How glacier algae are challenging the way we think about evolution

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People often underestimate tiny beings. But microscopic algal cells not only evolved to thrive in one of the most extreme habitats on Earth – glaciers – but are also shaping them.

With a team of scientists from the UK and Canada, we traced the evolution of purple algae back hundreds of millions of years and our findings challenge a key idea about how evolution works. Though small, these algae are having a dramatic effect on the glaciers they live on.

Glaciers are among the planet’s fastest changing ecosystems. During the summer melt season as liquid water forms on glaciers, blooms of purple algae darken the surface of the ice, accelerating the rate of melt. This fascinating adaptation to glaciers requires microscopic algae to control their growth and photosynthesis. This must be balanced with tolerance of extreme ice melt, temperature and light exposure.

Our study, published in New Phytologist, reveals how and when their adaptations to live in these extreme environments first evolved. We sequenced and analysed genome data of the glacier algae Ancylonema nordenskiöldii. Our results show that the purple colour of glacier algae, which acts like a sunscreen, was generated by new genes involved in pigment production.

This pigment, purpurogallin, protects algal cells from damage of ultraviolet (UV) and visible light. It is also linked with tolerance of low temperatures and desiccation, characteristic features of glacial environments. Our genetic analysis suggests that the evolution of this purple pigment was probably vital for several adaptations in glacier algae.

We also identified new genes that helped increase the algae’s tolerance to UV and visible light, important adaptations for living in a bright, exposed environment. Interestingly these were linked to increased light perception as well as improved mechanisms of repair to sun damage. This work reveals how algae are adapted to live on glaciers in the present day.

Next, we wanted to understand when this adaptation evolved in Earth’s deep history.

The evolution of glacier algae

Earth has experienced many fluctuations of colder and warmer climates. Across thousands and sometimes millions of years, global climates have changed slowly between glacial (cold) to interglacial (warm) periods.

One of the most dramatic cold periods was the Cryogenian, dating back to 720-635 million years ago, when Earth was almost entirely covered in snow and ice. So widespread were these glaciations, they are sometimes referred to by scientists as “Snowball Earth”.

Scientists think that these conditions would have been similar to the glaciers and ice sheets we see on Earth today. So we wondered could this period be the force driving the evolution of glacier algae?

After analysing genetic data and fossilised algae, we estimated that glacier algae evolved around 520-455 million years ago. This suggests that the evolution of glacier algae was not linked to the Snowball Earth environments of the Cryogenian.

As the origin of glacier algae is later than the Cryogenian, a more recent glacial period must have been the driver of glacial adaptations in algae. Scientists think there has continuously been glacial environments on Earth up to 60 million years ago.

We did, however, identify that the common ancestor of glacier algae and land plants evolved around the Cryogenian.

In February 2024, our previous analysis demonstrated that this ancient algae was multicellular. The group containing glacier algae lost the ability to create complex multicellular forms, possibly in response to the extreme environmental pressures of the Cryogenian.

Rather than becoming more complex, we have demonstrated that these algae became simple and persevered to the present day. This is an example of evolution by reducing complexity. It also contradicts the well-established “march of progress” hypothesis, the idea that organisms evolve into increasingly complex versions of their ancestors.

Our work showed that this loss of multicellularity was accompanied by a huge loss of genetic diversity. These lost genes were mainly linked to multicellular development. This is a signature of the evolution of their simple morphology from a more complex ancestor.

Over the last 700 million years, these algae have survived by being tiny, insulated from cold and protected from the Sun. These adaptations prepared them for life on glaciers in the present day.

So specialised is this adaptation, that only a handful of algae have evolved to live on glaciers. This is in contrast to the hundreds of algal species living on snow. Despite this, glacier algae have dramatic effects across vast ice fields when liquid water forms on glacier surfaces. In 2016, on the Greenland ice sheet, algal growth led to an additional 4,400–6,000 million tonnes of runoff.

Understanding these algae helps us appreciate their role in shaping fragile ecosystems.

Our study gives insight into the evolutionary journey of glacier algae from the deep past to the present. As we face a changing climate, understanding these microscopic organisms is key to predicting the future of Earth’s icy environments.The Conversation

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This blog is written by Dr Alexander Bowles, Postdoctoral research associate, University of Bristol

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

Alexander Bowles
Alexander Bowles

Peru’s ancient water systems can help protect communities from shortages caused by climate change

 

Mount Hount Huascarán, Cordillera Blanca, taken from Hauashao village. Credit: Susan Conlon



Water is essential for human life, but in many parts of the world water supplies are under threat from more extreme, less predictable weather conditions due to climate change. Nowhere is this clearer than in the Peruvian Andes, where rising temperatures and receding glaciers forewarn of imminent water scarcity for the communities that live there.

