their own contexts. Lindsay-Hogg was editing the film at a time when the band had just split, and trying to salvage a viable product from a somewhat chaotic process, since he’d originally been taken on to produce a television documentary and concert broadcast.

Re-tooling it as a film was a response to the band dropping the idea of a major event, the now legendary rooftop performance only emerging as a process of back and forth compromise.

Conversely, one of the iconic elements of Jackson’s Get Back series shows Paul McCartney coming up with the bare bones of the song of the same name more or less impromptu, and the pleasure in seeing how it develops. But that relies on the more leisurely pacing of the long form allowed by primary release on a streaming platform, as opposed to the editorial constraints of a cinema (or even television) release.

The streaming format was, of course, a long way off in the future when Lindsay-Hogg was working with the band. Jackson’s series also works more profoundly because of the classic status Get Back (the song) has accrued over half a century. For Lindsay-Hogg filming in 1969, it was just another jam – albeit by the world’s most famous band. In 2020, much of the audience was witnessing the genesis of a song they’d known their whole lives.

Framing popular music history

Get Back reviews the longitudinal process of a band at work, and one whose working processes had influenced many of the acts that followed in their wake. The Beatles’ success helped to shape the very idea of a band combining multiple songwriters and friends into a social, creative and business unit.

Their split was big news, and mattered in a way that the re-combinations of musicians into new working units had not done previously. Let It Be was tied into that historical moment, and the presence in the room of Lindsay-Hogg’s cameras helped to define it.

Viewed at the arrival of the 1970s, as the preeminent band of the 1960s announced their demise, Let It Be told the story of an ending, enhanced by the technical fact that it was blown up from a 16mm print, for TV, to 35mm for the cinema, adding a dark, grainy patina to the proceedings, now alleviated in the remastering process.

Now in 2024, it’s a document in a wider archive of Beatles lore and helps to inform the process of how the history of popular music is written.

Adam Behr, Senior Lecturer in Popular and Contemporary Music, Newcastle University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

One of the wildest wonders of nature is the ability of some animals to reproduce by splitting in half. There is still so much we don’t know about this process. So the discovery of a 155-million-year-old starfish fossil frozen partway through this process, published in a new study, could give scientists incredible new insights.

Our planet is teeming with invertebrates that, to our human eyes, may seem alien in the way they live and reproduce.

The starfish, or asteroid, is part of a group of animals called the echinoderms or spiny skinned animals that also includes sea lilies, sea urchins and sea cucumbers. They are found in almost every corner of our oceans and spend part of their life as microscopic larvae before developing into adults.

Starfish are among the oldest living animals on our planet. They appeared in a form we would recognise almost 480 million years ago and have survived five mass extinctions.

The reason for their evolutionary success could be in their ability to reproduce both sexually and asexually – by literally splitting in two and growing into two new animals. This is known as fissiparity. It is still sometimes observed in modern starfish and comes with the advantage of forming numerous offspring in a relatively short time and without “costing” the parent a great amount of energy or time.

Sexual reproduction, on the other hand, requires starfish and brittle stars to come together in huge numbers to spawn. The disadvantage of fissiparity is that this type of reproduction can result in a lack of genetic diversity in the population.

Biologists call the process of splitting in two parts fragmentation. Only a small number of animals can do this. For example, the common garden earthworm, which many gardeners have watched in amazement as one animal suddenly becomes two. Biologists can also watch starfish and brittle stars doing this in their labs or in marine stations.

But, until now, scientists weren’t sure how old this form of reproduction was. This phenomenon is most often seen in worm-like animals, and worm fossils are rare.

However, starfish can also split in two and have a much better fossil record. These animals still dominate our oceans, the deep seas are a carpet of them.

Rebirth of a fossil star

In the past ten years, Ben Thuy, a palaeontologist, has revolutionised the way we look at the evolution and biology of a group of starfish-like animals called the brittle stars or ophiuroids.

First by looking at how these animals have evolved, survived and then thrived in response to mass extinction events or ecological pressure. His work, studying the way their skeleton is made up of calcite plates, has changed our view of not only how the modern brittle star body shape appeared in the fossil record but also how we classify these animals.

In palaeontology, we are always searching for that key fossil that radically changes our view of how life evolved and developed on this planet. For example, the 2021 discovery of 480-million-year-old starfish-like animals in the Anti-Atlas mountains in Morocco helped us understand how these animals first appeared.

Such fossils are the holy grail of palaeobiology. They can give us a snapshot of the history of life and show us the moment a new animal first evolved on our planet.

Only a few animals make it into the fossil record, and many of these are in fragments as they often fall apart once the body has decayed. However, Thuy’s brittle star discovery appears to show a brittle star in the process of reproducing asexually. The fossil has already been “born”. One half of the body appears to be fully developed while the other half shows signs of regeneration with three smaller arms clearly visible.

This discovery means that we know that these animals were reproducing in this way 90 million years before the asteroid collision that wiped out the dinosaurs.

Scientists don’t always agree on what a fossil shows. There is a chance the brittle star fossil is a new species or an unusual individual that happens to have six arms rather than the typical five.

There are many examples of starfish that have more than five arms, including species such as Coscinasterias calamaria or 11 armed starfish. They can also gain an extra arm through natural genetic variation in the population similar to eye colour in humans.

But the study authors used comparative studies of other brittle stars that appear to have undergone regeneration to argue that their fossil originally had six arms before it split in two. Therefore, the authors say, the fossil must be the result of clonal fragmentation and the first in the fossil record.

If they’re right, fossils have allowed us to see the moment a new starfish was born in deep time.

Aaron W. Hunter, Science Guide & Visiting Researcher, Earth Sciences, University of Cambridge

This article is republished from The Conversation under a Creative Commons license. Read the original article.

For nearly 200 years, Florence Nightingale’s name has been synonymous with gentle compassion and mercy.

In the mid-19th century, Nightingale became perhaps the most celebrated woman of her era – second only to Queen Victoria – for instituting sanitation practices that sharply cut death rates among British soldiers fighting in the Crimean War. A handsome bronze statue in London’s Waterloo Place has immortalized Nightingale as a slight, graceful figure carrying a lamp, the embodiment of selfless womanhood.

But this iconic image overshadows many other accomplishments. Nightingale also transformed nursing into a respectable profession, founded the world’s first nursing school, used the relatively new science of statistics to improve health care outcomes and redesigned hospitals. She was also one of Western history’s first advocates of health care for all.

Over the five years I spent researching and writing my biographical novel about Nightingale, “Flight of the Wild Swan,” published March 12, 2024, my vaguely sentimental notions about her were replaced by respect for her visionary achievements. I resolved to bring into sharper focus this woman who, along with her legendary work as a war nurse, spent half a century pioneering advances in health care.

The 19th century ushered in a series of revolutionary medical advancements. Nightingale’s contributions were a significant part of this era.

Called to serve the suffering

Florence Nightingale was born in Florence, Italy, on May 12, 1820, to William and Frances Nightingale, a wealthy British couple. The Nightingales raised their two daughters, Florence and her sister Parthenope, on two estates in England. William homeschooled the girls, giving them the equivalent of his own Cambridge University education.

From an early age, Nightingale displayed a formidable intellect, with a particular interest in mathematics. At 16, she experienced a transcendent call to serve the suffering, a call that eventually coalesced into her determination to become a nurse. Her family objected, however, because nursing was an unsuitable occupation for young Victorian women of privilege. It was considered disreputable work with a status even lower than that of servants.

But Nightingale gradually overcame her family’s objections, receiving training in Germany and France. In 1853, she became the superintendent of a small hospital in London for “distressed gentlewomen.” The majority of her patients were educated, unmarried governesses whose health had broken down under the strain of long hours of work and negligible pay.

A little over a year later, she was on her way to the Crimean War.

Bringing sanitation to medicine

In October 1854, Nightingale brought 38 female nurses under her supervision to Scutari Barrack in Constantinople – today’s Istanbul. Originally a gargantuan stone barracks for the Turkish army, Scutari was now a British hospital housing thousands of wounded English and Irish soldiers.

At Scutari, she and her nurses found few provisions, little medicine or edible food, and overcrowded hospital wards full of rats, lice and raw sewage. More soldiers were dying of cholera and other infectious diseases than of battle wounds. Nightingale and her nurses set to work cleaning and procuring food, soap, bandages, medicine, clean bedding and clothes for patients. As living standards improved, Scutari’s appalling death rate began to decline.