Peru holds more than 70% of the world’s tropical glaciers. Along the 180 kilometre expanse of the Cordillera Blanca (“white mountains”), more than 250,000 people depend on glaciers for a year-round supply of water. Meltwater from the glaciers supplies rivers, offering a vital supplement to rainwater so that locals can continue irrigating food crops throughout the dry season, from May to October.
But Peruvian glaciers have shrunk by 25% since 1987, and the water supply to rivers during the dry season is gradually decreasing. While national and regional governments and NGOs are responding to the threat of water scarcity with modern engineering solutions, there are growing concerns among the communities affected that such efforts are misplaced.

Modern day misfires

Take, for example, the village of Huashao. Nestled between the highest peaks of the Cordillera Blanca, Huashao is a typical farming village of the region. Glacier meltwater feeds the Yurac Uran Atma canal, which supplies irrigation water to families in Huashao. In 2011, a municipal government project transformed this canal from a rustic irrigation ditch to a modern PVC pipeline, with lock-gates to regulate the flow of water and ensure equal distribution throughout the village.
The village of Huashao. ConDevCenter/Flickr.CC BY-NC-ND
Governments and NGOs commonly promote modern measures to capture and conserve water for irrigation – for example, by lining irrigation canals with concrete, to prevent leakages. While it’s important to conserve water to safeguard food supplies, these kinds of measures have been criticised for their lack of flexibility and sensitivity to local needs.
While the pipeline in Huashao provided security and reduced the amount of time people had to devote to distributing water where it was needed, Conlon’s ongoing ethnographic research in the village found that local women were concerned about its effect on the local puquios (springs) – a valued source of irrigation and drinking water.
Noticing less water in puquios, they blamed the canal lining for stopping water from filtering into the local geology. Local communities see this process as an integral part of water distribution, but authorities often refer to it as “leakage”.
What’s more, the local people responsible for maintaining and operating the new canal found that not everything worked as planned. They were particularly worried when a problem caused water to overflow the canal walls, and blamed the design of the lock–gates.
Here, the government’s preference for modern engineering meant that it missed an opportunity to engage with traditional technologies and local knowledge. This is hardly surprising – ancient know-how has been routinely dismissed as inferior by state authorities and well-meaning (but badly briefed) NGOs. Yet traditional technologies, like the puquios, have been providing flexible ways to manage water in Huashao for hundreds of years.
In Huashao, the local people are coming to realise the limitations of modern engineering. But across the Andes, many other communities are still seduced by the promise of quick fixes offered by concrete, steel and PVC pipelines. Unfortunately, initial, costly investments of aid and expertise are rarely followed up, and since communities often lack the necessary knowledge and funds to maintain these systems, they eventually break down.

Ancient married with modern

Slowly, a push back is starting. There has been renewed interest in what society can learn from traditional irrigation systems. A recent international workshop held in Trujillo, Peru, brought together social scientists, geographers and climate scientists to discuss how to tackle issues around water use and scarcity.
It seems likely that the best solutions will be found by combining old and new knowledge, rather than dismissing one in favour of the other. For instance, parallel to the Cordillera Blanca is the Cordillera Negra (“black mountains”), which faces the Pacific Ocean. Without the benefit of glaciers, the ancient inhabitants of this area learned to harness rain water to see them through the dry season.
These pre-Colombian cultures instigated millennia-long engineering projects, resulting in large dams and reservoirs placed along the slopes of the mountains. These structures controlled water and soil erosion, feeding underground water deposits and providing water for crops and livestock.
An ancient dam in the Cordillera Negra. Kevin Lane.Author provided
Disuse over the last few centuries means that few are still functioning, but those that are, are a tribute to the ancient expertise. By contrast, modern concrete micro-dams have a functional life of 40 to 50 years, often curtailed by seismic activity to between 15 and 25 years.
Fortunately, plans are afoot to revisit these old technologies. Solutions rooted in respect for community and local knowledge, and allied to flexible modern engineering – such as better water retainment technology – are exploring ways in which we can shore-up the effectiveness of these ancient dams.
Throwing money and resources into engineering projects does not always guarantee success when trying to combat the effects of climate change and protect vulnerable communities. But the marriage of ancient and modern technologies offers promising solutions to the threat of water scarcity in Peru, and places like it all across the world.
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This blog is by Cabot Institute member Dr Susan Conlon, Research Associate at the University of Bristol, and Kevin Lane, Senior Researcher in Archeology at Universidad de Buenos Airies. The article is republished from The Conversation under the Creative Commons licence. Read the original article
Dr Susan Conlon