It was there that Nightingale’s reputation as the “Angel of the Crimea” and the “Lady with the Lamp” began. Wartime journalists telegraphed their newspapers with dramatic accounts of her work. These stories ignited the public’s imagination and created the indelible image of a slight, feminine figure carrying her lamp through hospital wards at night.

In January 1855, British Prime Minister Henry John Temple, 3rd Viscount Palmerston, dispatched a newly formed Sanitary Commission to the Crimea to investigate high mortality rates in the military hospital. Nightingale observed firsthand the dramatic decline in death rates as the commission cleaned out the hospital’s befouled sewer systems, limewashed its walls – in effect killing surface bacteria – and made numerous other sanitation improvements.

Nightingale was already a proponent of hygiene, fresh air and proper diet in medical care; this experience made her a committed sanitarian.

When the war ended in 1856, Nightingale returned home, permanently bedridden with chronic brucellosis, then called “Crimean fever.” This didn’t stop her from spending the rest of her life applying herself to improving health care systems in Great Britain and other countries.

Using numbers to cure

Statistics was a relatively new science in Nightingale’s time, but it aligned with her early interest in mathematics. Ultimately, Nightingale would come to believe that statistics used to help reduce mortality rates were “the true measure of God’s purpose.”

Collaborating with William Farr, a leading figure in applying statistics to epidemiology, Nightingale analyzed extensive data on army mortality rates during the Crimean War, proving that most deaths were attributable to preventable diseases rather than battlefield injuries. She was particularly innovative in her use of graphic diagrams such as her famous “rose,” or “coxcomb,” diagram, rightly believing that attractive visuals were more impactful than the dry numbers tables favored by the era’s statisticians.

As a result, in 1858, in recognition of her use of the statistical method in army sanitary reform, Nightingale was inducted into the Royal Statistical Society as the organizations’s first female fellow. In 2020, the Royal Statistical Society established an annual Florence Nightingale Award for Excellence in Health and Care Analytics.

In a revolutionary step, Nightingale extended her statistical methods and data visualization to other areas, ranging from hospital administration and health care management to public sanitary reform and the sources of preventable diseases. These analyses further exposed the causes of both military and civilian mortality.

Educating future nurses

In 1860, seeking to elevate nursing into both a science and an art, Nightingale founded the world’s first school of nursing: the Nightingale Training School for Nurses at St. Thomas’ Hospital, London.

The female students – numbering 20 to 30 at a time – lived at school and wore nurses’ uniforms to rigorous classes on anatomy, surgical nursing, physiology, chemistry, sanitation and ethics. By the 1880s, Nightingale had accepted the newer “germ theory” of disease spread, and this became part of the curriculum.

At the conclusion of the one-year program, Nightingale sent her nurses into the world as certified and paid health professionals.

By the turn of the century, the school had graduated nearly 2,000 certified nurses. Known as “Nightingales,” they fanned out across Great Britain to practice skilled patient care, develop nursing care systems, teach, train and mentor.

The Nightingale Training School became a pioneering model for nursing education throughout Great Britain. Similar schools would be established in Africa, America, Australia, Canada and other countries.

Nightingale also wrote a bestselling book, 1859’s “Notes on Nursing,” that guided Victorian wives in keeping members of their households healthy.

Advocating for public health

Nightingale’s long, ultimately successful effort to bring trained nurses and midwives into England’s and Ireland’s notorious workhouses has gone largely unacknowledged.

During Victorian times, paupers in workhouses who became ill could be cared for only by other destitute workhouse residents. Nightingale wrote numerous articles emphasizing the need for public health nurses to care of the sick in these institutions, and during the 1860s she called for the abolition of England’s harsh poor laws.

As a result of these efforts, workhouse nursing reforms gradually spread across England.

I believe that a more fully realized understanding of Nightingale’s life and achievements beyond being “the lady with the lamp” can provide an inspirational role model for those considering careers in nursing, medical science and public health today.

Melissa Pritchard, Professor Emeritus of English and Women’s Studies, Arizona State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Physicists consider black holes one of the most mysterious objects that exist. Ironically, they’re also considered one of the simplest. For years, physicists like me have been looking to prove that black holes are more complex than they seem. And a newly approved European space mission called LISA will help us with this hunt.

Research from the 1970s suggests that you can comprehensively describe a black hole using only three physical attributes – their mass, charge and spin. All the other properties of these massive dying stars, like their detailed composition, density and temperature profiles, disappear as they transform into a black hole. That is how simple they are.

The idea that black holes have only three attributes is called the “no-hair” theorem, implying that they don’t have any “hairy” details that make them complicated.

Hairy black holes?

For decades, researchers in the astrophysics community have exploited loopholes or work-arounds within the no-hair theorem’s assumptions to come up with potential hairy black hole scenarios. A hairy black hole has a physical property that scientists can measure – in principle – that’s beyond its mass, charge or spin. This property has to be a permanent part of its structure.

About a decade ago, Stefanos Aretakis, a physicist currently at the University of Toronto, showed mathematically that a black hole containing the maximum charge it could hold – called an extremal charged black hole – would develop “hair” at its horizon. A black hole’s horizon is the boundary where anything that crosses it, even light, can’t escape.

Aretakis’ analysis was more of a thought experiment using a highly simplified physical scenario, so it’s not something scientists expect to observe astrophysically. But supercharged black holes might not be the only kind that could have hair.

Since astrophysical objects such as stars and planets are known to spin, scientists expect that black holes would spin as well, based on how they form. Astronomical evidence has shown that black holes do have spin, though researchers don’t know what the typical spin value is for an astrophysical black hole.

Using computer simulations, my team has recently discovered similar types of hair in black holes that are spinning at the maximum rate. This hair has to do with the rate of change, or the gradient, of space-time’s curvature at the horizon. We also discovered that a black hole wouldn’t actually have to be maximally spinning to have hair, which is significant because these maximally spinning black holes probably don’t form in nature.

Detecting and measuring hair

My team wanted to develop a way to potentially measure this hair – a new fixed property that might characterize a black hole beyond its mass, spin and charge. We started looking into how such a new property might leave a signature on a gravitational wave emitted from a fast-spinning black hole.

A gravitational wave is a tiny disturbance in space-time typically caused by violent astrophysical events in the universe. The collisions of compact astrophysical objects such as black holes and neutron stars emit strong gravitational waves. An international network of gravitational observatories, including the Laser Interferometer Gravitational-wave Observatory in the United States, routinely detects these waves.

Our recent studies suggest that one can measure these hairy attributes from gravitational wave data for fast-spinning black holes. Looking at the gravitational wave data offers an opportunity for a signature of sorts that could indicate whether the black hole has this type of hair.

Our ongoing studies and recent progress made by Som Bishoyi, a student on the team, are based on a blend of theoretical and computational models of fast-spinning black holes. Our findings have not been tested in the field yet or observed in real black holes out in space. But we hope that will soon change.

LISA gets a go-ahead

In January 2024, the European Space Agency formally adopted the space-based Laser Interferometer Space Antenna, or LISA, mission. LISA will look for gravitational waves, and the data from the mission could help my team with our hairy black hole questions.

Formal adoption means that the project has the go-ahead to move to the construction phase, with a planned 2035 launch. LISA consists of three spacecrafts configured in a perfect equilateral triangle that will trail behind the Earth around the Sun. The spacecrafts will each be 1.6 million miles (2.5 million kilometers) apart, and they will exchange laser beams to measure the distance between each other down to about a billionth of an inch.

LISA will detect gravitational waves from supermassive black holes that are millions or even billions of times more massive than our Sun. It will build a map of the space-time around rotating black holes, which will help physicists understand how gravity works in the close vicinity of black holes to an unprecedented level of accuracy. Physicists hope that LISA will also be able to measure any hairy attributes that black holes might have.

With LIGO making new observations every day and LISA to offer a glimpse into the space-time around black holes, now is one of the most exciting times to be a black hole physicist.

Gaurav Khanna, Professor of Physics, University of Rhode Island

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Scientific discovery doesn’t always require a high-tech laboratory or a hefty budget. Many people have a first-rate lab right in their own homes – their kitchen.