Your Waste of Time: Art-Based Geographical Practices and the Environment

This blog post thinks through the themes of aesthetic interventions, sensing time and engendering response-ability using artistic responses to climate change. Here, these themes are drawn from one piece of art, Your Waste of Time, by Danish-Icelandic artist Olafur Eliasson. This performative showcasing of glacial ice establishes interactions and relations between human bodies and icy materialities- but what is at stake here and what potentialities could be created through artistic practices? These are questions that have arisen through my current dissertation, where I hope to explore artistic responses to environmental degradation through the materialities of ice and plastic.

For the piece Your Waste of Time, Danish-Icelandic artist Olafur Eliasson transported several large blocks of ice from Vatnajökull, the largest and oldest glacier in Iceland, to the Berlin gallery Neugerriemschneider (Eliasson, 2006). This glacier is almost incomprehensibly ancient, with some parts dating from around 1200 AD, but human-driven global warming has begun thawing Vatnajökull, dislodging chunks of ice from the main body of the glacier. This has left behind a scattering of sculpture-like nuggets of ice across the landscape, pieces that untouched, would soon melt away. Eliasson’s project transported these pieces to Germany, to be displayed in an art gallery.

Here the wayfaring blocks of ice were kept in a refrigerated space as immersive sculptures that audience members were encouraged to touch. This was an attempt by Eliasson to bring the visceral reality of human-driven climate change to the attention of the audience through a sensory engagement with ice. In Eliasson’s words, ‘we take away time from the glacier by touching it’ (Eliasson, 2006). Within this molecular moment of sensation between the human and icy touch, the exchange of human warmth is enough to begin to decay the ice. Your Waste of Time then becomes an experiment to curate a sense of environmental care through molecular icy interactions.

Your Waste of Time, Olafur Eliasson, photo by Jens Ziehe
Recently, such environmental artistic interventions have been located temporally with the term ‘anthropocene’[1]. Anthropocene has come into use to refer to human-driven environmental change and degradation. Although the ‘Anthro-pocene’ privileges and homogenises the human (a white, western human) within environmental discourses, the term has become a buzzword for the current era of global pollution and warming. As an imaginary, the Anthropocene cuts through different temporalities; finite human lives, longer lived materialities (such as ice) and geological timescales.

Artistic responses to environmental issues engage with this increasingly unpredictable world, through a sensory engagement with temporality, with other materialities and bodies. It can even be said that ‘attuning ourselves, through poetry, art, and description, to pay attention to other times…these are crucial practices; in fact, they are matters of survival.’ (Davis and Turpin, 2015). Although influential feminist scholar Donna Haraway (2015) proposes other terms such as Capitalocene to denote the specifically capitalist causes of environmental degradation, the Anthropocene also remains an arguably productive term. Art positioned as relating to different temporal imaginaries is thus a speculative, experimental project to think differently, to world differently. Although the term Anthropocene remains contestable, it’s very instability lends itself to artistic conceptual engagements that function through such fragile and indeterminate encounters.

 Image: Your Waste of Time, Olafur Eliasson, photo by Jens Ziehe

 
Positioned in the white, empty space of the art gallery, the fragility of the ice is magnified. This fragility comes to light through the invocation to touch the surface of the icy sculpture. In the words of Eliasson; ‘When we touch these blocks of ice with our hands, we are not just struck by the chill; we are struck by the world itself. We take time from the glacier by touching it’. As Erin Manning (2006), notes in her work on the intersections between art practice and philosophy, sensation opens up the body to thinking and doing differently through its relation to other bodies and things. Touch, in this light, is located neither with the human or the inhuman, but invented through the encounter.

But what happens at a touch? Ice, as sensory aesthetic experience, brings closer together the relations already held between ice and human bodies. Quantum physicist turned feminist philosopher Karen Barad (2012) brings together feminist traditions that unsettle ways of thinking materiality and quantum physics. A sense of touch, for Barad, can be unsettled a molecular exposition of the minute interactions between electrons. This is a murky and confusing world of quantum physics for most social scientists, but Barad productively draws out the indeterminacy at the very building blocks of sensation. Quantum theory holds infinites as integral. This argues for a radical openness of potentialities at the very building-blocks of mattering – all matter is unstable at its foundations. Could it be argued that there is at stake, the unsettling of stable ways of thinking and an opening up of openness already at the heart of mattering?