The kitchen offers plenty of opportunities to view and explore what physicists call soft matter and complex fluids. Everyday phenomena, such as Cheerios clustering in milk or rings left when drops of coffee evaporate, have led to discoveries at the intersection of physics and chemistry and other tasteful collaborations between food scientists and physicists.

Two students, Sam Christianson and Carsen Grote, and I published a new study in Nature Communications in May 2024 that dives into another kitchen observation. We studied how objects can levitate in carbonated fluids, a phenomenon that’s whimsically referred to as dancing raisins.

The study explored how objects like raisins can rhythmically move up and down in carbonated fluids for several minutes, even up to an hour.

An accompanying Twitter thread about our research went viral, amassing over half a million views in just two days. Why did this particular experiment catch the imaginations of so many?

Bubbling physics

Sparkling water and other carbonated beverages fizz with bubbles because they contain more gas than the fluid can support – they’re “supersaturated” with gas. When you open a bottle of champagne or a soft drink, the fluid pressure drops and CO₂ molecules begin to make their escape to the surrounding air.

Bubbles do not usually form spontaneously in a fluid. A fluid is composed of molecules that like to stick together, so molecules at the fluid boundary are a bit unhappy. This results in surface tension, a force which seeks to reduce the surface area. Since bubbles add surface area, surface tension and fluid pressure normally squeeze any forming bubbles right back out of existence.

But rough patches on a container’s surface, like the etchings in some champagne glasses, can protect new bubbles from the crushing effects of surface tension, offering them a chance to form and grow.

Bubbles also form inside the microscopic, tubelike cloth fibers left behind after wiping a glass with a towel. The bubbles grow steadily in these tubes and, once they’re big enough, detach and float upward, carrying gas out of the container.

But as many champagne enthusiasts who put fruits in their glasses know, surface etchings and little cloth fibers aren’t the only places where bubbles can form. Adding a small object like a raisin or a peanut to a sparkling drink also enables bubble growth. These immersed objects act as alluring new surfaces for opportunistic molecules like CO₂ to accumulate and form bubbles.

And once enough bubbles have grown on the object, a levitation act may be performed. Together, the bubbles can lift the object up to the surface of the liquid. Once at the surface, the bubbles pop, dropping the object back down. The process then begins again, in a periodic vertical dancing motion.

Dancing raisins

Raisins are particularly good dancers. It takes only a few seconds for enough bubbles to form on a raisin’s wrinkly surface before it starts to rise upward – bubbles have a harder time forming on smoother surfaces. When dropped into just-opened sparkling water, a raisin can dance a vigorous tango for 20 minutes, and then a slower waltz for another hour or so.

We found that rotation, or spinning, was critically important for coaxing large objects to dance. Bubbles that cling to the bottom of an object can keep it aloft even after the top bubbles pop. But if the object starts to spin even a little bit, the bubbles underneath make the body spin even faster, which results in even more bubbles popping at the surface. And the sooner those bubbles are removed, the sooner the object can get back to its vertical dancing.

Small objects like raisins do not rotate as much as larger objects, but instead they do the twist, rapidly wobbling back and forth.

Modeling the bubbly flamenco

In the paper, we developed a mathematical model to predict how many trips to the surface we would expect an object like a raisin to make. In one experiment, we placed a 3D-printed sphere that acted as a model raisin in a glass of just-opened sparkling water. The sphere traveled from the bottom of the container to the top over 750 times in one hour.

The model incorporated the rate of bubble growth as well as the object’s shape, size and surface roughness. It also took into account how quickly the fluid loses carbonation based on the container’s geometry, and especially the flow created by all that bubbly activity.

The mathematical model helped us determine which forces influence the object’s dancing the most. For example, the fluid drag on the object turned out to be relatively unimportant, but the ratio of the object’s surface area to its volume was critical.

Looking to the future, the model also provides a way to determine some hard to measure quantities using more easily measured ones. For example, just by observing an object’s dancing frequency, we can learn a lot about its surface at the microscopic level without having to see those details directly.

Different dances in different theaters

These results aren’t just interesting for carbonated beverage lovers, though. Supersaturated fluids exist in nature, too – magma is one example.

As magma in a volcano rises closer to the Earth’s surface, it rapidly depressurizes, and dissolved gases from inside the volcano make a dash for the exit, just like the CO₂ in carbonated water. These escaping gases can form into large, high-pressure bubbles and emerge with such force that a volcanic eruption ensues.

The particulate matter in magma may not dance in the same way raisins do in soda water, but tiny objects in the magma may affect how these explosive events play out.

The past decades have also seen an eruption of a different kind – thousands of scientific studies devoted to active matter in fluids. These studies look at things such as swimming microorganisms and the insides of our fluid-filled cells.

Most of these active systems do not exist in water but instead in more complicated biological fluids that contain the energy necessary to produce activity. Microorganisms absorb nutrients from the fluid around them to continue swimming. Molecular motors carry cargo along a superhighway in our cells by pulling nearby energy in the form of ATP from the environment.

Studying these systems can help scientists learn more about how the cells and bacteria in the human body function, and how life on this planet has evolved to its current state.

Meanwhile, a fluid itself can behave strangely because of a diverse molecular composition and bodies moving around inside it. Many new studies have addressed the behavior of microorganisms in such fluids as mucus, for instance, which behaves like both a viscous fluid and an elastic gel. Scientists still have much to learn about these highly complex systems.

While raisins in soda water seem fairly simple when compared with microorganisms swimming through biological fluids, they offer an accessible way to study generic features in those more challenging settings. In both cases, bodies extract energy from their complex fluid environment while also affecting it, and fascinating behaviors ensue.

New insights about the physical world, from geophysics to biology, will continue to emerge from tabletop-scale experiments – and perhaps from right in the kitchen.

Saverio Eric Spagnolie, Professor of Mathematics, University of Wisconsin-Madison

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Collectors relish so-called “hidden mother photographs” as historical oddities.

These 19th-century images contain very young children held still by half-obscured adults who crouch behind chairs or lurk at the margins of pictures, their protective arms stabilizing babies. The heads and shoulders of the adults are sometimes draped in textiles or summarily cut off, or their bodies are partially tucked behind decorative mats that frame the centered child.

The startling realization that Victorian infants were not reclining on cozy blankets but on comfortable laps fuels breathless online attention. Eager resellers of flea-market finds advertise hidden mother photographs using terms like “spooky wonderful,” “cutie creepy” and “bizarre.” Articles about them tend to imply a treasure hunt for hiddenness – for adult knees or noses, poised hands, bosoms, hat brims and skirts.

But this common framing reduces their cultural importance to sensationalism: Look at how kooky our ancestors were!

As someone who has studied the history of these photos, I find myself drawing an unlikely connection between these stiff, sepia portraits and modern candid snapshots of mischievous children delighting their adoring mothers. Both are part of the tradition of sentimental image-making that surrounds the iconic figure of mother and child.

Exposure times in 19th-century photography were very long by current standards – 20 to 60 seconds – which helps explain why trusted adults were needed to soothe infant subjects into the stillness necessary to take a portrait. But this technological limitation doesn’t explain why their mothers were half-erased from these photos, which has led scholars to argue that Victorian women were effaced by their culture, and casual viewers to assume that the photographers who produced these visual gaffes were hilariously bad at their craft.

But my research has shown that Victorian photographers were documenting children at a moment of widespread desire to focus cultural attention – and therefore camera lenses – on childhood as a precious time that ought to be protected. And the partial obfuscation of mothers was not inconsistent with images of beloved children, because to cherish is to hold.

These are, in short, images of care.

Evolving photographic forms

Photography was a new technology in the 19th century. Early photographers coated thin metal plates with light-sensitive material, exposed them behind the camera’s lens and developed the plates through precise chemical processes. Each exposure yielded a unique and unreproducible picture directly on the metal.

The fragile daguerreotypes of the early 1840s launched a period of constant experimentation. Photographers eventually perfected sturdier tintypes – also unreproducible images on metal plates – and later revolutionized the medium with glass negatives that enabled multiple prints of the same image. These prints required special paper made light sensitive with a coating of ammonium chloride stabilized in albumen, or egg white. With this process, photography became widely viable as a profession, a hobby and an art. In the 1880s, at the height of its production, the Dresden Albumenizing Company required 60,000 eggs a day to meet worldwide demand for its high-quality photographic paper.