At the moment of touch between a hand and the blocks of ice, this becomes clear- the warmth of the body causes the ice to change state and start to melt. For Eliasson, ‘We take away time from the glacier by touching it. Suddenly I make the glacier understood to me, its temporality. It is linked to the time the water took to become ice, a glacier. By touching it, I embody my knowledge by establishing physical contact. And suddenly we understand that we do actually have the capacity to understand the abstract with our senses. Touching time is touching abstraction.’ What does it mean to touch time? Touch, as unsettling and in-touch with infinite possibilities could signal a potential for thinking differently. The term anthropocene signals (if problematically) this need to think differently about temporality. The geologic lifespan of the ice is not permanent, but made fragile under a human touch. Temporality, then is not a stable concept either, but one that aesthetic interventions can trouble and disrupt assumptions that time related solely to a stable ticking of the clock.

This touching-time, for Eliasson, has a political undertone. Time is a crucial and sensitive issue in climate change debates. The critical question is, how to engender response-ability and action to do something to halt the tide of environmental degradation and global temperature rise. Haraway (2015) has written about an art project by the Institute of Figuring (2005-ongoing) to crochet coral reefs, involving thousands of people working to cultivate and care for these crochet-corals, gathering each person’s work into an exhibition, curating the corals to establish a reef. Like Your Waste of Time, The Crochet Coral Reef Project has time at its centre. Crocheting, like the establishment of a coral reef, takes time, and has the potential to establish caring relations through the touch of human-material and time. Could art such as this create publics that could do differently concerning climate change?

Image: Crochet Coral Reef Project, Institute of Figuring

 
Care in this context relates to everything that both humans and nonhuman things to continue to repair their world to live as well as possible. These caring relations knit the world together and create complex links between things and humans in the world. Feminist scholar Puig de la Bellacasa (2011) proposes an ethics of care. This care is not a moralism. It is not a case of you should care about environmental degradation! Rather, it is a speculation to see what could happen if we relate to the things and environments around us through more caring relations.

Your Waste of Time, framed through touch, time and care touches upon possible pasts, presents and futures that are framed as undecided. As the ice hovers indeterminately in-between solid and liquid, so does the potential for doing differently. Geologic timescales interact with a momentary present. Could this moment of touch between ice and human engender more caring relations that span other times and other places? Your Waste of Time, then, may not be a waste of time, but rather put us in-touch with time.

Blog by Rosie McLellan

Reposted from ‘Bristol Society and Space‘ Blog of the University of Bristol’s MSc in Human Geography

Bibliography
Barad, K. (2012) ‘On touching – The inhuman that therefore I am’, Differences, 23(3): 206-223
Davis, H. and Turpin, E., eds. (2015), ‘Art in the Anthropocene’, London: Open Humanities Press
De la Bellacasa, M. (2011), ‘Matters of care in technoscience: Assembling neglected things’, Social Studies of Science, 41(1): 85-106
Eliasson, O. (2006), ‘Your Waste of Time’, Berlin: Neugerriemschneider [http://olafureliasson.net/archive/artwork/WEK100564/your-waste-of-time]
Haraway, D. and Kenney, M. (2015), ‘Anthropocene, Capitolocene, Chthulhocene’, in: Davis, H. and Turpin, E., eds. (2015), ‘Art in the Anthropocene’, London: Open Humanities Press
Institute of Figuring, (2005-Ongoing), ‘Crochet Coral Reef Project’, New York: MAD Museum of Modern Arts [http://madmuseum.org/exhibition/crochet-coral-reef-toxic-seas]
Manning, E. (2006), ‘Politics of Touch: Sense, Movement, Sovereignty’, Minneapolis: University of Minnesota Press

See more regarding the Anthropocene at https://www.theguardian.com/environment/2016/aug/29/declare-anthropocene-epoch-experts-urge-geological-congress-human-impact-earth

The controversy of the Greenland ice sheet

I was expecting a dusty road, a saloon door swinging, two geologists standing facing each other in spurrs and cowboy hats with their hands twitching at their sides, both ready to whip out their data and take down their opponent with one well-argued conclusion.