Comparing an 1860s tintype with an 1890s gelatin silver studio print shows the evolution of photographic processes.

The studio portrait is characterized by crisp focus, strong contrast between lights and darks, beautiful mid-tones to contour the baby’s cheek, and artful studio lighting to capture alert infant eyes and the gleam of a mother’s cuff button. The tintype is its opposite in every aspect: Its flattened quality and narrower tonal range are hallmarks of this less technically advanced photographic process.

But in both portraits, the sturdy hands of the loving mother stabilize the child.

Picturing tender connections

Scholars don’t know who was first to use the term hidden mother, although some think it emerged around 2008. A photography exhibit at the Venice Biennale by Linda Fregni Nagler and a lyric photo essay by Laura Larson, both published in 2013 and titled “Hidden Mother,” cemented the moniker, which ironically erases the children who are the focal point of these portraits.

One baby picture in particular – a tintype from the 1850s – tells a story about the development of photographic technology and its role in documenting the fleeting, tender moments of childhood.

The baby’s softness is enhanced by comparison with her mother’s strong jawline. The child’s contemplative gaze suggests deep comfort, snuggled as she is against her mother’s side. The contrast between soft and sharp focus is not just one of emotion but the effect of the little one’s slight movement during the necessarily long exposure time.

The baby’s placidity is partly attributable to the presence of a third figure in this photo. This child appears to be a twin: One of her tiny hands is covered protectively by another, equally small, at the end of another arm clad in an identical dress with braided trim. Grounded in their mother’s lap, these babies exist in a triangulated embrace that memorializes the intimacy of family connections.

Putting the original mat, with its oval cutout, back on the photo makes the baby seem to float, removing the embraces that support her. It also suggests where the moniker for these images, hidden mother, came from. But hands, bodies and the power of touch are central to such images.

Valuing the mother-child bond

Modern viewers often assume that 19th-century customs consigned mothering to the margins. But I argue that this is a projection of ahistorical ideas.

It is a strikingly modern tendency to celebrate women’s ability to have both children and careers, without accounting for how one person will then manage two full-time jobs. Such celebration obscures the labor and time parenting requires in favor of the platitude that if we do what we love, for those we love, it is not work.

Contemporary biases, I suggest, may hide mothers far more than did 19th-century portrait conventions. These images remind thoughtful viewers that babies are held and nursed, soothed and protected, nurtured and guided into independence not by abstract notions of being the right kind of mother, not by oddities, but by embodied human beings.

The historical phenomenon of hidden mothers might be productively renamed “cherished child photographs.” This label more accurately identifies their child subjects and centers the relationship, the cherishing, that is at their heart. It also offers a fruitful avenue for tender contemplation of mothers, children, and the myriad forms of motherwork and bodies who perform them, on Mother’s Day and beyond.

Andrea Kaston Tange, Professor of English, Macalester College

This article is republished from The Conversation under a Creative Commons license. Read the original article.

If you go to the beach and dip a bucket in the sea, you might at first think it contains lifeless water. But examine that water under a microscope and you will see your bucket contains a universe of microscopic life, in the form of beautiful and fascinating plankton.

Plankton are mostly microscopic algae and animals found throughout Earth’s oceans, seas and lakes, although a few species are visible to humans. Unlike fish, plankton can’t swim against the current. Instead, they drift through the water, floating at the will of the waves and tides. Plankton are critical to marine ecosystems and to humans, but often glide under the radar of our interest.

As a plankton ecologist who has worked to raise their profile globally, I hope I can convince you that these creatures deserve your attention.

Phytoplankton, the algae plankton, are single-celled organisms. Many of them have chlorophyll, a green pigment (like land plants) they use for photosynthesis to produce the oxygen we breathe. Throughout time, phytoplankton have produced roughly half of Earth’s oxygen, making our atmosphere inhabitable today.

Like land plants, phytoplankton form the base of the marine food web. While cows graze grass on land, zooplankton, tiny marine animals, eat phytoplankton.