Sadly (for me), things were much more friendly at Professor Pete Nienow‘s seminar in Bristol’s Geographical Sciences department last week. Twelve years ago he visited the University with a controversial hypothesis, causing considerable debate with members of the department. Now he was back, Powerpoint at the ready, to revisit the theory.

Professor Nienow is a glaciologist at the University of Edinburgh. He is currently researching glacial movement and mass in Greenland, but I’ll let him tell you more.


Pete Nienow – GeoScience from Research in a Nutshell on Vimeo.

The Greenland ice sheet covers almost 80% of the country, enclosed by mountains around its edges. The ice sheet is dynamic; glaciers are constantly moving down from the summit towards the sea but replaced each winter by snow. Glaciers are funnelled through the mountains in large “outlet glaciers” that either melt or break into icebergs when they reach the sea.

There is plenty of evidence to suggest that the outlet glaciers are speeding up, rushing down to meet the sea almost twice as fast as they did in the 1970s. Unfortunately that means more melting icebergs floating around, contributing to sea level rise. The winter snowfall is not able to replenish this increased loss of glacial mass, so the Greenland ice sheet is slowly shrinking.

Coverage of the Greenland ice sheet in different future climate change scenarios. A critical tipping
point could be reached, after which it will be impossible to stop the ice from melting and raising sea
levels by seven metres globally.  Source: Alley et al., 2005 (Science)

Controversy

Professor Nienow stirred up a debate in 2002, when he proposed that the Zwally Effect could be hugely important for the Greenland ice sheet. This theory suggests that meltwater could seep down through the glacier to the bedrock, lubricating and speeding up the glacial movement.

The conventional wisdom of the time was that it would be impossible for meltwater to pass through the 2km of solid ice that comprises most of the Greenland ice sheet. The centre of the glacier is around -15 to -20°C, so the just-above-freezing water would never be able to melt its way through.

Meltwater research

Meltwater on glaciers often pools on the surface, creating supraglacial lakes. These lakes can drain slowly over the surface, but Professor Nienow found that they can disappear rapidly too. The water slips down through cracks in the ice to the bedrock, leading to a rapid spike in the amount of meltwater leaving the glacier.

Supraglacial lake.
Source: United States Geological Survey, Wikimedia Commons

Meltwater can reach the base of the glacier so that’s one point to Nienow, but can this actually affect the movement of the glacier?

During the summer, the higher temperatures lead to increased glacial melting, which drains down to the bedrock. This raises the water pressure under the glacier, forcing it to slide more rapidly.  Interestingly, as the season progresses, Nienow found that the meltwater forms more efficient drainage channels beneath the glacier, stabilising the speed of the ice.

Nienow was almost ready to mosey on back to Bristol, show them how subglacial meltwater had clear implications of glacier loss for a warmer world, and declare himself the Last Geologist Standing.

Turning point

Glaciologists had always assumed that the winter glacier velocity was consistently low. However, at the end of a very warm 2010, Nienow and his colleagues discovered a blip of especially low speeds, even slower than the standard winter “constant”.

The large channels underneath the glaciers formed by the extra meltwater of that hot year actually reduced the subglacial water pressure during the winter, slowing the glacier more than on a normal year. Nienow found that this winter variability is critical for overall glacier velocity and displacement. In 2010, the net effect of both summer and winter actually meant that the glacier velocity was reduced in this hot year.

Back to Bristol

Nienow returned to Bristol to give his seminar. Somewhat unlike a cowboy film, Nienow concluded that it was a draw; he’d been right that it was possible for meltwater to seep down to the bedrock and lubricate glacial movement, but his friends at Bristol had been correct in thinking that it wasn’t very important in the grand scheme of things.

A collaborative paper between Professor Nienow, the Bristol team and other glaciologists from around the world found that subglacial meltwater will only have a minor impact on sea level rise, contributing less than 1cm of water globally by 2200.  Surface run off and the production of icebergs will continue to play a bigger role, even in a warming world. The computer models used to predict sea level rise will be able to include these findings to give a more accurate insight into future glacier movement and coverage across Greenland and beyond.

Bristol glaciologist Dr. Sarah Shannon, lead author on the paper, pointed out that whilst overall glacier velocity is unlikely to be affected by subglacial meltwater in warm years, “global warming will still contribute to sea level rise by increasing surface melting which will run directly into the ocean”.

This blog is written by Sarah Jose, Cabot Institute, Biological Sciences, University of Bristol
You can follow Sarah on Twitter @JoseSci

Sarah Jose