Zooplankton include one of Earth’s most abundant animals, the copepod: a microscopic crustacean ranging in size from 0.5 to 15mm. Large copepods are eaten by larval fish, which scientists also classify as plankton since they are too weak and small to swim against the ocean currents. These larvae grow into fish that are eaten by animals higher up the food web, such as sharks, birds and humans.

Planktonic krill, a shrimp-like crustacean up to 5cm in size, make up most of the diet of the largest vertebrate to ever live on Earth, the blue whale. Blue whales eat by filtering seawater through their comb-like baleen, pushing out water while keeping the plankton in their mouth.

Unlike most sharks, basking sharks and whale sharks don’t have teeth, and eat copepods, krill and other plankton. It’s amazing to think that microscopic animals are the diet of such huge creatures.

Life cycles

Some zooplankton, like copepods and krill, spend their entire lives in the water column between the surface and bottom of the sea, rather than on the seafloor. Other zooplankton only live in the water column during their larval stages, before maturing and settling to the sea floor or, like larval fish, developing the ability to swim against the currents.

In spring, the sea is full of planktonic crab larvae, flicking their tails to swim as they hunt small copepods and other plankton. Crab larvae don’t look like adult crabs: they have huge spines on the tops and bottoms of their heads, and are long and thin rather than round with pincers. As crab larvae grow through their life stages, they look more and more like their adult selves until, finally, they drop to the sea bottom.

Lobsters, mussels, limpets and barnacles also live as plankton in their larvae stages.

Astonishing diversity

Scientists estimate there are around 100,000 plankton species in the sea. Plankton communities vary throughout the Earth’s seas and oceans, particularly with latitude. Warmer waters generally have lower plankton biomass and abundance, and consist of species with smaller body sizes.

Jellyfish, my favourite type of zooplankton, are among the biggest plankton. Despite their large size (up to 120 metres long in the case of the Lion’s Mane jellyfish), jellyfish are still considered plankton because they can’t swim against the currents and tides. Instead, they pulse through the water.

There are other types of plankton which are much smaller. These are the pico- and nano-plankton that are too small to see with a classic microscope. These tiny plankton absorb nutrients from, and help decompose, waste such as faeces, dead organisms and other biological material from other parts of the food web. This microbial loop wasn’t discovered until the 1980s.

There is so much about plankton that we still don’t know, and there are thousands of species yet to be discovered.

Climate change canaries

Plankton are extremely sensitive to changes in their environment, which means they respond quickly to alterations in sea temperature and acidity. As sea temperatures rise, warm water plankton communities are shifting away from the equator, into newly temperate environments, while cold water plankton communities are being squeezed poleward.

In the North-east Atlantic ocean, for example, plankton have shifted 1,000 miles northward since the 1960s. But these aren’t the same individuals moving – this is the whole plankton community shifting, over millions of individual lifespans.

Some plankton groups use calcium carbonate, or chalk, to form their shells. As the oceans acidify, plankton that depend on calcium carbonate struggle to form their shells, which protect them from predators and give their bodies structure.

Coccolithophores, a phytoplankton group covered in calcium carbonate liths (external plates), developed malformations in laboratory experiments that manipulated seawater pH. We are not yet sure of the extent that wild populations of coccolithophores are affected by pH change, but they are certainly important to both marine food webs and the removal of atmospheric carbon.

Plankton may be tiny but phytoplankton blooms, which are dense aggregations of microscopic single-celled phytoplankton, can span hundreds of kilometres across the ocean’s surface, and are visible from space using satellites.

These huge blooms sink to the sea floor when the plankton die, transporting carbon to the deep sea and helping to fight climate change.

While plankton blooms like this are usually natural phenomena, they may also occur due to excess nutrients from farming or sewage. If blooms are too big or too concentrated due to excess nutrients, they can cause hypoxic (no oxygen) dead zones on the seafloor. These kill everything that lives there, including animals that can’t escape this deadzone quickly.

There are few groups that are so biodiverse and important for how our oceans, indeed our entire planet, function. The next time you are on a boat or at the beach and look out at the sea, remember that each drop of water is full of microscopic life that makes our planet what it is.

Abigail McQuatters-Gollop, Associate Professor of Marine Conservation, University of Plymouth

This article is republished from The Conversation under a Creative Commons license. Read the original article.